WO2004031137A1 - Cyclohexyl sulphone derivatives as gamma-secretase inhibitors - Google Patents

Abstract

Compounds of formula (I) inhibit the processing of APP by gamma-secretase, and hence are useful in treatment of Alzheimer's disease.

Description

CYCLOHEXYL SULPHONE DERIVATIVES AS GAMMA- SECRETASE

INHIBITORS

The present invention relates to a novel class of compounds, their salts, pharmaceutical compositions comprising them, processes for making them and their use in therapy of the human body. In particular, the invention relates to novel cyclohexyl sulphones which inhibit the processing of APP by γ-secretase, and hence are useful in the treatment or prevention of Alzheimer's disease. Alzheimer's disease (AD) is the most prevalent form of dementia.

Although primarily a disease of the elderly, affecting up to 10% of the population over the age of 65, AD also affects significant numbers of younger patients with a genetic predisposition- It is a neurodegenerative disorder, cHnically characterized by progressive loss of memory and cognitive function, and pathologically characterized by the deposition of extracellular proteinaceous plaques in the cortical and associative brain regions of sufferers. These plaques mainly comprise fibrillar aggregates.of β-amyloid peptide (Aβ). The role of secretases, including the putative γ- secretase, in the processing of amyloid precursor protein (APP) to form Aβ is well documented in the literature and is reviewed, for example, -in WO 01/70677.

There are relatively few reports in the literature of compounds with inhibitory activity towards γ-secretase, as measured in cell-based assays. These are reviewed in WO 01/70677. Many of the relevant compounds are peptides or peptide derivatives.

WO 00/50391 discloses a broad class of sulphonamides as - modulators of the production of β-amyloid, but neither discloses nor suggests the compounds of the present invention.

The present invention provides a novel class of cyclohexyl sulphones which are useful in the treatment or prevention of AD by inhibiting the- processing of APP by the putative γ-secretase, thus arresting the production of Aβ.

According to the invention, there is provided a compound of formula I:

I wherein

X represents SCN, SR¹, S(0)R^!, (CR^aR^b)_mS0₂R¹, S0₂N(R²)₂₎ SO2NHCOR¹, S0 NHN(R²)₂, OS0₂N(R²)₂, OS(0)N(R²)₂, OSO2NHCOR¹, COR⁴, NHCORⁱ, NHCO2R¹, NHCON(R²)₂, NHSO2R¹ or NHS0₂N(R²)₂; m is 0 or 1

R^a represents H or Cι-4alkyl;

R^b represents H, Cι-4alkyl, CO2H, Ci ^alkoxycarbonyl orAOi- 4alkylsulphonyl; or R^b may combine with R¹ to form a 5- or 6-membered ring,^' L represents a bond, =CH- or -(CHR^a)_n-; with the proviso that L does not represent a bond when X represents NHCOR¹, NHCO2R¹ or NHSO2R¹; and with the proviso that if L represents =CH", X represents

n is 1, 2 or 3! R¹ represents CF3 or Ci-βalkyl, C2-6alkenyl, C3-9cycloalkyl or

C3-6cycloalkylCι-6alkyl, any of which may bear up to 2 substituents selected from halogen, CN, CF₃, OR³, COR³, CO2R³, OCOR^3a, S0₂R^3a, N(R⁵)₂, and CON(R⁵)₂, or R¹ represents aryl, arylCi-ealkyl, C-heterocyclyl or C-heterocyclylCι-6alkyl»^' - or R¹ may combine with R^b to form a 5- or 6-membered ring; each R² independently represents H, Ci-ealkoxy, or Ci-ealkyl, C2- βalkenyl, C3-9cycloalkyl or Cs-GcycloalkylCi-βalkyl, any of which may bear up to 2 substituents selected from halogen, CN, CF₃, OR³, COR³, CO2R³, OCOR^3a, and CON(R⁵)₂; or aryl, arylCi-ealkyl, C-heterocyclyl or C-heterocyclylCι-6alkyl; or two R groups together with a nitrogen atom to which they are mutually attached complete an N-heterocyclyl group.^"

R³ represents H, Cι-4alkyl, phenyl or heteroaryl;

R^3a represents Ci-4alkyl, phenyl or heteroaryl; R⁴ represents (CR^aR^b)Sθ2R¹, pyridine N-oxide, or phenyl or heteroaryl which bear a substituent selected from C0₂H, methylenedioxy, difluoromethylenedioxy, COR³, C-heterocyclyl, Cι-4alkylsulphonyl and substituted Ci-βalkyl, Ci-βalkoxy, C2-βalkenyl or C2-ealkenyloxy wherein the substituent is selected from halogen, CN, CF₃, OR³, CO2R³, OCOR^3a, N(R⁵) and CON(R⁵)₂;

R⁵ represents H or Cι-4alkyl, or two R⁵ groups together with,a nitrogen atom to which they are mutually attached complete an azetidine, pyrrohdine, piperidine, morpholine, thiomorpholine or thiomorpholine -1,1- dioxide ring; Ar¹ and Ar² independently represent phenyl or heteroaryl, either of which bears 0-3 substituents independently selected from halogen, CN, N0₂, CF₃, CHF₂, OH, OCF₃, CHO, CH=NOH, Cι-₄alkoxy, Cι-4alkoxycarbonyl, C2-βacyl, C2-6alkenyl and Cι-4alkyl which optionally bears a substituent selected from halogen, CN, NO2, CF3, OH and Cι-4alkoxy;

"aryl" at every occurrence thereof refers to phenyl or heteroaryl which optionally bear up to 3 substituents selected from halogen, CN, N0₂, CF₃, OCF3, OR³, COR³, CO2R³, OCOR^3a, N(R⁵)₂, CON(R⁵)₂ and optionally-substituted Ci-βalkyl, Ci-βalkoxy, C2-6alkenyl or C₂-6alkenyloxy wherein the substituent is selected from halogen, CN, CF3, phenyl, OR³, CO2R³, OCOR^3a, N(R⁵)₂ and CON(R⁵)₂; and "C-heterocyclyl" and "N-heterocyclyl" at every occurrence thereof refer respectively to a heterocyclic ring system bonded through carbon or nitrogen, said ring system being non-aromatic and comprising up to 10 atoms, at least one of which is 0, N or S, and optionally bearing up to 3 substituents selected from oxo, halogen, CN, NO2, CF3, OCF3, OR³, COR³, CO2R³, OCOR^3a, OS0₂R^3a, N(R⁵)₂, CON(R⁵)₂ and optionally-substituted phenyl, Ci-ealkyl, Ci-ealkoxy, C₂-ealkenyl or C₂-6alkenyloxy wherein the substituent is selected from halogen, CN, CF₃, OR³, CO2R³, OCOR^3a, N(R⁵)₂ and CON(R⁵)₂; or a pharmaceutically acceptable salt thereof.

Where a variable occurs more than once in formula I, the individual occurrences are independent of each other, unless otherwise indicated. As used herein, the expression "Ci-_Xalkyl" where x is an integer greater than 1 refers to straight-chained and branched alkyl groups wherein the number of constituent carbon atoms is in the range 1 to x. Particular alkyl groups include methyl, ethyl, n-propyl, isopropyl and t-butyl. Derived expressions such as "C2"6alkenyl", "hydroxyCi-βalkyl", "heteroarylCϋ-βalkyl", "C2"6alkynyl" and "Ci-ealkoxy" are to be construed in an analogous manner. The expression "C3"9cycloalkyl" as used herein refers to nonaromatic monocyclic or fused bicyclic hydrocarbon ring systems comprising from 3 to 9 ring atoms. Examples include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclohexenyl and bicyclo[2.2.l]heptyl. Monocyclic systems of 3 to 6 members are preferred. The expression "C3-6 cycloalkylCi-βalkyl" as used herein includes cyclopropylmethyl, cyclobutylmethyl, cyclopentylmethyl and cyclohexylmethyl.

The expression "C2-6acyl" as used herein refers to Ci-salkylcarbonyl groups in which the alkyl portion may be straight chain, branched or cyclic, and may be halogenated. Examples include acetyl, propionyl and trifluoroacetyl. The expression "heterocyclyl" as defined herein includes both monocyclic and fused bicychc systems of up to 10 ring atoms selected from C, N, O and S. Mono- or bicychc systems of up to 7 ring atoms are preferred, and monocyclic systems of 4, 5 or 6 ring atoms are most preferred. Examples of heterocyclic ring systems include azetidinyl, pyrrolidinyl, 3-pyrrolinyl, terahydrofuryl, 1,3-dioxolanyl, tetrahydrothiophenyl, tetrahydropyridinyl, piperidinyl, piperazinyl, morpholinyl, thiomorpholinyl, imidazolidinyl, oxazolidinyl, thiazolidinyl, 2,5-diazabicyclo[2.2.l]heptyl, 2-aza-5-oxabicyclo[2.2.l]heptyl and 1,4- dioxa-8-azaspiro[4.5]decanyl. Unless otherwise indicated, heterocyclyl groups may be bonded through a ring carbon atom or a ring nitrogen atom where present. "C-heterocyclyl" indicates bonding through carbon, while "N-heterocyclyl" indicates bonding through nitrogen.

The expression "heteroaryl" as used herein means a monocyclic system of 5 or 6 ring atoms, or fused bicychc system of up to 10 ring atoms, selected from C, N, O and S, wherein at least one of the constituent rings is aromatic and comprises at least one ring atom which is other than carbon. Monocyclic systems of 5 or 6 members are preferred. Examples- of heteroaryl groups include pyridinyl, pyridazinyl, pyrimidinyl, pyrazinyl, pyrrolyl, furyl, thienyl, pyrazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, imidazolyl, oxadiazolyl, triazolyl and thiadiazolyl groups and benzo-fused analogues thereof. Further examples of heteroaryl groups include tetrazole, 1,2,4-triazine and 1,3,5-triazine. Pyridine rings may be in the N-oxide form. Where a phenyl group or heteroaryl group bears more than one substituent, preferably not more than one of said substituents is other than halogen or alkyl.

The term "halogen" as used herein includes fluorine, chlorine, bromine and iodine, of which fluorine and chlorine are preferred. For use in medicine, the compounds of formula I may advantageously be in the form of pharmaceutically acceptable salts. Other salts may, however, be useful in the preparation of the compounds of formula I or of their pharmaceutically acceptable salts. Suitable pharmaceutically acceptable salts of the compounds of this invention include acid addition salts which may, for example, be formed by mixing a solution of the compound according to the invention with a solution of a pharmaceutically acceptable acid such as hydrochloric acid, sulphuric acid, benzenesulphonic acid, methanesulphonic acid, fumaric acid, maleic acid, succinic acid, acetic acid, benzoic acid, oxalic acid, citric acid, tartaric acid, carbonic acid or phosphoric acid. Alternatively, where the compound of the invention carries an acidic moiety, a pharmaceutically acceptable salt may be formed by neutralisation of said acidic moiety with a suitable base. Examples of pharmaceutically acceptable salts thus formed include alkali metal salts such as sodium or potassium salts; ammonium salts; alkaline earth metal salts such as calcium or magnesium salts; and salts formed with suitable organic bases, such as amine salts (including pyridinium salts) and quaternary ammonium salts.

Where the compounds according to the invention have at least one asymmetric centre, they may accordingly exist as enantiomers. Where the compounds according to the invention possess two or more asymmetric '* centres, they may additionally exist as diastereoisomers. It is to be understood that all such isomers and mixtures thereof in any proportion are encompassed within the scope of the present invention.

In the compounds of formula I, X represents SCN, SR¹, S^R¹, (CR^aR^b)_mS0₂R¹, S0₂N(R²)₂, S02NHCOR¹, S0₂NHN(R²)₂, OS0₂N(R²)₂, OS(0)N(R²)₂, OSO2NHCOR¹, COR⁴, NHCORⁱ, NHC02R¹, NHCON(R²)₂, NHSO2R¹ or NHS0₂N(R²)₂. In a preferred embodiment, X is selected from SR¹, (CR^aR^b)_mSO₂R¹, SO₂N(R²)₂, OSO₂N(R²)₂₎ COR⁴, NHCOR¹, NHCO2R¹, NHCON(R²)₂, NHSOsR¹ and NHS0₂N(R²)₂.

When X represents (CR^^mSO^¹, m is 0 or 1. In one embodiment, m is 0. In an alternative embodiment, m is 1. When m is 1, R^a represents H or Cι-4alkyl such as methyl, ethyl or propyl. When m is 1, R^b represents H, Cι-4alkyl (such as methyl, ethyl or propyl), CO2H, Cι-4alkoxycarbonyl (such as Cθ2Me or C0₂Et) or Ci- ₄alkylsulphonyl (such as methanesulphonyl); or R^b may combine with R¹ to form a 5- or 6-membered ring, in particular a tetrahydrothiophene-1,1- dioxide ring or a tetrahydrothiopyr an -1,1 -dioxide ring.

When m is 1, preferred identities for the moiety - CR^aR^b- include :

^■ Eat. ^E 1 ^t

— CH— — CH— I _c

C and 1

CO₂H CO₂Et I^_{O H C}o_2Et •

L represents a bond, =CH- or -(CHR^a)_n->^' but when L represents a bond, X cannot represent NHCOR¹, NHCO2R¹ or NHSC^R¹; and when L represents =CH , X must represent SO2R¹ or COR⁴.

When L represents a bond or -(CHR^a)_n-, the moiety — LrX is preferably in the cis stereoconfiguration relative to the Ar¹S02 moiety.

When L represents — (CHR^a)_n", n is 1, 2 or 3 (preferably 1 or 2), and each R^a is independently H or Cι-4alkyl such as methyl or ethyl (especially methyl), but L preferably comprises not more than one R group that is other than H.

Particularly preferred examples of L include a bond, -CH2- and "CH₂CH₂-. R¹ is preferably CF3, aryl or arylalkyl, or an alkyl, cycloalkyl or cycloalkylalkyl group, optionally substituted as described previously. Preferred substituents include halogen (especially fluorine or chlorine), CF₃, CN, OR³ (especiaUy OH, OMe and OEt), COR³ (especially acetyl), CO2R³ (especially C0₂H, C0₂Me and C0₂Et) and CON(R⁵)₂ (especially CONH₂).

Examples of alkyl groups represented by R¹ include methyl, ethyl, n-propyl, isopropyl, t-butyl, isobutyl, 2,2,2-trifluoroethyl, cyanomethyl, 2- hydroxyethyl, 2-methoxyethyl, 2-hydroxy-2-methylpropyl, carboxymethyl, ethoxycarbonylmethyl, 1-carboxyethyl, 1-ethoxycarbonylethyl, carbamoylmethyl and MeCOCH₂-.

Examples of cycloalkyl and cycloalkylalkyl groups represented by R¹ include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclopropylmethyl and cyclopentylmethyl.

When R¹ represents aryl or arylalkyl, the aryl group may be phenyl or heteroaryl, optionally substituted as defined previously. Preferred substituents include halogen (especially chlorine or fluorine), CF3, OCF3, alkyl (especially methyl), OH and alkoxy (especially methoxy). Preferred heteroaryl groups include pyridine, pyrimidine, furan, thiophene, thiazole, imidazole, triazole, thiadiazole and tetrazole.

Examples of aryl groups represented by R¹ include phenyl, 2- fluorophenyl, 4-fluorophenyl, 2,4-difluorophenyl, 2-chlorophenyl, 2", 3- and, 4-hydroxyphenylj 2-trifluoromethoxyphenyl, 2-methoxyphenyl, 2-pyridyl (and the corresponding N-oxide), 4-pyridyl, 2 -pyrimidinyl, 2-furyl, 2- thienyl, 2-thiazolyl, 2-imidazolyl, 2-methylfuran-3-yl, 4-methylthiazol-3-yl, . 5-methyl-l,3,4-thiadiazol-2-yl, l-methylimidazol-2-yl, l-methyl-1,2,3,4- tetrazol-5-yl, l,2,4-triazol-3-yl, l-methyl-l,2,4-triazol-3-yl, 2-methyM,2,4- triazol-3-yl and 4-methyM,2,4-triazol-3-yl. Arylalkyl groups represented by R¹ are typically optionally substituted benzyl, phenethyl, heteroarylmethyl or heteroarylethyl groups. Examples include benzyl, 2-furylmethyl, 2-thienylmethyl and 1- (2-thienyl)ethyl.

When X represents SO2NHCOR¹ or OSO2NHCOR¹, R¹ is very aptly CF3, Ci-βali-yl or C3-ecycloalkyl, for example methyl.

When X represents S(O)R¹, R¹ very aptly represents aryl, for example 2-pyridyl or l-methyl-l,2,3-,4"tetrazol-5-yl.

When X represents NHCO2R¹, R¹ very aptly represents Ci-βalkyl (for example methyl) or arylalkyl (for example benzyl). When X represents NHCOR¹, R¹ very aptly represents Ci-ealkyl (for example methyl) or substituted Ci-ealkyl (for example 2,2,2-trifluoroethyl or 1 -hydroxy- 2, 2, 2-trifluoroethyl) .

For any N(R²)2 fragment, preferably either at least one of the R² groups represents H or Ci-ealkyl such as methyl, or the two R² groups complete an N-heterocyclyl group. When one R² group represents Ci- ealkoxy (such as methoxy), the other preferably represents Cι-6alkyl (such as methyl).

When N(R²)2 does not represent N-heterocyclyl, preferably one R² is H or methyl and the other is H, methoxy, aryl (such as phenyl) or optionally substituted alkyl or cycloalkyl. Preferred substituents include CF₃, OR³ (such as OH and OMe), C0₂R³ (such as t-butoxycarbonyl) and OCOR^3a (such as acetoxy). Within this embodiment, preferred identities for N(R²)₂ include NH₂, NHMo. NHEt, NHⁱPr, NHΦu, NMe₂₎ N(Me)OMe, NHPh, NH-cyclobutyl, NHCH CFs, NHCH₂C0₂ ^tBu, NHCH₂CH₂OCOMe

When N(R²)2 represents N-heterocyclyl, the heterocyclic ring is typically an optionally substituted azetidine, pyrrohdine, 3 -pyrroline, piperidine, morphohne, thiomorpholine or 2-aza-5- oxabicyclo[2.2.l]heptane ring. Azetidine and pyrrohdine are preferred, and azetidine is particularly preferred. Preferred substituents include oxo, halogen (especially fluorine), CF3, OR³ (especially OH), OCOR^3a (especially acetoxy and trimethylacetoxy), OS0₂R^3a (especially methanesulphonyloxy), CO2R³ (especially C0₂H and Cθ2Me), N(R⁵)2 (especially dimethylamino) and alkyl (especially methyl). Examples of preferred N-heterocyclyl groups include azetidin-1-yl, pyrrolidin-1-yl, 3- pyrrolin-1-yl, piperidin-1-yl, morpholin-4-yl, thiomorphohn-4-yl, 2-aza-5- oxabicyclo[2.2.l]hept-2-yl, 3-oxo-azetidin-l-yl, 3 -hydroxy azetidin-1-yl, 3- acetoxyazetidin-1-yl, 3- (dimethylamino) azetid vl-yl, 3- methanesulphonyloxyazetidin-1-yl, 3,3-difluoroazetidin-l-yl, 3"hydroxy-3- methylazetidin-1-yl, 2-carboxypyrroUdin-l-yl, 2- methoxycarbonylpyrrolidin-1-yl, 3-fluoropyrrolidin-l-yl, 3,3- difluoropyrrolidin-1-yl, 2-(trifluoromethyl)pyrrolidin-l-yl, 3-oxo-pyrrolidin- 1-yl, 3-hydroxypyrrolidin-l-yl, 3-hydroxy-3-methylpyrrohdin-l-yl, 3- (trime thy lace toxy)pyrrolidin- 1-yl, 4-(trifluoromethyl)piperidin- 1-yl and 4,4-difluoropiperidin-l-yl.

When X represents S0₂NHN(R²)₂, OS(0)N(R²)₂ or NHCON(R²)₂₎ very aptly both R² groups represent methyl, or one R² represents H and the other represents Ci-ealkyl, such as methyl or ethyl.

In the embodiments in which X represents COR⁴, R⁴ is selected from (CR^aR^b)S02R¹, pyridine N-oxide, or phenyl or heteroaryl which is substituted as defined previously.

When R⁴ represents (CR^aR^b)Sθ2R¹, R^a and R^b preferably independently represent H or Cι-₄alkyl, or R^b together with R¹ completes a 5- or 6-membered ring. Suitable rings include tetrahydrothiophene-1,1,- dioxide and tetrahydrothiopyran-l,l-dioxide. Tetrahydrothiophene-1,1,- dioxide is preferred. In this context, R¹ is very aptly optionally-substituted Ci-βalkyl, especially methyl, or else completes a ring with R^b. Examples of preferred groups represented by R⁴ in this embodiment include CH₂S0₂Me, CH(Me)S0₂Me, C(Me)₂S0₂Me and 1,1-dioxo- tetrahydrothiophen-2-yl.

When R⁴ represents pyridine N-oxide, the pyridine ring may be bonded through the 2-, 3- or 4-position, but the 2-position is preferred.

R⁴ may alternatively represent phenyl or heteroaryl, either of which must bear a substituent selected from CO2H, methylenedioxy, difluoromethylenedioxy, COR³, C-heterocyclyl, Cι-4alkylsulphonyl and substituted Ci-βalkyl, Ci-βalkoxy, C2-6alkenyl or C2-βalkenyloxy wherein the substituent is selected from halogen, CN, CF₃, OR³, CO2R³, OCOR^3a, N(R⁵)₂ and CON(R⁵)₂. In this context, preferred heteroaryl groups are 5- membered, such as furan, pyrrole, and thiophene, furan and pyrrole being particularly preferred and furan most preferred. Examples of preferred substituents include C0₂H, difluoromethylenedioxy, formyl, 1,3-dioxolan- 2-yl, methanesulphonyl, hydroxymethyl, allyl, allyloxy, -(CH2)_x-Cθ2R³, -0(CH₂)y-Cθ2R³, -CH=CH-CO₂R³, -(CH₂)_X-N(R⁵)₂ and -0(CH₂)_y-N(R⁵)₂, where x is 1, 2 or 3 and y is 2 or 3. In this context R³ is very aptly H, methyl or ethyl, and N(R⁵)2 is very aptly morpholin-4-yl or 1,1-dioxo- thiomorpholin-4-yl.

Ar¹ and Ar² independently represent optionally substituted phenyl or heteroaryl. Ar¹ is preferably selected from optionally substituted phenyl and optionally substituted 6-membered heteroaryl. Preferred 6- membered heteroaryl embodiments of Ar¹ include optionally substituted pyridyl, in particular optionally substituted 3 -pyridyl. Ar¹ is preferably selected from 6-(trifluoromethyl)-3-pyridyl and phenyl which is optionally substituted in the 4-position with halogen, CN, vinyl, allyl, acetyl, methyl or mono-, di- or trifluoromethyl. In one preferred embodiment of the invention Ar¹ represents 4-chlorophenyl. In another preferred embodiment Ar¹ represents 4-trifluoromethylphenyl. In a further preferred embodiment A¹ represents 6 -(trifluoromethyl) -3 -pyridyl. Ar² preferably represents optionally substituted phenyl, in particular phenyl bearing 2 or 3 substituents selected from halogen, CN, CF3 and optionally-substituted alkyl. Ar² is typically selected from phenyl groups bearing halogen substituents (preferably fluorine) in the 2- and 5- positions or in the 2-, 3- and 6-positions, or from phenyl groups bearing a fluorine substituent in the 2-position and halogen, CN, methyl or hydroxymethyl in the 5 -position. In a preferred embodiment of the invention, Ar² represents 2,5-difluorophenyl. In a particular embodiment, Ar¹ is 4-chlorophenyl or 4- trifluoromethylphenyl or 6 -(trifluoromethyl) -3 -pyridyl and Ar² is 2,5- difluorophenyl.

A subclass of the compounds of the invention comprises the compounds of formula IP

II wherein n, X, Ar¹ and Ar² have the same definitions and preferred identities as before; and pharmaceuticaUy acceptable salts thereof. Preferably n is 1 or 2.

In a subset of the compounds of formula II, X is selected from NHCOR¹, NHC02R¹ and NHSO^¹ where R¹ has the same definition and preferred identities as before.

A second sub-class of the compounds of the invention comprises the compounds of formula IIP

III wherein p is 0, 1, 2 or 3;

Y is SCN, SR¹, S(O)R¹, (CR^aR )_mS0₂R¹, S0₂N(R )₂, SO2NHCOR¹, S0₂NHN(R²)₂, OS0₂N(R²)₂₎ OS(0)N(R²)₂, OSO2NHCOR¹, COR⁴, NHCON(R²)₂ or NHS0₂N(R²)₂; and m, R^a, R^b, R¹, R², R⁴, Ar¹ and Ar² have the same definitions and preferred identities as before! and pharmaceutically acceptable salts thereof.

Preferably p is 0, 1 or 2. In a subset of the compounds of formula III, Y is selected from SCN,

SR¹, S(0)Rⁱ, (CR^aR )_mS0₂R¹, S0₂N(R²)₂, SO2NHCOR¹ and S0₂NHN(R²)₂; preferably from SCN, SR¹, (CR^aR^b)_mSO₂R¹ and S0₂N(R²)₂; and most preferably from (CR^aR )_mSO R¹ and SO₂N(R²)₂. Within this subset, p is preferably 1 or 2. In one preferred embodiment Y is (CR^aR^b)_mS0₂R¹. In another preferred embodiment Y is Sθ2N(R²)₂, in which case p is very aptly 1 and N(R²)₂ is very aptly N-heterocyclyl.

In a second subset of the compounds of formula III, Y is selected from OSO₂N(R²)₂, OS(O)N(R²)₂, OSO2NHCOR¹, NHCON(R²)₂, NHS0₂N(R²)₂ and COR⁴. Within this subset, p is preferably 0 or 1. In one preferred embodiment p is 0 and Y is OS0₂N(R²)2. In another preferred embodiment, p is 1 and Y is NHCON(R²)2. In a further preferred embodiment, p is 1 and Y is COR⁴. In a further preferred embodiment, p is 0 and Y is NHS02N(R²)2. In a further preferred embodiment, p is 1 and Y is NHS0₂N(R²)₂.

A third sub-class of the compounds of the invention comprises the compounds of formula IV:

IV wherein Z represents SO2R¹ or COR⁴; and R¹, R⁴, Ar¹ and Ar² have the same definitions and preferred identities as before; and pharmaceutically acceptable salts thereof. In a preferred embodiment, Z is SO2R¹.

Examples of individual compounds in accordance with the invention are provided in the Examples section appended hereto.

The compounds of formula I have an activity as modulators of the processing of APP by γ-secretase.

The invention also provides pharmaceutical compositions comprising one or more compounds of formula I or the pharmaceutically acceptable salts thereof and a pharmaceutically acceptable carrier.

Preferably these compositions are in unit dosage forms such as tablets, pills, capsules, powders, granules, sterile parenteral solutions or suspensions, metered aerosol or liquid sprays, drops, ampoules, transdermal patches, auto-injector devices or suppositories; for oral, parenteral, intranasal, sublingual or rectal administration, or for administration by inhalation or insufflation. For preparing solid compositions such as tablets, the principal active ingredient is mixed with a pharmaceutical carrier, e.g. conventional tableting ingredients such as corn starch, lactose, sucrose, sorbitol, talc, stearic acid, magnesium stearate, dicalcium phosphate or gums or surfactants such as sorbitan monooleate, polyethylene glycol, and other pharmaceutical diluents, e.g. water, to form a solid preformulation composition containing a homogeneous mixture of a compound of the present invention, or a pharmaceutically acceptable salt thereof. When referring to these preformulation compositions as homogeneous, it is meant that the active ingredient is dispersed evenly throughout the composition so that the composition may be readily subdivided into equally effective unit dosage forms such as tablets, pills and capsules. This sohd preformulation composition is then subdivided into unit dosage forms of the type described above containing from 0.1 to about 500 mg of the active ingredient of the present invention. Typical unit dosage forms contain from 1 to 250 mg, for example 1, 2, 5, 10, 25, 50, 100, 200 or 250 mg, of the active ingredient. , The tablets or pills of the novel composition can be coated or otherwise - compounded to provide a dosage form affording the advantage of prolonged action. For example, the tablet or pill can comprise an inner dosage and an outer dosage component, the latter being in the form of an envelope over the former. The two components can be separated by an enteric layer which serves to resist disintegration in the stomach and permits the inner component to pass intact into the duodenum or to be delayed in release. A variety of materials can be used for such enteric layers or coatings, such materials including a number of polymeric acids and mixtures of polymeric acids with such materials as shellac, cetyl alcohol and cellulose acetate. The liquid forms in which the novel compositions of the present invention may be incorporated for administration oraUy or by injection include aqueous solutions, suitably flavoured syrups, aqueous or oil suspensions, and flavoured emulsions with edible oils such as cottonseed oil, sesame oil or coconut oil, as well as elixirs and similar pharmaceutical vehicles. Suitable dispersing or suspending agents for aqueous suspensions include synthetic and natural gums such as tragacanth, acacia, alginate, dextran, sodium carboxymethylcellulose, methylcellulose, poly(vinylpyrrolidone) or gelatin. The present invention also provides a compound of formula I or a pharmaceutically acceptable salt thereof for use in a method of treatment of the human body. Preferably the treatment is for a condition associated with the deposition of β-amyloid. Preferably the condition is a neurological disease having associated β-amyloid deposition such as Alzheimer's disease.

The present invention further provides the use of a compound of formula I or a pharmaceutically acceptable salt thereof in the manufacture of a medicament for treating or preventing Alzheimer's disease.

The present invention further provides a method of treatment of a subject suffering from or prone to a condition associated with the deposition of β-amyloid which comprises administering to that subject an effective amount of a compound according to formula I or a pharmaceutically acceptable salt thereof. Preferably the condition is a neurological disease having associated β-amyloid deposition such as Alzheimer's disease.

For treating or preventing Alzheimer's Disease, a suitable dosage level is about 0.01 to 250 mg/Kg per day, preferably about 0.10 to 100 mg/Kg per day, especially about 1.0 to 50 mg/Kg, and for example about 10 to 30 mg/Kg of body weight per day. Thus, a dose of about 500mg per person per day may be considered. The compounds may be administered on a regimen of 1 to 4 times per day. In some cases, however, dosage outside these limits may be used.

Compounds of formula I in which L is -(CH2V and X represents SCN, SR¹ or (CR^aR^b)_mS02R¹ may be prepared by reaction of, respectively, MSCN, MSR¹ or M(CR^aR )_mS0₂R¹ with a compound of formula (l):

(1) where M is a metal cation (preferably an alkah metal cation, such as Li or Na), G is a leaving group, and R¹, R^a, R^b, Ar¹, Ar², m and p have the same meanings as before. Suitable identities for G include halide (especially bromide or iodide) and alkyl- or arylsulphonate. Iodide and mesylate are particularly suitable. The metaUated derivatives MSR¹ and M(CR^aR^b)mS0₂R¹ may be generated by reaction of the corresponding hydrides with NaOH, LiOH, NaH, BuLi, LiN(ⁱPr) or similar, and are typically reacted in situ with the compounds (l). Compounds of formula I in which X represents S(0)R^x may be prepared from the corresponding compounds in which X represents SR¹ by oxidation with one equivalent of m -chloroperoxybenzoic acid. The oxidation takes place at ambient temperature in a dichloromethane -water mixture. Oxidation of the same compounds with two equivalents of m- chloroperoxybenzoic acid, or with sodium periodate in the presence of Ru0₂ catalyst, provides an alternative route to compounds in which X represents (CR^aR^b)_mSθ2R¹ and m is 0.

Compounds of formula I in which L is -(CH2V and X represents , S0₂N(R²)₂ or S0₂NHN(R²)₂ may be prepared by reaction of (R²)₂NH or (R²)₂NNH₂ respectively with a sulphonyl chloride of formula (2):

(2) where R², Ar¹, Ar² and p have the same meanings as before. The reaction is typically carried out in dichloromethane at ambient temperature, either using excess of the amine or using an additional base such as potassium carbonate, pyridine or triethylamine.

Compounds of formula I in which X represents S02NHCOR¹ may be prepared from the corresponding compounds in which X represents S0₂NH₂ by coupling with R¹C0₂H. Any of the standard peptide couphng procedures may be used, for example the use of dimethylaminopyridine and l-(3-dimethylaminopropyl)-3-ethylcarbodiimide.

Compounds of formula I in which L is -(CH₂)p- and X represents OS0₂N(R²)₂ may be prepared by reaction of a sulphamoyl chloride (R²)₂NS0₂C1 with an alcohol of formula (3):

(3) where R², Ar¹, Ar² and p have the same meanings as before. The reaction is typically carried out in dichloromethane at ambient temperature in the presence of a base such as pyridine or triethylamine. The sulphamoyl chlorides (R²)₂NS02C1 are available by reaction of (R²)2NH with sulphuryl chloride in acetonitrile at ambient temperature. Compounds of formula I in which X represents OSO2NHCOR¹ may be prepared from the corresponding compounds in which X represents OSO₂NH₂ by couphng with R¹CO₂H. Any of the standard peptide couphng procedures may be used, for example the use of dimethylaminopyridine and l-(3-dimethylaminopropyl) -3-ethylcarbodhmide. Compounds of formula I in which L is -(CH₂)_P- and X represents OS(0)N(R²)₂ may be prepared by treating an alcohol of formula (3) first with thionyl chloride, and then with (R²)₂NH. The reaction with thionyl chloride is typically carried out at -78°C, and the resulting intermediate reacted in situ with the amine at the same temperature, then allowed to warm to ambient temperature.

Compounds of formula I in which L is -(CH₂)_p- and X represents NHCOR¹, NHCO2R¹, NHSO2R¹ or NHS0₂N(R²)₂ may be prepared by reacting an amine of formula (4) with, respectively, RⁱCOCl, ROCOCl, R¹S0₂C1 and (R²)₂NS0₂C1:

(4) where R¹, Ar¹, Ar² and p have the same meanings as before. The reaction is typically carried out in dichloromethane at ambient or reduced temperature, in the presence of a base such as pyridine or triethylamine. Alternatively, the compounds in which X represents NHCOR¹ may be prepared by couphng of amines (4) with R¹Cθ2H. Any of the standard peptide couphng procedures may be used, for example the use of 1- hydroxybenzotriazole or dimethylaminopyridine and l-(3- dimethylaminopropyl) - 3 -ethylcarbodiimide . An alternative route to the compounds of formula I in which L is —

(CH2 and X represents NHS0₂N(R²)₂ involves reacting an amine of formula (4) with catechol sulphate and reacting the resulting sulphamate with (R²)₂NH. The first step is typically carried out in THF at 0°C, and the second step at 80°C in dioxan. Compounds of formula I in which L is — (CH₂)_P- and X represents

NHCON(R²)₂ may be prepared by treating an carboxyhc acid of formula (5) first with diphenylphosphoryl azide, and then with (R²)2NH:

(5) where R², Ar¹, Ar² and p have the same meanings as before. The first step is typically carried out in toluene at 110°C in the presence of triethylamine, and the second step at ambient temperature in the same solvent.

Compounds of formula I in which X represents COR⁴, and R⁴ represents substituted phenyl or heteroaryl, may be prepared by reaction of a compound of formula (6a) with R⁴-M^χ:

(6) where M¹ represents Li or MgBr and Ar¹, Ar² and L have the same meanings as before. The reaction is typically carried out in THF or diethyl ether at reduced temperature. When M¹ is MgBr, R⁴ preferably represents substituted phenyl.

Compounds of formula I in which X represents COR⁴, and R⁴ represents (CR^aR^b)Sθ2R¹, may be prepared by reaction of a compound of formula (6b) with R⁴-Li. The reaction is typically carried out in THF or diethyl ether at reduced temperature.

Compounds of formula I in which L represents =CH- and X represents SO2R¹ may be prepared by reaction of a cyclohexanone (7):

(7) with CH3-SO2R¹, followed by dehydration of the resulting tertiary alcohol; where R¹, Ar¹ and Ar² have the same meanings as before. The first step is typically carried out in THF at -78°C in the presence of strong base such as lithium diisopropylamide. The dehydration may be effected by converting the alcohol to the corresponding mesylate and treating the latter with l,8-diazabicyclo[5.4.θ]undec-7-ene in THF at ambient temperature.

The compounds of formula (l) in which G is iodide may be obtained by reaction of the corresponding compounds of formula (5) with iodosobenzene diacetate and iodine under irradiation. The compounds of formula (l) in which G is alkyl- or arylsulphonate are available from the reaction of the corresponding compounds of formula (3) with the appropriate sulphonyl chloride.

The sulphonyl chlorides of formula (2) may be obtained by reaction of the compounds of formula (l) with potassium thioacetate, hydrolysis of the resulting thioester to give the corresponding thiol, then treatment of the thiol with potassium nitrate and sulphuryl chloride.

The alcohols of formula (3) in which p is 1, 2 or 3 are available by reduction of the acids of formula (5), the value of p increasing by 1 in the process. The alcohols of formula (3) in which p is 0 are available from the reduction of the cyclohexanones of formula (7). Reduction with L- Selectride™ provides the cis isomer selectively. Reduction with sodium borohydride provides a mixture of cis and trans isomers which may be separated by chromatography. The amines of formula (4) are available from the carboxylic acids (5) by sequential reaction with oxalyl chloride, sodium azide and benzyl alcohol, followed by hydrolysis of the resulting carbamate. Alternatively, they may be obtained from the mesylates of the alcohols (3) by displacement with azide ion, followed by reduction. The carboxyhc acids of formula (5) in which p is 0 are available from the alcohols (3) in which p is 0 by formation of the mesylate ester, followed by nucleophilic displacement with cyanide ion and hydrolysis of the resulting nitrile. The corresponding acids in which p is 1 are formed by condensation of cyclohexanones (7) with ethyl

(diethoxyphosphinyDacetate, followed by reduction of the resulting alkenyl ester (i.e. (6b) where L is =CH>) and hydrolysis of the ester group. The corresponding acids in which p is 2 or 3 are obtainable by standard methods of homologation. For example, reduction of an acid (5) in which p is 1 provides an alcohol (3) in which p is 2, and mesylation, displacement with cyanide, and hydrolysis provides the corresponding acid in which p is 2. Repeating this process provides the acid (5) in which p is 3.

The N-methoxyamides (6a) are obtained-from the corresponding carboxyhc acids by treatment first with oxalyl chloride and then with N,0- dimethylhy droxyl amine .

Detailed procedures for the synthesis of compounds of formulae (l) (6), and cyclohexanones (7), are provided in WO 02/081435 and US 2003/0114496 Al.

It will be apparent to those skilled in the art that individual compounds of formula I prepared by the above routes may be converted into other compounds in accordance with formula I by means of well known synthetic techniques such as alkylation, esterification, amide coupling, hydrolysis, oxidation and reduction. Such techniques may likewise be carried out on precursors of the compounds of formula I. For example, a compound of formula I in which X is SCN may be treated with trimethyl(trifluoromethyl)silane and tetrabutylammonium fluoride to provide the corresponding compound in which X is SCF3, which in turn may be oxidised to the corresponding compound wherein X is SO2CF3. Similarly, a compound of formula I wherein X is (CR^aR^b)Sθ2R¹ or CO(CR^aR^b)S0₂R¹ and one or both of R^a and R is H may be alkylated so as to provide the corresponding compound in which one or both of R^a and R^b is alkyl. Alternatively, if in the aforesaid compound R^b is CO2H, decarboxylation via refluxing with sodium chloride in DMSO provides the corresponding compound in which R^b is H.

Also, substituents on the aromatic groups Ar¹ or Ar² may be added or interconverted by means of standard synthetic processes carried out on the compounds of formula I or their precursors. For example, in esters

(6b) a chlorine or bromine atom on Ar¹ or Ar² may be replaced by vinyl by treatment with vinyltributyltin in the presence of tri-t-butylphosphine, cesium fluoride and tris(dibenzylideneacetone)dipalladium(θ). Ozonolysis of the vinyl group provides the corresponding formyl derivative, which may be transformed in a variety of ways, including oxidation to the corresponding acid, reduction to the corresponding benzyl alcohol, and conversion to the corresponding nitrile by treatment with hydroxyla,mine then triphenylphosphine and carbon tetrachloride.

Compounds of formula I in which L comprises a pendant alkyl group are obtainable by alkylation of the corresponding compounds wher.ein L is

— (CH₂)rT, or by alkylation of a precursor such as an ester (6b) wherein L is

-(CH₂)_n-.

Pyridine groups may be oxidised to the corresponding N-oxides by treatment with urea hydrogen peroxide and trifluoroacetic anhydride in dichloromethane at 0°C.

Where they are not themselves commercially available, the starting materials and reagents employed in the above -described synthetic schemes may be obtained by the apphcation of standard techniques of organic synthesis to commercially available materials. It will be appreciated that many of the above -described synthetic schemes may give rise to mixtures of stereoisomers. Such mixtures may be separated by conventional means such as fractional crystallisation and - preparative chromatography.

Certain compounds according to the invention may exist as optical isomers due to the presence of one or more chiral centres or because of the overall asymmetry of the molecule. Such compounds may be prepared in racemic form, or individual enantiomers may be prepared either by enantiospecific synthesis or by resolution. The novel compounds may, for example, be resolved into their component enantiomers by standard techniques such as preparative HPLC, or the formation of diastereomeric pairs by salt formation with an optically active acid, such as

(-)-di-p-toluoyl-d-tartaric acid and/or (+)-di-p-toluoyH-tartaric acid, followed by fractional crystallisation and regeneration of the free base. The novel compounds may also be resolved by formation of diastereomeric esters or amides, followed by chromato graphic separation and removal of the chiral auxiliary.

During any of the above synthetic sequences it may be necessary and/or desirable to protect sensitive or reactive groups on any of the molecules concerned. This may be achieved by means of conventional protecting groups, such as those described in Protective Groups in Organic Chemistry, ed. J.F.W. McOmie, Plenum Press, 1973; and T.W. Greene & P.G.M. Wuts, Protective Groups in Organic Synthesis, John Wiley & Sons, 3^rd ed., 1999. The protecting groups may be removed at a convenient- subsequent stage using methods known from the art.

An assay which can be used to determine the level of activity of compounds of the present invention is described in WO01/70677. A preferred assay to determine such activity is as follows^ l) SH-SY5Y cells stably overexpressing the βAPP C-terminal fragment SPA4CT, are cultured at 50-70% confluency. lOmM sodium butyrate is added 4 hours prior to plating. 2) Cells are plated in 96-weU plates at 35,000 cells/well/lOOμL in Dulbecco's minimal essential medium (DMEM) (phenol red -free) + 10% foetal bovine serum (FBS), 50mM HEPES buffer (pH7.3), 1% glutamine. 3) Make dilutions of the compound plate. Dilute stock solution 18.2x to 5.5% DMSO and llx final compound concentration. Mix compounds vigorously and store at 4°C until use. 4) Add lOμL compound/well, gently mix and leave for 18h at 37°C, 5% C0₂.

5) Prepare reagents necessary to determine amyloid peptide levels, for example by Homogeneous Time Resolved Fluorescence (HTRF) assay. 6) Plate 160μL ahquots of HTRF reagent mixture to each well of a black 96-well HTRF plate.

7) Transfer 40μL conditioned supernatant from cell plate to HTRF plate. Mix and store at 4°C for 18 hours.

8) To determine if compounds are cytotoxic following compound administration, cell viabihty is assessed by the use of redox dye reduction. A typical example is a combination of redox dye MTS (Promega) and the electron coupling reagent PES. This mixture is made up according to the manufacturer's instructions and left at room temperature.

9) Add lOμL/well MTS/PES solution to the cells; mix and leave at 37°C.

10) Read plate when the absorbance values are approximately 0.4 — 0.8. (Mix briefly before reading to disperse the reduced formazan product).

11) Quantitate amyloid beta 40 peptide using an HTRF plate reader. Alternative assays are described in Biochemistry, 2000, 39(30), 8698-8704.

See also, J. Neuroscience Methods, 2000, 102, 61-68. The Examples of the present invention all had an ED50 of less than lμM, typically less than 0.5μM, in most cases less than lOOnM, and in preferred cases less than lOnM, in at least one of the above assays. The following examples illustrate the present invention.

Examples

Intermediate A: 4-[(4-Chlorophenyl)sulfonyl1'4-(2,5-difluorophenyl) cyclohexanone

Prepared as described in WO 02/081435 (Example 2).

Intermediate B: [4-(4-Chloro-benzenesulfonyl)-4-(2,5-difluoro-phenyl)- cyclohexyl] -acetic acid ethyl ester

Prepared as described in WO 02/081435 (Example 48).

Intermediate C: [4-(4-Chlorophenylsu^'lfonyl)-4-(2₁5-difluoro-phenyl)- cyclohexyl] -acetic acid

Prepared as described in WO 02/081435 (Example 50).

Intermediate D: 2-[4-(4-Chloro-benzenesulfonyl)-4-(2,5-difLuoro-phenyl)- cyclohexyl] -ethanol

To Intermediate C (l g, 2.3 mmol) in dry tetrahydrofuran (80 mL) at 0°C under nitrogen were added triethylamine (0.4 mL, 2.8 mmol) and iso- butylchloroformate (0.36 mL, 2.8 mmol). The reaction was stirred for 1.5 h, filtered, the filtrate re -cooled to 0°C and sodium borohydride (435 mg, 11 mmol) in water (10 L) added drop wise. After stirring at 0°C for 1 h the reaction was concentrated, diluted with ethyl acetate, washed with water and brine and then dried (MgS0₄), filtered and evaporated. The residue was purified by flash column chromatography on sihca, eluting with iso- hexane/ethyl acetate (i:i), to give the alcohol as a white sohd (960 mg

Intermediate E: Iodo-[4-(4-Chloro-benzenesulfonyl)-4-(2,5-difluoro- phenyQ-cyclohexyl] -methane

A stirred solution of Intermediate C (6.85 g, 16.0 mmol.), iodosobenzene diacetate (14.4 g, 44.7 mmol.) and iodine (6.20 g, 24 mmol.) in dry benzene (200 mL) was heated to reflux under irradiation by a 250W tungsten lamp. After 45 minutes, further iodosobenzene diacetate (3.0 g, 9.3 mmol.) and iodine (1.5 g, 5.8 mmol.) were added and reflux under irradiation continued for a further lh. The reaction was cooled and diluted with ethyl acetate (200 mL) then washed with aqueous sodium thiosulfate (10%, 2 x 200 mL), water (200 mL), aqueous sodium hydroxide solution (1M, 200 mL) and brine (200 mL) then dried (MgS0₄) and evaporated to leave a residue which was purified by flash column chromatography on sihca, eluting with ether dichloromethane :iso -hexane (l:i:8), to afford iodo-[4-(4-chloro-benzenesulfonyl)-4-(2,5-difluoro-phenyl)- cyclohexyl] -methane (6.00 g, 74%). Intermediate F: 2-Iodo-[4-(4-Chloro-benzenesulfonyl)-4-(2,5-difluoro- phenyl)-cvclohexyl] -ethane

A solution of Intermediate D (414 mg, 1 mmol), imidazole (272 mg, 4 mmol) and triphenylphosphine (524 mg, 2 mmol) in toluene (15 mL) was stirred at room temperature for 10 minutes, then iodine (279 mg, 1.1 mmol) was added. The reaction was stirred at ambient temperature for 2.5h then at 65°C for lh. Upon coohng, the mixture was decanted and evaporated to dryness. The residue was extracted into ether (3 x 50 mL) and the combined organics evaporated then filtered through a plug of silica, eluting with ether :iso -hexane (1:4) to give_. the desired iodide (252 mg).

Intermediate G: 4-(4-Chloro-benzenesulfonyl)-4-(2, 5-difluoro-phenyl)- cyclohexanol

A solution of Intermediate A (10.05 g, 26 mmol) in tetrahydrofuran (200 mL) cooled to -78°C was treated with L-Selectride™ (1.0 M solution in tetrahydrofuran, 31.4 mL, 31.4 mmol). After stirring at -78°C for 2 hours the reaction was quenched with aqueous hydrochloric acid (2M). The solvent was evaporated and the product extracted into ethyl acetate and washed with water followed by brine, and evaporated to an oil which was purified by flash chromatography eluting with ethyl acetate :hexane 1:1 to afford the desired intermediate (6g).

Intermediate H: 2-[4-(4-Chloro-benzenesulfonyl)-4-(2,5-difluoro-phenyl)- cvclohexyl]-N-methoxy-N-methyl-acetamide

Prepared as described in WO 02/081435 (Example 219).

Intermediate I: [4-(4'Chloro-benzenesulfonyl)-4-(2,5-difluoro-phenyl)- cyclohexyl] -methane thiol

To a solution of Intermediate E (2.05 g, 4.0 mmol.) in N,N- dime thy lformamide (80 mL) was added potassium thioacetate (2.3 g, 20 mmol.) and the solution stirred for 2h. at ambient temperature then diluted with water (100 mL) and extracted into ether (2 x 100 mL). The combined organic layers were washed with water (3 x 100 mL) and brine (100 mL), dried (MgS0₄) and evaporated to leave the crude thioacetic acid 4-(4-chloro-benzenesulfonyl)-4-(2,5-difluoro-phenyl)-cyclohexylmethyl ester (1.81 g). This was dissolved in methanol (80 mL), 1M aqueous sodium hydroxide solution (20 mL) was added and the mixture vigorously stirred for lh. Water (50 mL) was added and the mixture extracted into ethyl acetate (2 x 100 mL). The combined organic layers were washed with water (100 mL) and brine (100 mL), dried (MgS0 ) and evaporated to leave a residue of the desired thiol (l.65g, quant.).

Intermediate J: C-[4-(4-Chloro-benzenesulfonyl)-4-(2,5-difluoro-phenyl)- cyclohexyl] -methylamine

To a stirred solution of Intermediate C (75 mg, 0.18 mmol.) in tetrahydrofuran (10 mL) was added oxalyl chloride (0.02 mL, 0.23 mmol.) -and N, A^dimethylformamide (l drop) and the mixture stirred at ambient temperature for 90 minutes then evaporated. Toluene (10 mL) was added then evaporated and the residue taken up in benzene (2 mL) and cooled in an ice bath. A solution of tetrabutylammonium bromide (l mg) and sodium azide (23 mg, 0.36 mmol.) in water (1 L) was added, the cooling bath removed and the mixture allowed to stir at ambient temperature for 2 hours. The layers were separated and the organic phase washed with brine (10 mL), dried (MgS0₄) and filtered. Benzyl alcohol (0.1 mL) was added and the mixture heated to reflux for 18 hours then cooled and diluted with ethyl acetate (10 mL), washed with water (10 mL) and brine (10 mL), dried (MgSθ4) and evaporated to leave a residue which was purified by flash column chromatography on sihca, eluting with ethyl acetate :iso -hexane (1:3), to afford the desired benzyl carbamate (60mg). MS (ES+) 534 ([MH]⁺).

To the foregoing carbamate (40 mg, 0.08 mmol.) was added hydrobromic acid (l L of a 45% w/v solution in acetic acid). The reaction was stirred for 90 minutes, diethyl ether- (10 mL) and water (10 mL) added, the organic phase washed with aqueous hydrochloric acid (2N, 10 mL), the combined aqueous phases basified to pH 12 with 4N aqueous sodium hydroxide solution then extracted into ethyl acetate (2 x 10 mL). The combined organic layers were dried (MgSθ₄) and evaporated to give the primary amine intermediate (26 mg) which was used without further purification.

Intermediate K: 4-(2,5-Difluoro-phenyl)-4-(4-trifluoromethyl- benzenesulfonyQ-cyclohexanone

Prepared as described in WO 02/081435 (Example 41).

Intermediate L: [4-(2,5-Difluoro-phenyl)-4-(4-trifluoromethyl- benzenesulfonyl)-cyclohexyl]-acetic acid

Prepared as described in WO 02/081435 (Example 232).

Intermediate M: Iodo-[4-(2,5-Difluoro-phenyl)-4-(4-trifluoromethyl- benzenesulfonyl)-cvclohexyl]-methane

Prepared from Intermediate L by the method of Intermediate E Intermediate N: 2-[4-(2,5-Difluoro-phenyl)-4-(4-trifluoromethyl- benzenesulfonyl)-cyclohexyl]-ethanol

Intermediate L (14.1 g, 0.031 mol) in tetrahydrofuran (250 mL) was treated with triethylamine (5.1 L, 0.036 mol) and ⁱbutylchloroformate (4.64 mL, 0.036 mol) at 0°C. After stirring for 1.5 hours, the precipitate was filtered off and the filtrate re -cooled to 0°C, before being treated with sodium borohydride (l.9g, 0.05 mol) in water (10 mL) and stirred for 1 hour. The reaction was concentrated, diluted with ethyl acetate and washed with water and brine. The separated organic phase was dried over magnesium sulfate, filtered and evaporated to dryness. The alcohol was purified by sihca gel chromatography eluting with ethyl acetate and hexane mixtures to give 11.5g.

Intermediate Q: 4-(2,5-Difluoro-phenyl)-4-(4-trifluoromethyl- benzene sulfonyl) -cy clohexanol

Prepared from Intermediate K by the method of Intermediate G. Intermediate P: Methanesulfonic acid 2-[4-(2,5-difluoro-phenyl)-4-(4- trifluoromethyl-benzenesulfonyl) -cyclohexyl] -ethyl ester

Intermediate N (3.80 g, 8.48 mmol) and triethylamine (1.17 mL) in dichloromethane (150 mL) was treated dropwise with mesyl chloride, maintaining the internal temperature below -40°C. After complete addition the reaction was allowed to warm to room temperature and stirred for 1 hour. The reaction mixture was washed with water (50 mL), 10% aqueous citric acid (50 L) and saturated sodium bicarbonate solution (50 mL) then dried over magnesium sulfate. After evaporation to dryness, the product was triturated with diethyl ether to give 4.2g.

Intermediate Q: [4-(4-chloro-benzenesulfonyl)-4-(2,5-difluoro-phenyl)- cyclohexyl] -methanesulfonyl chloride

Intermediate I (1.65 g, 4.0 mmol.) in acetonitrile (120 mL) was cooled to 0°C under nitrogen. Potassium nitrate (1.01 g, 10 mmol.) then sulfuryl chloride (0.80 mL, 10 mmol.) were added, the mixture stirred at 0°C for 2 hours, then diluted with a saturated aqueous solution of sodium hydrogencarbonate (100 mL). The mixture was extracted into ethyl acetate (2 x 100 mL) and the combined organics washed with saturated aqueous sodium hydrogencarbonate (100 mL) and brine (100 mL), dried (MgS0 ) and evaporated to leave a residue which was purified by column chromatography on silica, eluting with diethyl ether : iso-hexane (l^:2), to afford the title compound as a colourless sohd (0.81g).

Intermediate R: 4-[(4-Chlorophenyl)sulfonyl]-4-(2,5- difluorophenvOcyclohexylamine

Prepared as described in WO 02/081435 (Example 39).

Intermediate S: 4-(2.5-Difluorophenyl)-4-(4- trifluoromethylbenzenesulfonyl)-cyclohexylamine

Prepared as for Intermediate R, using Intermediate K, except that the borohydride reduction was carried out at -20°C. MS (ES+) MH+ 420

Intermediate T: 4-(2,5-Difluorophenyl)-4-(6-trifluoromethyl-pyridine-3- sulfonyl)-cyclohexylamine

(l) A solution of 3-amino-6-(trifluoromethyl)pyridine (1.62 g, 0.01 mol) in concentrated hydrochloric acid (1.7 mL), was treated with ice (2 g) and cooled to 0°C. Sodium nitrite (0.71 g, 0.01 mol) in water (2 mL) was added slowly, the reaction mixture stirred for 5 minutes at 0°C then treated slowly with a solution of potassium ethyl xanthate (1.92 g, 0.012 mol) in ethanohwater. The reaction mixture was heated at 50-55°C for 30 minutes, cooled and diluted with diethyl ether and water. The organic layer was washed with brine, dried (MgS0₄) and evaporated in vacuo. The resulting xanthate was dissolved in ethanol (30 mL) and treated with potassium hydroxide (3 g) and refluxed (90°C) for 2 h. After coohng and filtering, the filtrate was acidified with citric acid and diluted with diethyl ether. The organic layer was washed with brine, dried (MgSθ4)*and evaporated in vacuo. Purification by column chromatography on sihca gave the (trifluoromethyl)pyridinethiol as a yellow oil (0.79 g, 44%). (2) This thiol (0.5 g, 2.8 mmol) was reacted first with 2,5-difluorobenzyl bromide and subsequently with 3-chloroperoxybenzoic acid by the procedure described for Intermediate 1 in WO 02/081435 to gave the pyridyl benzyl sulfone as a white powder (0.82 g, 87% over 2 steps). (3) This sulfone (50 mg, 0.15 mmol) in tetrahydrofuran (5 mL) at 0°C was treated with potassium fertrbutoxide (17 mg, 0.15 mmol), then with 2,2-bis(2-iodoethyl)-l,3-dioxolane (H. Niwa et al, J. Am. Ghem. Soc, 1990, 112, 9001) (86 mg, 0.23 mmol), stirred for 1 h at room temperature and then for 1 h at 70°C. The cooled reaction mixture was treated with more potassium fertrbutoxide (1.2 equivalents) and 2,2-bis(2-iodoethyl)-l,3- dioxolane (0.3 equivalents). After heating at 70°C for lh, then coohng to room temperature, the reaction mixture was diluted with diethyl ether and water, the layers separated and the organic layer washed with water and brine, dried (MgSθ4) and evaporated in vacuo. Purification by column chromatography on sihca gave the desired cyclohexanone cyclic ketal (38 mg, 56%) as a white solid. (4) This ketal (30 mg, 0.065 mmol) was heated at 50°C overnight with -toluenesulfonic acid (15 mg) in 80% acetic acid -water. The reaction mixture was partitioned between diethyl ether and water and the organic layer washed with saturated aqueous sodium hydrogencarbonate solution and brine, dried (MgS0₄) and evaporated in vacuo. Purification by column chromatography on silica gave the cyclohexanone (25 mg, 92%) as a white sohd.

(5) The cyclohexanone was converted to the title amine by the procedure of Intermediate R, except that the borohydride reduction was carried out at -78°C. M/Z 421 (MH⁺).

Example 1- C-[4-(4-Chloro-benzenesulfonyl)-4-(2,5-difluoro-phenyl)- cyclθhexyl]-N-phenyl-methanesulfonamide

Prepared from Intermediate Q and excess aniline by refluxing in tetrahydrofuran under nitrogen. MS (ES+) 562 ([MNa]+).

Example 2- [4-(2,5-Difluoro-phenyl)-4-(4-trifluoromethyl- benzenesulfonyl) -cyclohexyl] -methanesulfonamide

Intermediate M (650 mg, 1.3 mmol) was converted to the corresponding thiol and then to the corresponding sulfonyl chloride by the methods of Intermediate I and Intermediate Q. (Yield 365 mg white solid). This was dissolved in dichloromethane (30 mL) and ammonia gas bubbled into the solution until saturation. The reaction was stirred for a further 30 min before filtering through Celite^®. After concentration, the residue was purified by flash chromatography on silica, eluting with isσ-hexane/ethyl acetate (l^:l), to give the sulfonamide as a white solid (150 mg). MS (ES+) 498 ([MH]⁺).

Examples 3- 33

The sulfonamides in examples 3-33 were prepared from Intermediate Q by treatment with the appropriate amine in dichloromethane. The reaction was diluted with ethyl acetate, washed with 2N HCl and brine, dried

(MgSθ4) and evaporated to leave a residue which was purified by column chromatography on sihca. In cases where a salt of the required amine is used, a=base, for example pyridine or potassium carbonate, may be added.

(a) - hydrolysis of Ex. 18, 19 or 29 using LiOH in aqueous THF.

(b) - treatment of Ex. 20 with trifluoroacetic acid in dichloromethane.

(c) — coupling of Ex. 27 with acetic acid using dimethylaminopyridine and l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride in dichloromethane .

(d) — oxidation of Ex.30 using Dess-Martin periodinane in dichloromethane at ambient temperature.

(e) - treatment of Ex. 31 with MeMgBr in THF at ambient temperature.

(f) - treatment of Ex. 30 with methanesulfonyl chloride and triethylamine in dichloromethane at 0°C. Example 34: 2-[4-(4-Chloro-benzenesulfonyl)-4-(2,5-difluoro-phenyl)- cvclohexylmethylsulfanyl] -pyridine

To a stirred solution of Intermediate E (150 mg, 0.29 mmol) in ethanol (10 mL) under nitrogen was added potassium hydroxide (18 mg, 0.32 mmol) and 2-mercaptopyridine (36 mg, 0.32 mmol). The mixture was stirred and heated to reflux for 16 hours. After cooling, the reaction was diluted with water and extracted with ethyl acetate. The combined organic layers were washed with water and brine, dried (MgS04) and evaporated to leave a residue (154 mg) which was purified by preparative thin layer chromatography eluting with ethyl acetate: iso-hexane 1:6 to afford the desired product (118 mg). MS (ES+) 494 (CMH]⁺), 318 ([M-ArS0₂-]⁺).

Example 35: 2-[4-(4-Chloro-benzenesulfonyl)-4-(2,5-diflύoro-rhenyl)- cyclohexylmethanesulfonyl]-pyridine

To a stirred solution of the product from Example 34 (40 mg, 0.081 mmol) in dichloromethane (10 mL) under nitrogen was added 3- chloroperoxybenzoic acid (62 mg, 50-55% w/w in water, 0.18 mmol). The mixture was stirred at ambient temperature for 18h. The reaction was diluted with dichloromethane, washed with sodium sulfite solution and brine, dried (MgSθ4) and evaporated to afford the desired product (56 mg). MS (ES+) 526 ([MH]⁺), 350 ([M-ArS0₂-]⁺), 548 ([MNa]⁺). Example 36 2-[4-(4-Chloro-benzenesulfonyl)-4-(2,5-difluoro-phenyl)- cvclohexylmethanesulfinyl] -pyridine

Prepared by oxidation of Example 34 by the method of Example 35 using one equivalent of 3-chloroperoxybenzoic acid.

MS (ES+) 510 ([MH]⁺), 334 ([M-ArS0₂-]⁺), 532 ([MNa]⁺).

Example 37: 2-[4-(4-Chloro-benzenesulfonyl)-4-(2,5-difluoro-phenyl)- cvclohexylmethanesulfonvU-pyridine-A^oxide

Prepared from Example 35 by treatment with urea hydrogen peroxide (2 equivalents) and trifluoroacetic anhydride (2 equivalents) in dichloromethane at 0°C. MS (ES+) 542 ([MH]⁺), 366 (DvI-ArS0₂-]+).

Example 38: l-(4-Chlorophenylsulfonyl)-l-(2.5-difluoro-phenyl)-4-[(2- propyl)sulfonylmethyl]-cyclohexane

Intermediate E (150 mg, 0.29 mmol) was reacted with 2-propanethiol (30 μL, 0.32 mmol) by the method of Example 34. The resulting sulfide, in ethyl acetate (l mL), was added to a stirring solution of sodium periodate (139 mg, 0.65 mmol) in a 1:2 solution of ethyl acetate "-water (3 mL) and a catalytic amount of ruthenium (IV) oxide. The reaction mixture was stirred at ambient temperature over 30 min., diluted with water, extracted with ethyl acetate, washed with brine, dried (MgSθ4) and evaporated to give a residue (135 mg) which was purified by preparative thin layer chromatography eluting with ethyl acetate :iso -hexane 1:3 to afford the desired product (39 mg). MS (ES+) 513 ([MNa]⁺), 508 ([MNH₄]⁺).

Examples 39-75. 78-90

In the following examples, Intermediate E or Intermediate M was reacted with the appropriate thiol as in Example 34 and (where necessary) oxidised as in Example 35 (Method A) or as in Example 38 (Method B), or as in Example 36 (Method C).

nd = not determined

(a) -2-mercaptoethyl acetate as thiol; treatment with MeMgBr in THF prior to oxidation.

(b) - 2-mercaptoethanol as thiol; O-methylation (Mel, NaH, DMF) prior to oxidation.

(c) - thiol prepared by reaction of cycloalkylMgBr with sulfur then LiAUEU in THF.

(d) - via alkylation of Ex. 61 (Mel, K₂Cθ3,DMF) then chromatographic separation of 1:1 mixture of positional isomers on sihca! Ex. 66 the more polar isomer.

(e) — via hydrolysis of corresponding ester (LiOH in aqueous MeOH). Example 76: l-(4-Trifluoromethylphenylsulfonyl)-l-(2.5-difluoro- phenyl)-4-methanesulfonylmethyl-cyclohexane

To Intermediate M (240 mg, 0.42 mmol) in ethanol (8 mL) was added sodium methanesulfinate (136 mg, 1.33 mmol). The reaction was refluxed for 18 h and after cooling was diluted with water, and extracted with ethyl acetate (x3). The organic extracts were washed with water and brine, dried (M Sθ4) and evaporated. The residue was purified by flash chromatography on silica eluting with ethyl acetate to give the title compound (80 mg). MS (ES+) 519 ([MNa]⁺).

Example 77: 2-[4-(4-Chloro-benzenesulfonyl)-4-(2.5-difluoro-phenyl)- cyclohexylmethanesulfonyl]-acetamide

Prepared from Example 75 by treatment with pentafluorophenol and dicyclohexylcarbodiimide in ethyl acetate at0°C, then treatment with ammonia (2M in methanol) at 50°C in a sealed tube for 16 h. MS (ES+) 506 (DvIH]⁺). Example 91- [4-(4-Chloro-benzenesulfonyl)-4-(2,5-difl.uoro-phenyl)- cyclohexyl]-methylisothiocyanate

To a stirred solution of Intermediate E (118 mg, 0.23 mmol) in N,N- dimethylformamide (10 mL) was added potassium isothiocyanate (112 mg, 1.05 mmol) and the mixture warmed to 80°C for 18 hours. Upon cooling, ethyl acetate (20 mL) was added and the solution washed with water (3 x 20 mL) and brine (20 mL), dried (MgS0₄) and evaporated to leave a residue which was purified by flash column chromatography on silica, eluting with diethyl ether :iso -hexane 1:3, to afford the desired product (89 mg, 0.18 mmol.). MS (ES⁺) 459 ([MNH₄]⁺X

Example 92: {[4-(4-chloro-benzenesulfonyl)-4-(2,5-difluoro-phenyl)- cyclohexyl] -methylj-trifluoromethyl sulfone

The product from Example 91 (80 mg, 0.18 mmol) in tetrahydrofuran (5 mL) at 0°C was treated with trimethyl(trifluoromethyl)silane (0.055 mL, 0.36 mmol) tetrabutylammonium fluoride (0.04 mL of a 1M solution in tetrahydrofuran, 0.04 mmol) and the mixture stirred for 5 minutes at 0°C then 3 hours at room temperature. Diethyl ether (20 mL) was added and the solution washed with water (2 x 20 mL) and brine (20 mL), dried (MgS0₄) and evaporated to leave a residue which was purified by flash column chromatography on silica eluting with diethyl ether :iso-hexane 1:3, to afford {[4-(4-chloro-benzenesulfonyl)-4-(2,5-difluoro-phenyl)-cyclohexyl]- methyl}-trifluoromethyl sulfide (49 mg,). Of this, 47 mg (0.1 mmol) was oxidised to the sulfone by the method described in Example 38. Final purification was by flash column chromatography on silica eluting with diethyl ether :iso -hexane 1:2, to afford the desired product (38 mg). MS (ES⁺) 534 ([MNH₄]⁺X

Example 93: 2-[4-(4-Chloro-benzenesulfonyl)-4-(2,5-difluoro-phenyl)- cyclohexylmethanesulfonyl] -furan

To a solution of furan (0.043 mL, 0.67 mmol) in tetrahyrofuraϊi (5 mL) at -40°C under nitrogen was added n-butyl lithium (0.41 mL of a 1.6M solution in hexanes, 0.66 mmol) and the reaction allowed to attain room temperature over 1 hour. Upon recoohng to 0°C, sulfur (6 g, 0.19 mmol) was added and the reaction stirred for 30 minutes at 0°C before a solution of Intermediate E (100 mg, 0.20 mmol) in ethanol (5 mL) Was added. The mixture was then warmed to 60°C for 75 minutes, cooled, quenched by the addition of a saturated aqueous solution of ammonium chloride (20 mL), then extracted into ethyl acetate (2 x 30 mL). The combined organics were washed with water (2 x 10 mL) and brine (20 mL), dried (M S04) and evaporated to leave a residue of the crude furan thioether (102 mg). This was oxidised to the sulfone by the method described in Example 38. Final purification was by flash column chromatography on silica, eluting with diethyl ether:iso-hexane 1:1, to afford the desired product (26 mg). MS (ES⁺) 532 ([MNH₄]⁺X Example 94'- l-(4-Chlorophenylsulfonyl)~l-(2,5-difluoro-phenyl)-4- methanesulfonylmethylene-cvclohexane

To a stirred solution of diisopropylamine (0.72 mL, 5.2 mmol) in tetrahydrofuran (40 mL) at -78°C was added dropwise a solution of n- butyl lithium (1.6M in hexanes, 3.2 L, 5.1 mmol). The mixture was allowed to warm briefly to room temperature then recooled to — 78°C and dimethyl sulfone (470 mg, 5.1 mmol) in tetrahydrofuran (10 mL) added dropwise. After stirring for 20 minutes at -78°C, Intermediate A (640 mg, 1.67 mmol) in tetrahydrofuran (lO mL) was added and stirring continued for a further 1 hour. The reaction was quenched by the addition of saturated aqueous ammonium chloride (50 mL), allowed to warm to room temperature then extracted into ethyl acetate (2 x 50 mL). The combined organics were washed with 2N aqueous hydrochloric acid (2 x 50 mL) and brine (50 mL), dried (MgSθ4) and evaporated to leave a residue which was purified by flash column chromatography on silica, eluting with. ethyl acetate :iso -hexane l^'-l, to afford 4-(4-chloro-benzenesulfonyl)-4:(2,5- difluoro-phenyl)-l-methanesulfonylmethyl-cyclohexanol (630 mg). MS (ES⁺) 496 ([MNH ]⁺). The alcohol from the foregoing step (420 mg, 0.88 mmol) in dichloromethane (20 mL) was cooled to 0°C under nitrogen and triethylamine (0.25 mL, 1.7 mmol) and methane sulfonyl chloride (0.1 mL, 1.3 mmol) were added. The reaction was stirred for 1 hour at 0°C then further triethylamine (0.5 mL, 3.4 mmol) and methane sulfonyl chloride (0.21 mL, 2.7 mmol) added. After a further 30 minutes, the solution was washed with 2N aqueous hydrochloric acid (2 x 10 mL) and brine (10 mL), dried (MgSθ4), evaporated and the residue taken up in tetrahydrofuran (20 mL). l,8-diazabicyclo[5.4.0]undec-7-ene (0.26 mL, 1.7 mmol) was added and the mixture stirred for 5 minutes. Ethyl acetate (30 mL) was added, the solution washed with IN aqueous sodium hydroxide (20 mL), and the aqueous layer extracted with further ethyl acetate (10 mL). The combined organic layers were washed with 2N aqueous hydrochloric acid (20 mL) and brine (20 mL), dried (MgS0₄) and evaporated to leave a residue which was purified by flash column chromatography on silica eluting with ethyl acetate :iso -hexane 1:1, to afford the desired product (196 mg). MS (ES⁺) 478 ([MNH₄]⁺X

Example 95: l-(4-Chlorophenylsulfonyl)-l-(2,5-difluoro-phenyl)-4- methanesulfonylmethyl-cyclohexane

The product of Example 94 (150 mg, 0.32 mmol) in tetrahydrofuran (20 mL) at — 40°C was treated dropwise with L-Selectride™ (IM solution in tetrahydrofuran, 0.5 mL, 0.5 mmol). The reaction was stirred at -40°C for 90 minutes, then quenched by the addition of ethanol (4 drops) then water (10 mL). The mixture was extracted into ethyl acetate (2 x 50 mL) and the combined organics washed with brine (50 mL), dried (MgSθ4) and evaporated to leave a residue which was purified by flash column chromatography on silica eluting with diethyl ether ^"-dichlorome thane :iso - hexane 1:2:1, to afford the desired product (107 mg). MS (ES⁺) 480 ([MNH₄]⁺X Example 96: l-(4-Chlorophenylsulfonyl)-l~(2,5-difluoro-phenyl)-4- phenylsulfonylmethyl-cvclohexane

Prepared as in Example 76 using Intermediate E, sodium phenylsulfinate and DMF as solvent. MS (ES+) 542 ([MNH₄]⁺).

Example 97: l-(4-Chlorophenylsulfonyl)-l-(2.5-difluoro-phenyl)-4- [(cyanomethyl)sulfonylmethyl]-cyclohexane

To a stirred solution of Intermediate I (120 mg, 0.29 mmol) in acetonitrile (5 mL) was added potassium carbonate (41 mg, 0.30 mmol) and a solution of chloroacetonitrile (0.04 mL, 0.64 mmol) in acetonitrile (10 mL) and the reaction warmed to 50°C for 2 hours. Upon cooling, the mixture was filtered and the filtrate evaporated. The residue was taken up in ethyl acetate (3 mL) and oxidised to the sulphone by the method described in Example 83. Finalpurification was by flash column chromatography on sihca eluting with diethyl ether :iso -hexane 1:1, to afford the desired product (51 mg). MS (ES ) 486 ([M-H]^"). Example 98: l-(2,5-Difluoro-phenyl)-l-(4-trifluoromethylphenylsulfonyl)-

4-propylsulfonylethyl-cyclohexane

A stirred solution of Intermediate P (0.115 g, 0.22 mmol), 1-propanethiol (0.021 mL, 0.22 mmol) and powdered potassium hydroxide (0.015 mg, 0.26 mmol) in ethanol (5 mL) was heated at reflux for 45 minutes, then evaporated. The residue was dissolved in diethyl ether (25 mL), washed with brine (20 mL), dried over magnesium sulfate and evaporated to dryness.

The resulting crude thioether in dichloromethane (10 mL) was oxidised as described in Example 35. MS (ES+) 539 ([MH]⁺X

Examples 99 to 102 were prepared from Intermediate P by the method of Example 98 using the appropriate thiol.

Example 103 : l-(4-Chlorophenylsulfonyl)- 1-(2, 5-difluoro-phenyl)-4- [2- (methylsulfonyl)ethyl]-cyclohexane

Prepared from Intermediate F and sodium methylsulfinate by the method of Example 96. MS (ES+) 499 ([MNa]⁺X

Example 104: 2-[4-(4-Chloro-benzenesulfonyl)-4-(2,5-difluoro-phenyl)- cyclohexyl]-ethanesulfonic acid amide

Intermediate D (5.09 g, 12.3 mmol) was converted to the mesylate following the procedure of Intermediate P.

The foregoing mesylate (1.18 g, 2.4 mmol) was converted to the thiol foUowing the procedure of Intermediate I. This product was converted to the sulfonyl chloride by the procedure of Intermediate Q, which was dissolved in dichloromethane (10 ml) and ammonia gas bubbled through for 5 minutes. The resulting cloudy solution was stirred at ambient temperature for 15 minutes then evaporated and taken up in ethyl acetate (20 mL), washed with water (20 ml) and brine (20 mL), dried (MgS0₄) and evaporated to leave a residue which was triturated with diethyl ether to afford the desired product (51 mg) MS (ES+) 500 ([MNa]⁺). Example 105: 2-[4-(4-Chloro-benzenesulfonyl)-4-(2,5-difluoro-phenyl)- cyclohexyU'ethanesulfonic acid acetyl-amide

Prepared from Example 104 by coupling with acetic acid in the presence of l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and dimethylaminopyridine in dichloromethane. MS (ES+) 542 ([MNa]⁺X

Example 106: 2-[4-(4-Chloro-benzenesulfonyl)-4-(2,5-difluoro-phenyl)- cyclohexyl]-ethanesulfonic acid tert-butylamide

Prepared by coupling [4-(4-chloro-benzenesulfonyl)-4-(2,5-difluoro-phenyl)- cyclohexyl]-ethanesulfonyl chloride (see Example 104) with tertr butylamine in dichloromethane (5mL). MS (ES+) 556 ([MNa]⁺X

Example 107: 4-[4-(4-Chloro-benzenesulfonyl)-4-(2,5-difluoro-phenyl)- cyclohexyl]-2-methanesulfonyl-butyric acid ethyl ester

Ethyl methanesulfonylacetate (0.285 mL, 2.15 mmol) was added dropwise to a solution of sodium hydride (60% dispersion in mineral oil, 94 mg, 2.37 mmol) in N,N- dimethylformamide (7.0 L) at 0°C. The reaction was stirred at 0°C for one hour, before the addition of Intermediate F (1.13 g, 2.15 mmol) in A A^dimethylformamide (2 mL). The reaction was stirred at 0°C for a further 2 hours, then for a furtherl2 hours, warming gradually. The reaction was partitioned between diethyl ether (150 mL) and IM aqueous hydrochloric acid (150 mL), the phases separated and the aqueous layer washed with diethyl ether. The combined organic layers were washed with IN aqueous sodium hydrogencarbonate and brine, dried over MgSθ4 and concentrated. The residue was chromatographed using a Biotage™ 40S column, eluting with 70/30 iso -hexane/ace tone to give the title compound (769 mg). MS (ES-) 561 ([M-H] ).

Example 108: 3-[4-(4-Chloro-benzenesulfonyl)-4-(2.5-difluoro-phenyl)- cyclohexyl]-2-methanesulfonyl-propionic acid ethyl ester

Prepared by the procedure of Example 107 using Intermediate E. MS (ES-) 547 ([M-H] ).

Example 109: 4-[4-(4-Chloro-benzenesuIfonyl)-4-(2,5-difLuoro-phenyl)- cyclohexyl]-2-ethyl-2-methanesulfonyl-butyric acid ethyl ester

Prepared from Example 107 by alkylation with ethyl trifluoromethanesulfonate using NaH in dimethylformamide. MS (ES-) 589 ([M-H] ). Example llQ: 4-[4-(4-Chloro-benzenesulfonyl)-4-(2,5-difluoro-ρhenyl)- cyclohexyl]-2-ethyl-2-methanesulfonyl-butyric acid

The product of Example 109 was hydrolyzed by heating to 50°C with LiOH in aqueous THF, followed by extractive work-up. MS (ES-) 561 ([M-H] ).

Example 111: l-(4-Chlorophenylsulfonyl)- 1-(2, 5-difl uoro-phenyl)-4- [(3- sulfonylmethyl)pentyl]-cvclohexane

Prepared from Example 110 by refluxing with excess sodium chloride in 58% aqueous dimethylsulfoxide for 26 hours. MS (ES+) 519 ([MH]⁺).

Example 112: (2.2.2-Trifluoro-ethyl)-sulfamic acid 4-(2.5-difluoro- phenyl)-4-(4-trifluoromethyl-benzenesulfonyl)- cyclohexyl ester

Prepared from Intermediate O by treatment with trifluoroethyl sulfamoyl chloride and triethylamine in dry dichloromethane under nitrogen. Example 113: acetic acid 2-[4-(4-chloro-benzenesulfonyl)-4-(2,5-difluoro- phenyl)-cvclohexyloxysulfonylamino] -ethyl ester

Prepared by treatment of Intermediate G by treatment with 2- acetoxyethylsulfamoyl chloride and triethylamine in N,N- dimethylacetamide at 60°C. MS (ES+) 574 ([MNa]⁺X The sulfamoyl chloride was obtained from reaction of 2-aminoethyl acetate hydrochloride with sulfuryl chloride in acetonitrile.

Example 114: (2-Hydroxy-ethyl)-sulfamic acid 4-(4-chloro- benzenesulfonyl)-4-(2,5-difluoro-phenyl)-cyclohexyl ester

Prepared from Example 113 by hydrolysis with LiOH in aqueous tetrahydrofuran. MS (ES+) 510 (DVIH]⁺).

Example 115: Sulfmamic acid 4-(4-chloro-benzenesulfonyl)-4-(2,5- difluoro-phenyl)-cyclohexyl ester

Prepared from Intermediate G by treatment with thionyl chloride and pyridine in dichloromethane at — 78°C and subsequently with ammonia gas, also at — 78°C. was bubbled through keeping the temperature at — 78°C. After 20 minutes, the reaction vessel was sealed and left to stir for 19 hours slowly warming to room temperature. MS (ES-) 448 ([M-H] ).

Examples 116-12Q:

Prepared from Intermediate G or Intermediate O by the procedure of Example 113, carried out at ambient temperature.

Example 121: Dimethyl-sulfamic acid 4-(4-chloro-benzenesulfonyl)-4- (2,5-difl.uoro-phenyl)-cyclohexyl ester

Prepared from Example 116 by alkylation with excess Mel in tetrahydrofuran cooled to -78°C using lithium bis (trime thy lsilyl) amide (IM solution in tetrahydrofuran) as base. MS (ES+) 516 ([MNa]⁺X

Example 122: Acetyl-sulfamic acid 4-(4-chloro-benzenesulfonyl)-4-(2.5- difhioro-phenyQ-cyclohexyl ester

Prepared from Example 116 by treatment with acetic anhydride in pyridine at room temperature. MS (ES+) 530 ([MNa] ).

Example 123: Sulfamic acid 4-(2,5-diflιιoro-phenyl)"4-(6-trifluoromethyl- pyridine-3-sulfonyl)-cyclohexyl ester

4-(2,5-Difluoro-phenyl)-4-(6-trifluoromethyl-pyridine-3-sulfonyl)- cyclohexanone (Intermediate T, steps 1-4) was reduced to the cis- cyclohexanol using L-Selectride™ (IM in tetrahydrofuran) as described for

Inermediate G

This alcohol was treated with sulfamoyl chloride as in Examples 116-120 to give the desired product as a white sohd. MS (ES+) 501 ([MH]⁺X Examples 124-127. 129. 147-15Q:

The following were prepared from Intermediate H by reaction with ArMgBr in THF at 0°C.

(a) - starting from the 2-allyloxy derivative. Cleavage to the phenol occurred in situ, and this was alkylated with the relevant chloroester.

(b) - hydrolysis of corresponding ester as final step.

(c) — cleavage of the corresponding 1,3-dioxolan as final step (pyridinium p- toluenesulfonate in aqueous acetone).

(d) - oxidation of corresponding aldehyde as final step (using Dess-Martin periodinane). Example 128: 2-[4-(4-Chloro-benzenesulfonyl)-4-(2,5-difluoro-phenyl)- cyclohexyl]-l-{3-[2-(l.l-dioxo-thiomorpholin-4-yl)-ethoxy]-phenyl}- ethanone

The product from Example 125 was treated with ozone in 1:5 methanol:dichloromethane under nitrogen at -78°C to form the corresponding aldehyde. This aldehyde and 1,1-dioxothiomorphohne in methanol/dichloromethane was treated with triethylamine, methanolic HCl and sodium cyanoborohydride to afford the desired product. MS (ES+) 666 ([MH]⁺X 490 ([M-ArS0₂-]⁺X

Example 13Q: l-[4-(4-Chloro-benzenesulfonyl)-4-(2,5-difluoro phenyl)- cyclohexyl]-3-methanesulfonyl-propan-2-one

Dimethyl sulfone was reacted with 1 equivalent of lithium dusopropylamide in tetrahydrofuran at -78°C, and the resulting carbanion was reacted in situ with Intermediate B at -78°C for 30 minutes then at ambient temperature for 1 hour to yield the desired product. MS (ES+) 505 ([MH]⁺X Example 131: l-[4-(4-Chloro-benzenesulfonyl)-4-(2.5-difluoro-phenyl)- cyclohexyl]-3-methanesulfonyl-3-methyl-butan-2-one

Prepared from Example 131 by alkylation with excess Mel in 1,2- dimethoxye thane at room temperature using sodium hydride as base. ( MS (ES+) 555 (DVINa]⁺).

Example 132: l-[4-(4-Chloro-benzenesulfonyl)-4-(2,5-difluoro-phenyl)- cyclohexyl]-3-methanesulfonyl-butan-2-one

The product from Example 130 was methylated as described in Example 131, using one equivalent each of Mel and NaH. MS (ES+) 541 ([MNa]⁺X

Example 133: 2-[4-(4-Chloro-benzenesulfonyl)-4-(2,5-difluoro-phenyl)- cvclohexyl]-l-(l,l-dioxo-tetrahvdrothiophen-2-yl)-ethanone

Prepared by the procedure of Example 130 using tetramethyl sulfone. MS (ES+) 553 ([MNa]⁺X

Examples 134-146

The following were prepared by reaction of Intermediate H with ArLi in diethyl ether or THF at -78°C:

(a) - oxidation as final step (urea hydrogen peroxide, trifluoroacetic anhydride in dichloromethane).

(b) - via oxidation of the corresponding hydroxymethyl compound (Dess- Martin periodinane in dichloromethane).

(c) — via oxidation of the corresponding aldehyde (sulfamic acid and sodium chlorite in dichloromethane/wate ).

(d) — via condensation of the corresponding aldehyde with (EtO)₂POCH₂C0₂Et.

(e) — via hydrogenation of the corresponding olefin (over Rh/C catalyst).

(f) - via hydrolysis of the corresponding ester (LiOH in aqueous THF).

(g) — via reaction of the corresponding aldehyde with morpholine and sodium cyanoborohydride in MeOH/HCl.

Example 152-155.157.161.162

The following were prepared from Intermediate J by reaction with the appropriate acid chloride or anhydride and triethylamine in dichloromethane under nitrogen at ambient or reduced temperature (method A) or by couphng with the appropriate carboxyhc acid in the presence of l-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, hydroxybenzotriazole and triethylamine in DMF at ambient temperature (method B), or by refluxing in dioxan with sulfamide (method C).

Example 156. 158-160

The following were prepared from Intermediate J by reaction with catechol sulphate in dry tetrahydrofuran under nitrogen at 0°C, and treatment of the resulting 2-hydroxyphenyl sulfamate with the appropriate amine R₂NH at 80°C in dioxan.

(a) — by hydrolysis of Example 159

Examples 163 -165

The following were prepared from Intermediate C by reaction with triethylamine and diphenylphosphoryl azide in toluene at 110°C for 3 hours, followed by treatment with the appropriate amine R₂NH for a further 18 hours at ambient temperature. MS (ES+)

Example 167: [4-(4-Chloro-benzenesulfonyl)-4-(2,5-difluoro-phenyl)- cyclohexyl] -sulfamic amide

Intermediate R (100 mg, 0.26 mmol in dioxane (4 ml) was treated with sulfamide (125 mg, 1.30 mmol) and heated to reflux for 1 hour, then cooled to room temperature, diluted with ethyl acetate, washed with H2O, dried (MgS0₄) and evaporated. Trituration of the residue in ether afforded the desired product (50 mg, 42% yield), m/z = 465, 467 [MH]⁺

Examples 168-184:

The following were prepared from Intermediate R by treatment with the appropriate sulfamoyl chloride and triethylamine in a mixture of dichloromethane and dimethylacetamide (3^"-l) (Method A); or by treatment with the appropriate sulfamoyl chloride and Hύnig's base in acetonitrile at 80°C (Method B) The relevant sulfamoyl chlorides were prepared by published methods (DE 3429048; FR 2739858; J.Org.Chem., 41, 4029-9, 1976; J.Heterocyclic Chem.,2000, 773) or adaptations thereof.

(a) - treatment of corresponding pivalate with DIBAL-H in toluene at ambient temp.

(b) - oxidation of corresponding alcohol with Dess-Martin periodinane I dichloromethane at ambient temperature. (c) - reaction of corresponding ketone with MeMgBr in THF at 0°C. (d) — reaction of Ex. 182 with Me₂NH and sodium cyanoborohydride in MeOH at ambient temperature.

Example 185: Pyrrolidine-1-sulfonic acid [4-(2,5-difluoro-phenyl)-4-(4- trifluoromethyl-benzenesulfonyl)-cyclohexyl]-amide

Sulfuryl chloride (236 μl, 2.9 mmol) in toluene (2 ml) was cooled to -30°C and pyrrohdine (242 μl, 29 mmol) added dropwise over 10 min. The reaction was stirred for 1.5 h at — 30°C, diluted with toluene, washed with water, aqueous HCl (2 M) and brine, dried (MgS0₄), filtered and evaporated to give an oil. This was dissolved in dichloromethane (l ml) and added to a solution of Intermediate S (120 mg, 0.29 mmol) in dichloromethane (2 ml) at 0°C and the reaction aUowed to warm to room temperature and stirred for 18 h. The mixture was diluted with dichloromethane, washed with water, brine, dried (MgSθ4) filtered and evaporated. The residue was purified by flash chromatography eluting with isσ-hexane/ethyl acetate (1:1) to give a white sohd (62 mg). MS [MH⁺] 553 Example 186: Pyrrolidine-1-sulfonic acid [4-(2,5-difluoro-phenyl)-4-(6- trifluoromethyl- yridyl- 3-sulfonyl) -cyclohexyl] -amide

Prepared by the procedure described for Example 185, using Intermediate T. m/z = 554 (MH+)

Claims

CLAIMS:

1. A compound of formula I:

I wherein

X represents SCN, SR¹, S(0)R¹, (CR^aR^b)_mS0₂R¹, S0₂N(R²)₂, S02NHCOR¹, S0₂NHN(R²)₂₎ OS0₂N(R²)₂, OS(0)N(R²)₂, OSO2NHCOR¹, COR⁴, NHCOR¹, NHC02R¹, NHCON(R²)₂, NHSO2R¹ or NHS0 N(R²)₂; m is 0 or 1 R^a represents H or Cι-4alkyl;

R^b represents H, Cι-₄alkyl, C0₂H, Cι-₄alkoxycarbonyl or Ci- 4alkylsulphonyl; or R^b may combine with R¹ to form a 5- or 6-membered ring;

L represents a bond, =CH or -(CHR^a)_n-; with the proviso that L does not represent a bond when X represents NHCOR¹, NHCO2R¹ or

NHSO2R¹; and with the proviso that if L represents =CH-, X represents

n is 1, 2 or 3;

R¹ represents CF3 or Ci-εalkyl, C2-6alkenyl, C3-9cycloalkyl or C3-6cycloalkylCι-6alkyl, any of which may bear up to 2 substituents selected from halogen, CN, CF₃, OR³, COR³, CO2R³, OCOR^3a, S0₂R^3a, N(R⁵)₂, and CON(R⁵)₂, or R¹ represents aryl, arylCi-ealkyl, C-heterocyclyl or C-heterocyclylC i-βalkyl; or R¹ may combine with R^b to form a 5- or 6-membered ring; each R² independently represents H, Ci-βalkoxy, or Ci-ealkyl, C₂- βalkenyl, C3-9cycloalkyl or C3-6cycloalkylCι-Galkyl, any of which may bear up to 2 substituents selected from halogen, CN, CF₃₎ OR³, COR³, C0₂R³, OCOR^3a, and CON(R⁵)₂; or aryl, arylC_{1 G}alkyl, C-heterocyclyl or C-heterocyclylCi-ealkyl; or two R² groups together with a nitrogen atom to which they are mutually attached complete an N-heterocyclyl group;

R³ represents H, Cι-₄alkyl, phenyl or heteroaryl;

R^3a represents C₁-4alkyl, phenyl or heteroaryl;

R⁴ represents (CR^aR^b)S02R¹, pyridine N-oxide, or phenyl or heteroaryl which bear a substituent selected from CO2H, methylenedioxy, difluoromethylenedioxy, COR³, C-heterocyclyl, Cι-4alkylsulphonyl and substituted Ci-ealkyl, Ci-ealkoxy, C₂-6alkenyl or C₂-6alkenyloxy wherein the substituent is selected from halogen, CN, CF₃, OR³, C0₂R³, OCOR^3a, N(R⁵)₂ and CON(R⁵)₂;

R⁵ represents H or Cι-₄alkyl, or two R⁵ groups together with a nitrogen atom to which they are mutually attached complete an azetidine, pyrrohdine, piperidine, morpholine, thiomorpholine or thiomorpholine -1,1- dioxide ring;

Ar¹ and Ar² independently represent phenyl or heteroaryl, either of which bears 0-3 substituents independently selected from halogen, CN, N0₂₎ CF3, CHF₂, OH, OCF₃, CHO, CH=NOH, Cι-₄alkoxy,

Cι-4alkoxycarbonyl, C₂-6acyl, C₂-6alkenyl and Cι-4alkyl which optionally bears a substituent selected from halogen, CN, N0₂, CF3, OH and Ci-4alkoxy;

"aryl" at every occurrence thereof refers to phenyl or heteroaryl which optionally bear up to 3 substituents selected from halogen, CN, N0₂, CFs, OCF3, OR³, COR³, C0₂R³, OCOR^3a, N(R⁵)₂, CON(R⁵)₂ and optionally-substituted Ci-ealkyl, Ci-ealkoxy, C2-6alkenyl or C₂-6alkenyloxy wherein the substituent is selected from halogen, CN, CF3, phenyl, OR³, CO2R³, OCOR^3a, N(R⁵)₂ and CON(R⁵)₂; and "C-heterocyclyl" and "N-heterocyclyl" at every occurrence thereof refer respectively to a heterocychc ring system bonded through carbon or nitrogen, said ring system being non-aromatic and comprising up to 10 atoms, at least one of which is O, N or S, and optionally bearing up to 3 substituents selected from oxo, halogen, CN, N0 , CF₃, OCF₃, OR³, COR³, CO2R³, OCOR^3a, OS0₂R^3a, N(R⁵)₂, CON(R⁵)₂ and optionally -substituted phenyl, Ci-ealkyl, Ci-ealkoxy, C₂-ealkenyl or C₂-6alkenyloxy wherein the substituent is selected from halogen, CN, CF₃, OR³, C0₂R³, OCOR^3a, N(R⁵)₂ and CON(R*)₂; or a pharmaceutically acceptable salt thereof.

2. A compound according to claim 1 wherein X is selected from SR¹, (CR^{a b} SOaR¹, S0₂N(R²)₂₎ OS0₂N(R²)₂, COR⁴, NHCOR¹, NHCO2R¹, NHCON(R )₂, NHSO2R¹ and NHS0₂N(R )₂.

3. A compound according to claim 1 which is in accordance with formula IP

II or a pharmaceutically acceptable salt thereof.

4. A compound according to claim 1 which is in accordance with formula IP

III wherein p is 0, 1, 2 or 3; Y is SCN, SR¹, S(0)R¹, (CR^aR^b)_mS0₂R¹ ₎ S0₂N(R )₂, SO2NHCOR¹, S0 NHN(R²)₂, OS0₂N(R²)₂₎ OS(0)N(R²)₂₎ OSO2NHCOR¹, COR⁴, NHCON(R²)₂ or NHS0₂N(R²)₂; and m, R^a, R^b, R¹, R², R⁴, Ar¹ and Ar² are as defined in claim l; or a pharmaceutically acceptable salt thereof.

5. A compound according to claim 1 which is in accordance with formula IV:

IV wherein Z represents SO2R¹ or COR⁴; and R¹, R⁴, Ar¹ and Ar² are as defined in claim l; or a pharmaceutically acceptable salt thereof.

6. A compound according to any previous claim wherein Ar¹ is 4- chlorophenyl or 4-trifluoromethylphenyl or 6-(trifluoromethyl)-3-pyridyl and Ar² is 2,5-difluorophenyl.

7. A pharmaceutical composition comprising a compound according to any previous claim and a pharmaceutically acceptable carrier.

8. A compound according to any of claims 1-6 for use in a method of treatment of the human body.

9. The use of a compound according to any of claims 1-6 in the manufacture of a medicament for treating or preventing Alzheimer's disease.

10. A method of treatment of a subject suffering from or prone to a condition associated with the deposition of β-amyloid which comprises administering to that subject an effective amount of a compound according to any of claims 1-6.