NO148779B - BIS-PYRIDINIUM ALKANES SUITABLE FOR USE AS DISINFECTIVES AND TO COMBAT TOOTH PLAQUE - Google Patents

Abstract

Bis-pyridinium alkanes suitable for use as disinfectants and for the control of dental plaque.

Description

The present invention relates to bis-pyridinium alkanes suitable for use as disinfectants and for combating dental plaque.

US patent 3,055,902 describes a group of bis-(4-amino-1-pyridinium)alkanes as intermediates for the production of the corresponding bis-(4-amino-1-piperidino)alkanes which are indicated to have bacteriostatic and bactericidal effects.

W.C. Austin et al., J.Pharm. Pharmacol. 11, 80-93

(1959) describe 1,10-bis-(4-amino-1-pyridinium)decane iodide

and 1,10-bis-(4-acetamido-1-pyridinium)decanediiodide. It is indicated that certain compounds in the large and highly varying group of quaternary ammonium compounds indicated in the said patent have activity against amoebae, bacteria and parasitic worms, but no biological data is given for any of the above compounds.

According to the present invention, bis-pyridinium alkanes suitable for use as disinfectants and for combating dental plaque are provided, and these compounds are characterized by having the general formula:

where R is an alkyl group of from 3 to 12 carbon atoms, cyclohexyl or p-chlorophenyl, Y is a straight-chain alkylene group of from 4 to 14 carbon atoms, or a p-xylene group, and A is an anion; provided that when R is p-chlorophenyl, Y is a straight chain alkylene group of from 6 to 14 carbon atoms, and when R is unsubstituted cyclohexyl, then Y is an alkylene group of from 8 to 14 carbon atoms.

The present compounds are used in oral hygiene as they can be used in preparations to prevent the formation of dental plaque, where the preparation includes an effective amount of one of the compounds in question as well as a compatible and acceptable carrier. The compounds can further be used in preparations for combating bacteria, fungi and viruses, and are suitable for topical application, and include an effective amount of a compound according to the present invention as well as an acceptable carrier. A skin cleansing preparation consists of an antibacterial, antifungal and antiviral effective amount of a compound of formula I as well as a compatible acceptable surfactant and a compatible acceptable carrier or diluent. A preparation containing a compound according to the present invention for combating bacteria, fungi and viruses can be used for application to dead surfaces and includes an effective amount of the compound in mixture with a suitable diluent.

Compounds of formula I can be prepared by reacting a 4-(R-amino)pyridine of the formula: where R has the above meaning, with a disubstituted alkane of the formula:

where Y has the above meaning and separates the Z groups with 4-14 carbon atoms, and where Z is chlorine, bromine, iodine, methanesulfonyloxy, ethanesulfonyloxy, benzenesulfonyloxy or p-toluenesulfonyloxy.

The reaction to prepare compounds of formula I may conveniently be carried out by reacting two moles of a 4-(R-amino)pyridine (formula III) with 1 mole of an appropriate disubstituted alkane (formula IV) in an inert solvent such as a lower- alkanol, acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, benzene, toluene, xylene and the like, at temperatures of 80-150°C for periods of 1 to 24 hours. Typically, the reactants will be heated from 60 to 100°C in acetonitrile or N,N-dimethylformamide or a mixture of these solvents or in a lower alkanol for a period of 2 to 20 hours.

Alternatively, the reaction can be carried out in the absence of a solvent by heating stoichiometric amounts of the reactants at temperatures of 120-150°C for from 2 to 5 hours.

The resulting bis-[4-(R-amino)-1-pyridinium compounds (formula I) can be isolated in the usual way, e.g. by filtration, if the product is insoluble in the reaction medium, or by diluting the reaction mixture with a non-polar solvent such as ether, benzene or hexane to thereby precipitate the product, or by evaporating the reaction medium so that the product is obtained as a residue. The resulting crude product can be purified by crystallization from a suitable solvent in the presence of an absorbent, e.g. charcoal or diatomaceous earth.

The bis-[4-(R-amino)-1-pyridinium 7~ compound prepared as indicated above will of course contain an anion (A in formula I) which corresponds to the leaving group in the disubstituted alkane (Z in formula IV).

However, the anion group can be varied if desired, in the usual way, e.g. by passing a solution of a pyridinium compound in a suitable solvent such as methanol, ethanol or water, through a layer of synthetic ion exchange resin containing the desired anion. The solvent can then be evaporated, and the resulting pyridinium compound containing the desired anion can then be purified by recrystallization from a suitable solvent.

Alternatively, a pyridinium compound can be reacted with a soluble salt containing the desired anion in connection with a counter cation which combines with the anion in the pyridinium compound so that an insoluble precipitate is produced. This can then be separated out, obtaining a solution of the pyridinium compound containing the desired anion. For example, a bis-[4-(R-amino)-1-pyridinium]-alkane dihalide can be reacted with the silver salt of an organic or inorganic acid. The precipitated silver halide is removed, whereby a solution of the pyridinium compound containing the desired organic or inorganic anion is obtained.

The above type of exchange reactions can also be used to prepare insoluble pyridinium compounds. Thus, a soluble bis-/4-(R-amino)-1-pyridinium/- compound can be reacted with a soluble salt containing the desired anion which combines with the pyridinium cation, thereby obtaining the desired product as an insoluble precipitate. Such insoluble pyridinium salts can be suitable for good isolation and purification, and can be suitably processed into emulsions, creams, pastes, ointments or powders, and can also be used as depot preparations to provide a slow and delayed release of the pyridinium compound . Furthermore, such insoluble salts discharged by certain anions, e.g. of the type described in US patent 3,937,807 be effective in reducing the staining of teeth and in preventing the development of dental plaque.

Thus, should the anion part of a given compound have certain undesirable properties such as solubility, stability, molecular weight, physical appearance, toxicity or the like, then this compound can easily be converted into another and more suitable form. For use on skin and other tissues or in the oral cavity, one will of course use pharmaceutically acceptable anions such as fluoride, chloride, bromide, iodide, methanesulfonate and the like.

The 4-(R-amino)pyridines (formula III) used as starting compounds are generally known, and if they are particularly new, they can be prepared by the methods indicated for the preparation of the known compounds.

Conveniently, said 4-(R-amino)pyridines can be prepared by reacting 4-chloro- or 4-bromopyridine or N-(4-pyridyl)-pyridinium chloride hydrochloride with a suitable substituted amine. The reaction is usually carried out by heating the reactants in the absence of a solvent at 150-225°C for periods of 1.5-3 hours. The product can be insulated in the usual way, e.g. by extraction from an alkaline aqueous medium into an organic solvent such as ether, methylene chloride or chloroform, after which the organic solvent is evaporated

agent and crystallizes the residue from a suitable solvent.

Alternatively, 4-(R-amino)pyridines obtained by catalytic hydrogenation of a mixture containing 4-aminopyridine and a carbonyl compound containing a suitable carbon content. The reaction is usually carried out at temperatures from 50-70°C in a suitable solvent, e.g. ethanol, , under a hydrogen pressure of 1.5-4.5 kg/cm 2 in the presence of a palladium hydrogenation catalyst. Usually a hydrogenation time of 4-10 hours will be satisfactory. The use of a large excess of the carbonyl compound, e.g. 200% or greater will advantageously give a higher yield of a pure product in a reaction time of 5 hours or less. After the catalyst has been removed, the product can be isolated by evaporating the solvent and either distilling the residue or recrystallizing it from a suitable solvent.

The reaction between an aldehyde with a suitable carbon-

content with 4-aminopyridine in the presence of formic acid at elevated temperature also gives 4-(R-amino)pyridines.

4-(R-amino)pyridines can also be prepared by

acylate 4-aminopyridine with an acyl halide of appropriate carbon content and then reduce the resulting amide. The acylation is carried out in a commonly known manner, e.g. to react 4-aminopyridine with an acyl halide in an inert soln.

agent such as methylene dichloride or chloroform in the presence of an acid acceptor, e.g. triethylamine. The produced amide is then reduced with a complex metal hydride, e.g.

lithium hydride in a suitable solvent such as e.g. tetrahydrofuran, ether or dioxane, and the amine product can be iso-

is read in a commonly known manner.

Disubstituted alkanes of formula IV can also be used

as starting materials, and such compounds are usually known, or if they are not, they can be prepared by

methods known to prepare the known compounds.

As is described in detail below, compounds of formula I will have in vitro antimicrobial activity against several types of microorganisms of the type that include both gram positive and gram negative bacteria, further against many types of fungi and Herpes virus. The compounds can thus be used as antimicrobial or antiseptic agents that can be applied topically to clean human skin or other tissue as well as to disinfect dead surfaces. Thus, the compounds can be used in topical antiseptic solutions for the treatment of wounds, as antibacterial cleansers for example for surgical purposes, for the treatment of skin before operations, in soaps and creams or in ordinary household cleaners, disinfectants and protective coatings of the type such as paints, varnishes and wax. The compounds can be used as such or can be combined with common diluents or carriers, compatible cationic, anionic or non-ionic surfactants, buffering agents, perfumes or dyes, and can be applied to the surface to be disinfected in the usual way, e.g. by scrubbing, immersion, spraying, rubbing or the like.

For use as skin cleansing agents, said bis-[4-(R-amino)-1-pyridinium/compounds can be prepared as liquids, or the liquid can be thickened with certain additives into a gel or paste or molded into a piece in a well-known manner. For example, the compound may be formulated with any compatible pharmaceutically acceptable surfactant, preferably a nonionic surfactant such as the polyoxyethylene-polyoxypropylene copolymer of the type described in US Patent 3,855,140, amine oxides such as the stearyldimethylamine oxide which is described in US patent 3,296,145 and the like or with mixtures of such substances. Furthermore, the preparations may contain pharmaceutical acceptable diluents such as water, lower alkanols and the like, acids, bases or buffers so that a pH of between 5.0 and 7.5 is obtained, and possibly perfumes and dyes. Said bis-[4-(R-amino)-1-pyridinium/compounds are usually present in such preparations or compositions in a concentration of 0.5-2.0% by weight, preferably approx. 1.0% by weight.

When the compounds are worked up in a tincture then can

this is combined with water, a lower-alkanone, e.g. acetone,

and a lower alkanol such as ethanol. If desired, the tincture can be colored with a coloring agent. The active stock-

part is usually present in a concentration of 0.05-1.0%

(v/v), preferably 0.1% (v/v).

Alternatively, the compounds can be worked up in suitable pharmaceutical diluents to treat infections caused by bacteria, fungi or Herpes virus, e.g. in the form of ointments or creams or the like by being processed into common base substances for such preparations, e.g. alkyl polyether alcohols, cetyl alcohol, stearyl alcohol and the like, or as powders by adding common powder substances such as starch, talc and the like, or gel preparations

rates by adding common gel substances such as glycerol and tragacanth. They can also be processed for use in aerosols or in foaming agents.

When using the compounds to disinfect dead surfaces, the compounds can be worked up with known detergents such as trisodium phosphate, borax and the like,

said pyridinium compounds are usually present in such preparations in a concentration of up to 10% by weight.

Which is described in detail in the following can

certain compounds of formula I are used to prevent the formation of

late of dental plaque. When the compounds are to be used for this purpose, they can conveniently be applied to the teeth in the form of a mouthwash, a toothpaste or a dental chalk. The compounds can be prepared with common ingredients of the type used in such preparations, e.g. water, alcohol, glycerin, buffers, thickeners, flavoring agents and coloring agents. Such preparations may optionally contain other known ingredients of the type that are effective in reducing the staining of teeth,

, e.g. such agents as are described in US patent 3,934,002, e.g. zinc phenol sulfonate, 8-hydroxyquinoline, disodium ethane-1-hydroxy-1,1-diphosphonate etc., as well as aminocarboxylate compounds of the type specified in US patent 3,937,807, e.g. nitrilotriacetic acid, 2-hydroxyethylnitriloacetic acid or water-soluble salts thereof. Generally, said bis-[4-(R-amino)-1-pyridinium/alkanes will be used in such preparations in concentrations of 0.005-0.05% by weight, preferably approx. 0.01% by weight.

It is further understood that the diluents, carriers and additives found in the aforementioned preparations are compatible with the active ingredient, i.e. the effectiveness against bacteria, fungi and viruses found in the described bis-/4-(T-amino) -1-pyridinium/compounds.

The molecular structure of the present compounds was established on the basis of studies of their infrared and nuclear magnetic spectra, and confirmed by an agreement between calculated and found values for the elements present.

The following examples illustrate the invention.

Example_el_2

A. A mixture containing 130 g (0.67 mol). 4-bromopyridine hydrochloride and 152 g (1.0 mol) of n-heptylamine hydrochloride were heated in an oil bath. When the bath temperature reached 180-185°C, the reaction mixture began to melt, and stirring began. At 190-195°C the melting was complete, and the liquid mixture was stirred at 210-220°C for 2.5 hours. It was then cooled to room temperature, and the resulting solid was dissolved in water, made alkaline with 35% aqueous sodium hydroxide, and the product was extracted with chloroform. The chloroform extracts were dried over anhydrous sodium sulfate and evaporated to dryness under reduced pressure. The resulting viscous oil was diluted with a small amount of n-hexane and cooled to give a solid which was collected by filtration and dried to give 86.6 g of 4-(heptylamino)-

pyridine, m.p. 4 9-51°C.

B. Alternatively, 4-(heptylamino)pyridine can be prepared as follows: A mixture containing 229 g (1.0 mol) of N-(4-pyridyl)pyridinium chloride hydrochloride and 228 g (1.5 mol) of n-heptylamine hydrochloride was heated for 2 hours in an oil bath at 215°C. The reaction mixture was cooled to 80°C, diluted with ice water, made alkaline with 35% aqueous sodium hydroxide and extracted successively with ether and chloroform. The organic extracts were combined and evaporated to dryness under reduced pressure. The resulting viscous oil was dissolved in ether, and the ether solution was washed with water. The aqueous wash was back-extracted with chloroform, and the chloroform extract was combined with the ether solution. The combined organic solutions were dried over anhydrous sodium sulfate and evaporated to dryness under reduced pressure. By cooling the remaining oil to -78°C, a partial solidification was obtained. The semi-solid was diluted with a small amount of ether and filtered. This resulted in a solid which was dissolved in a mixture of acetonitrile and chloroform,

and the resulting solution was treated with decolorizing carbon, filtered, and the filtrate evaporated to dryness under reduced pressure. The resulting semi-solid was diluted with a small amount of ether and cooled. A solid was thus obtained which was collected by filtration and washed with a small volume of cold ether, and after drying, 84.6 g of 4-(heptylamino)pyridine, m.p. 50-52°C.

C. 4-(heptylamino)pyridine was also prepared by hydrogenating a mixture containing 4-aminopyridine and heptaldehyde as described in example 1 B below. D. A stirred hot solution containing 10.0 g (0.052 mol) 4-(heptylamino)pyridine in 40 mL acetonitrile was added dropwise to a solution containing 9.3 g (0.026 mol) 1,14-dibromotetradecane in 230 mL acetonitrile, and the mixture was then refluxed for 20 hours. The product that precipitated upon cooling the reaction mixture to room temperature, was collected by filtration, washed with cold acetonitrile and dried, whereby 13.9 g of 1,14-bis-(4-(heptylamino)-1-pyridinium/tetradecanedibromide, m.p. 88-90°C.

Example_el_2

A solution containing 5.0 g of 1,14-/4-(heptyl-amino)-1-pyridinium/tetradecanedibromide in 5.0 ml of methanol was added to the top of a column with a diameter of 7.5 cm and containing 500 ml synthetic anion exchange resin in the chloride form ("Amberlite IRA 400"), packed in methanol and then eluted with four 125 ml portions of methanol. The combined eluate was evaporated to dryness under reduced pressure, and the remaining oil was dissolved in ethanol, treated with decolorizing carbon and evaporated to dryness. The resulting solid was treated with ether containing a few drops of acetonitrile, collected by filtration and dried over phosphorus pentoxide under vacuum to give 3.94 g of 1,14-bis-(4-(heptylamino)-1-pyridinium)tetradecanedichloride, m.p. 113-116°C.

Example_el_3

A stirred suspension containing 11.54 g (0.06 mol) of 4-(heptylamino)pyridine in 75 ml of acetonitrile was refluxed until a clear and homogeneous solution was obtained. The clear solution was then added dropwise to a hot solution containing 9.84 g (0.03 mol) of 1,12-dibromododecane in 75 ml of acetonitrile. After the addition was finished, refluxing was continued for 18 hours. After cooling to room temperature, the reaction mixture was evaporated to dryness under reduced pressure. The remaining solid was stirred in ether, collected by filtration and dried for 48 hours in vacuum at 60°C, and 21.1 g of 1,12-bis-[4-(heptyl-amino)-1-pyridinium] was obtained. dodecane dibromide, m.p. 101-103°C.

Example<_>el<_>4

A. A solution containing 6.6 g of 1,12-bis-(4-(heptyl-amino)-1-pyridinium-7dodecanedibromide in 25 ml of methanol was added to the top of a 7.5 cm diameter column packed with 1 liter synthetic anion exchange resin in the chloride form ("Amberlite IRA 400") in methanol and slowly eluted with 100 mL portions of methanol until 700 mL of eluate was collected. The combined eluate was evaporated to dryness under reduced pressure below 25°C. The resulting gum was treated several times with a 6 to 1 mixture of ether and acetonitrile and then dried under vacuum to give 5.0 g of 1,-12-bis-(4-(heptylamino)-1-pyridinium/dodecane dichloride , m.p. 109-112°C.

B. Alternatively, a mixture containing 76.8 g (0.4 mol) 4-(heptylamino)pyridine and 47.8 g (0.2 mol) 1,12-dichlorododecane can be heated for 4 hours at 125-130°C . After slight cooling, 300 ml of acetonitrile was added, and the resulting mixture was heated on a steam bath to obtain a complete solution and then stored in a refrigerator overnight. The precipitated product was collected by filtration, washed with cold acetonitrile and ether and the hygroscopic product was immediately dried under vacuum, whereby 112 g of 1,12-bis-(4-(heptylamino)-1-pyridinium 7dodecanedichloride, m.p. 112-115°C.

Example_el_5

A. A mixture containing 100 g (0.51 mol) of 4-bromopyridine hydrochloride and 110 g (0.8 mol) of n-hexylamine hydrochloride was heated on an oil bath. When the bath temperature reached 175-180°C, the reaction mixture began to melt and stirring was begun.

The temperature was then raised to 227°C and stirring continued for 3.5 hours. After cooling to room temperature, the mixture was dissolved in hot water, the resulting solution cooled

with ice, made alkaline with dilute aqueous sodium hydroxide and extracted with chloroform. The chloroform extracts were dried

over anhydrous sodium sulfate and evaporated to dryness under reduced pressure. The residue was treated with ether and cooled. The resulting solid was collected by filtration and washed with cold ether. Evaporation of the filtrate gave another yield of solid. The solids were combined, dissolved in chloroform, treated with decolorizing carbon and filtered. The filtrate was evaporated under reduced pressure and the residue was treated with cold ether. The product thus obtained was collected by filtration, washed with cold ether and dried, thereby obtaining 63.6 g of 4-(hexylamino)-pyridine, m.p. 66-68°C. Evaporation of the filtrate gave a further 7.0 g with a m.p. at 65-67°C.

B. Alternatively, 4-(hexylamino)pyridine can be prepared

in the following manner: A mixture containing 229 g (1 mol) of N-(4-pyridyl)pyridinium chloride hydrochloride and 207 g (1.5 mol) of n-hexylamine hydrochloride was stirred and kept heated for 1.75 hours at 175-185°C. The reaction mixture was cooled and diluted with 750 ml of ice water. The resulting solution was made alkaline with 35% aqueous sodium hydrochloride and after dilution with 1 liter of water was extracted with ether and then with dichloromethane. The organic extracts were combined, dried over anhydrous sodium sulfate and evaporated to dryness under reduced pressure. The residue was crystallized from ether, redissolved in chloroform, and the solution treated with decolorizing carbon and filtered. The filtrate was evaporated to dryness under reduced pressure and the residue treated with a mixture of ether and acetonitrile. The solid was redissolved in chloroform and the resulting solution treated with decolorizing carbon and filtered. The filtrate was evaporated to dryness under reduced pressure, and the residue was treated with cold ether to give 71.0 g of 4-(hexylamino)pyridine, m.p. 68-70°C.

C. A stirred hot solution containing 10.7 g (0.06 mol) 4-(hexylamino)pyridine in 50 ml acetonitrile was added dropwise to a solution containing 10.7 g (0.03 mol) 1,14-dibromotetradecane in 250 ml of acetonitrile, and the resulting mixture was refluxed for 22 hours. The reaction mixture was then evaporated to dryness under reduced pressure. The remaining solids were dissolved in acetonitrile, and the resulting solution treated with decolorizing carbon and filtered. The filtrate was evaporated to dryness under reduced pressure and the resulting oil crystallized from acetonitrile. The product was collected by filtration and dried for 48 hours at 70°C/0.1 mm Hg to give 13.4

g 1,14-bis-(4-(hexylamino)-1-pyridinium 7-tetradecanedibromide, m.p. 91-93°C.

Example_el_6

By using the same method as described in example 2, but by using 5.0 g of 1,14-bis-/4-(hexylamino)-1-pyridinium/tetradecanedibromide, 4.33 g of the corresponding dichloride was produced, m.p. 94-95°C.

Example_el_7

Using the same procedure as described in Example 5 C, but using 10.7 g (0.06 mol) of 4-(hexylamino)pyridine and 9.85 g (0.03 mol) of 1,12-dibromododecane , 17.6 g of 1,12-bis-[4-(hexylamino)-1-pyridinium]-dodecane dibromide were produced, m.p. 122-124°C.

Example_el_8

By using the same procedure as described in example 2, but by using 5.0 g of 1,12-bis-/4-(hexylamino)-1-pyridinium/dodecanedibromide, 3.69 g of the corresponding dichloride was produced, m.p. . 86-88°C.

<Example>_<9>

A. A mixture containing 183.3 g (0.8 mol) of N-(4-pyridyl)pyridinium chloride hydrochloride and 162 g (0.98 mol) of n-octylamine hydrochloride was heated in an oil bath at 225-230°C (internal temperature of 188°C), and the resulting liquid was stirred at this temperature for 2.5 hours. The reaction mixture was then cooled to 70°C, diluted with 1 liter of ice and water, made alkaline with 30% aqueous sodium hydroxide and extracted with chloroform. The chloroform extracts were dried over anhydrous sodium sulfate, treated with decolorizing carbon and evaporated to dryness under vacuum. The resulting oil was cooled to -78°C. The semi-solids that formed were treated with ether, and the solid was collected by filtration, washed with cold ether and dried. The filtrate gave another yield of 10 g. The combined yields were combined, dissolved in chloroform and then treated with decolorizing carbon and filtered (repeated 3 times), after which the chloroform solution was evaporated to dryness under reduced pressure. The resulting solid was treated with ether, cooled, collected by filtration and washed with cold ether-hexane to give 63.3 g of almost colorless 4-(octylamino)pyridine, m.p. 62-63°C. B. Alternatively, 4-(octylamino)pyridine can be prepared as follows: A mixture containing 94 g (1 mol) 4-aminopyridine, 384 g (3 mol) octaaldehyde, 7 g 10% palladium-on-carbon hydrogenation catalyst and sufficient absolute ethanol to give a total volume of 1.2 litres, was hydrogenated for 4.5 hours at 70-90°C under an internal hydrogen pressure of approx. 3.3 kg/cm 2 . After cooling, the catalyst was removed by filtration, and the filtrate was evaporated to dryness under reduced pressure. The remaining oil was crystallized on standing, and the solid product was treated with hexane, collected by filtration, washed with fresh hexane and dried at 40°C under vacuum, whereby 182 g of 4-(octylamino)pyridine, m.p. 70-73°C.

C. A stirred hot solution containing 10.0 g (0.49 mol) 4-(octylamino)pyridine in 150 mL acetonitrile was added dropwise to a solution containing 7.4 g (0.0245 mol) 1,10-dibromodecane in 50 ml of acetonitrile, and the resulting mixture was refluxed for 18 hours. After cooling and stirring for 1 hour at room temperature, the precipitated solid was collected by filtration, washed with acetonitrile and dried for 48 hours at 85°C, and 15.6 g of 1,10-bis-/4-( octyl-amino)-1-pyridinium/decanedibromide, m.p. 163-164°C.

Example_el_1_0

A. By using the same method as described in example 2, but by using 5.0 g of 1,10-bis-[4-(octylamino)-1-pyridinium 7 decanedibromide, 4.31 g of the corresponding dichloride was produced, m.p. 213-214°C.

B. Alternatively, a mixture containing 61.8 g of 4-(octylamino)pyridine and 31.5 g of 1,10-dichlorodecane can be stirred and heated slowly at 120°C. The heat source was removed and the temperature of the now exothermic reaction continued to rise to 180°C. As soon as the reaction mixture began to crystallize, 250 ml of N,N-dimethylformamide was quickly added and the resulting mixture was heated to obtain a clear homogeneous solution which was then cooled to 0°C. The precipitated product was collected by filtration, washed with ether and dried for 24 hours under vacuum at 60°C, thereby obtaining 73 g of 1,10-bis-(4-(octylamino)-1-pyridinium 7 decanedichloride, m.p. 215-217°C.

Eczema gel_1_l

Using the same procedure as described in Example 9 C, but using 11.1 g (0.054 mol) 4-(octyl-amino)-pyridine and 7.34 g (0.027 mol) 1,8-dibromooctane and heating the mixture for 6 hours under reflux, 15.6 g of 1,8-bis-[4-(octylamino)-1-pyridinium 7-octane dibromide were obtained, m.p. 174-175°C.

Example_el_1_2

By using the same procedure as described in example 2, but by using 5.0 g of 1,8-bis-[4-(octylamino)-1-pyridinium 7-octane dibromide, 4.30 g of the corresponding dichloride was obtained, m.p. 210-211°C.

Example_el_1_3

Using the same procedure as described in Example 9 C, but using 11.1 g (0.054 mol) of 4-(octyl-amino)pyridine and 6.6 g (0.027 mol) of 1,6-dibromohexane and heating and boiling the mixture under reflux for 9 hours, 15.1 g of 1,6-bis-[4-(octylamino)-1-pyridinium/-hexanedibromide were produced, m.p. 136-138°C.

Example_el_1.4

The same procedure as described in example 2 was used, but 5.0 g of 1,6-bis/4-(octylamino)-1-pyridinium-7-hexane dibromide was used and 4.23 g of the corresponding dichloride was produced, m.p. 189-191°C.

Example_el_1_5

A stirred hot solution containing 2.06 g (0.01 mol) 4-(octylamino)pyridine in 15 ml acetonitrile was added dropwise to a solution containing 1.37 g (0.005 mol) 1,6-hexanediol dimethanesulfonate in 10 ml acetonitrile, and the resulting mixture was refluxed for 20 hours. The reaction mixture was evaporated to dryness under reduced pressure and the remaining gum was treated with ether to give a colorless hygroscopic solid. This product was redissolved in a mixture of ethanol, benzene and acetonitrile and the resulting solution evaporated to dryness under reduced pressure. The residue was treated with ether, and the resulting white solid was quickly collected by filtration, washed with anhydrous ether, and dried for 72 hours at 28°C/0.1 mm Hg to give 2.65 g of 1,6-bis -/4-(octyl-amino)-1-pyridinium/hexanedimethanesulfonate as a waxy white solid. Molar weight calculation: Calculated: C 59.44; H 9.09; N 8.16; S 9.33

Found: C 59.14; H 9.31; N 8.02; S 9.33

Example_el_1_6

The same procedure as described in example 9 C was used, but 14.24 g (0.08 mol) of 4-(hexylamino)-pyridine and 8.64 g (0.04 mol) of 1,4-dibromobutane were used, and after treatment of the crude product with a mixture of acetonitrile and acetone gave 20.45 g of 1,4-bis-4-(hexylamino)-1-pyridinium/butane dibromide, m.p. 199-201°C.

Example 17

The same procedure as described in example 9 C was used, but 10.7 g (0.06 mol) of 4-(hexyl-amino)pyridine and 7.32 g (0.03 mol) of 1,6-dibromohexane were used, and after treatment of the crude product with a mixture of ether, acetonitrile and acetone gave a total of 14.90 g of 1,6-bis-(4-(hexylamino)-1-pyridiniumZ-hexanedibromide, m.p. 178-179°C.

Example_el_1_8_

Using the same procedure as described in Example 9 C, but using 10.7 g (0.06 mol) 4-(hexyl-amino)-pyridine and 7.75 g (0.03 mol) 1,7- dibromoheptane, after treating the crude product with a mixture of acetonitrile and acetone, a total of 16.4 g of 1,7-bis-(4-(hexylamino)-1-pyridinium/heptane dibromide, m.p. 157-158°C.

Example_el_1_9

The same procedure as described in example 9 C was used, but 10.7 g (0.06 mol) of 4-(hexylamino)-pyridine and 8.6 g (0.03 mol) of 1,9-dibromononane were used, and a total of 17.15 g of 1,9-bis-(4-(hexylamino)-1-pyridiniumZ-nonanedibromide, m.p. 114-115°C.

Example_el_20

The same procedure as described in example 9 C was used, but 15.4 g (0.08 mol) of 4-(heptylamino)-pyridine and 8.64 g (0.04 mol) of 1,4-dibromobutane were used, and 23 .1 g of 1,4-bis-(4-(heptylamino)-1-pyridinium/butane dibromide, m.p. 229-230°C.

Example_el_21_

The same procedure as described in example 9 C was used, but 10.0 g (0.052 mol) 4-(heptyl-amino) pyridine and 6.7 g (0.026 mol) 1,7-dibromoheptane were used, and a total of 14.05 g 1,7-bis-((4-heptylamino)-1-pyridinium"-heptanedibromide, m.p. 142-14 3°C.

Example_el_22

Using the same method as described in example 9 C, but using 11.6 g (0.06 mol) 4-(heptyl-amino)pyridine and 8.2 g (0.03 mol) 1,8-dibromooctane, after recrystallization from acetonitrile and ether, a total of 18.6 g of I, 8-bis-(4-(heptylamino)-1-pyridinium/octanedibromide, m.p. 161-162°C.

Example_el_23

The same procedure as stated in example 2 was used, but 5.0 g (0.0076 mol) of 1,8-bis-[4-(heptylamino)-1-pyridinium/octane dibromide were used and 4.1 g of the corresponding dichloride, m.p. 206-208°C.

<Example>_<el>_<24>

The same procedure as stated in example 9 C was used, but 15.4 g (0.08 mol) of 4-(heptylamino)pyridine and II, 44 g of 1,9-dibromononane were used, and 21.3 g of 1,9 -bis-(heptylamino)-1-pyridinium/nonane dibromide, m.p. 115-116°C.

Example_el_25

The same method as described in example 2 was used, but 5.0 g (0.0075 mol) of 1,9-bis-[4-(heptylamino)-1-pyridinium/nonandibromide were used, and 4.2 g of the corresponding dichloride, m.p. 154-155°C.

Example_el_26

The same procedure as indicated in the example was used

9 C, but used 15.4 g (0.08 mol) 4-(heptylamino)pyridine and 12.0 g (0.04 mol) 1,10-dibromodecane, and obtained 25.7 g of 1,10-bis -/4-(heptylamino)-1-pyridinium/decanedibromide, m.p. 163-165°C.

Example_27

The same procedure as described in example 2 was used, but 5.0 g (0.0073 mol) of 1,10-bis-[4-(heptyl-amino)-1-pyridinium/decanedibromide were used, and 4.35 g were produced of the corresponding dichloride, m.p. 209-210°C.

Example_el_28

A stirred suspension of 30 ml of a synthetic anion exchange resin in the hydroxide form ("Amberlite IRA 400") in 150 ml of water was added dropwise with 48% aqueous hydrofluoric acid until the mixture became acidic. After stirring for another half hour, the suspension was poured into a column. The column was drained and the resin washed with a solution containing 15 ml of 48% aqueous hydrofluoric acid in 185 ml of distilled water. The resin was then washed with distilled water until the eluate was slightly acidic, and then successively with 20%, 40% and 50% aqueous methanol and finally with absolute methanol until the eluate was neutral. On top of this column of the ion exchange resin in the fluoride form was now added a solution containing 0.25 g (0.000365 mol) of 1,10-bis-(4-(heptylamino)-1-pyridinium/decanedibromide in 1 ml of methanol). A total of five fractions of 15 ml were collected. The first three fractions were combined and evaporated to dryness

hot under reduced pressure. The oily residue was dissolved

in a mixture of toluene and ethanol, and the resulting solution evaporated under reduced pressure to dryness. The remaining oil was redissolved in a mixture of benzene and acetone, and the solution concentrated to a small volume. The solid which separated was collected by filtration and dried for 24 hours at 24°C/0.1 mm Hg to give 0.11 g of impure 1,10-bis-[4-(heptylamino)- 1-pyridiniumZ-decane difluoride, m.p. 85-90°C.

Example_el_29

A. A solid mixture containing 115 g (0.5 mol) of N-(4-pyridyl)pyridinium chloride hydrochloride and 119 g (0.66 mol) of n-nonylamine hydrochloride was heated in an oil bath to a temperature of 220°C (internal temperature 190 -194°C), and the resulting liquid stirred at this temperature for 2 hours. The reaction mixture was cooled to 80°C, diluted with

1.2 liters of ice and water, made alkaline with 35% aqueous sodium hydroxide and extracted with chloroform. The chloroform extracts were dried over anhydrous sodium sulfate, treated with decolorizing carbon, filtered and evaporated to dryness under reduced pressure. The remaining viscous oil was cooled to

-78°C and then treated with ether. The resulting solid was collected by filtration and washed with cold ether. The filtrate gave another yield of a solid. The combined solids were redissolved in chloroform, and the resulting solution was treated with decolorizing carbon and filtered. This was repeated once more and the filtrate was then evaporated to dryness under reduced pressure. The remaining semi-solid was treated with ether and cooled to give an almost colorless solid which was collected by filtration, washed with cold ether and dried. This solid was dissolved in chloroform and the resulting solution treated with decolorizing carbon, filtered and evaporated to dryness under reduced pressure. The semi-solid was cooled and treated

with ether to give a colorless solid which was collected by filtration, washed with cold ether and dried to give 51.7 g of 4-(nonylamino)pyridine, m.p. 59-60°C. The filtrate gave a new yield of 11.6 g, m.p. 55-57°C.

B. Alternatively, 4-(nonylamino)pyridine can be prepared as follows: A mixture containing 39.5 g (0.42 mol) 4-aminopyridine, 175 g (1.24 mol) nonylaldehyde, 5.0 g 10% palladium- on-carbon hydrogenation catalyst and sufficient absolute ethanol to give a total volume of 60 ml was heated and hydrogenated under an initial hydrogen pressure of 4.3 kg/cm 2 until the absorption of hydrogen stopped. The reaction mixture was filtered to remove the catalyst and the filtrate evaporated to dryness under reduced pressure. The remaining oil was vacuum distilled to remove any nonyl alcohol that may have been produced. The fraction boiling at 63-64°C/4.5 mm was collected and set aside. The residue was treated with ether and cooled to -78°C. The solid that separated was collected by filtration and washed with cold ether. This product was dissolved in chloroform, the resulting solution treated with decolorizing carbon, filtered, after which the filtrate was evaporated to dryness. The residue was treated with ether and cooled to -78°C.

The solid was collected by filtration, washed with

cold ether and air-dried, after which 27.0 g of 4-(nonyl-amino)-pyridine were obtained, m.p. 57-59°C.

C. A stirred suspension of 11.0 g (0.05 mol) 4-(nonyl-amino)-pyridine in 150 ml acetonitrile was heated until a clear homogeneous solution was obtained. To this clear solution was added dropwise a solution containing 6.8 g (0.025 mol) of 1,8-dibromooctane in 50 ml of acetonitrile, and the resulting mixture was refluxed for 19 hours and a solid was precipitated. After cooling, the substance was filtered off, redissolved in methanol and the solution treated with decolorizing carbon, filtered and evaporated to dryness under reduced pressure. Treatment of the remaining oil with ether containing a small amount of acetonitrite gave a colorless crystalline substance which was collected by filtration and dried to give 15.5 g of 1,8-bis-[4-(nonylamino)-1-pyridinium/octane dibromide , m.p. 178-179°C.

Example_el_30

The same procedure as in example 29 C was used, but 3.54 g (0.026 mol) of 4-(propylamino)pyridine and 3.90 g (0.013 mol) of 1,10-dibromodecane were used, and 5.19 g of 1,10- bis-(4-(propylamino)-1-pyridinium/decanedibromide, m.p. 206-207°C.

Example_el_31_

The same procedure as in example 29 C was used, but 14.24 g (0.08 mol) of 4-(hexylamino)pyridine and 9.20 g (0.04 mol) of 1,5-dibromopentane were used, and after recrystallization from acetonitrile and acetone in total 12.3 g 1,5-bis-(4-(hexylamino)-1-pyridinium/pentanedibromide, m.p. 155-156°C.

Example_el_32

The procedure from example 2 9 C was used, but 10.7 g (0.06 mol) of 4-(hexylamino)pyridine and 8.2 g (0.03 mol) of 1,8-dibromooctane were used, and a total of 16.3 g 1,8-bis-(4-(hexylamino)-1-pyridinium/octane dibromide, m.p. 180-181°C.

Example_el__3 3

The same procedure as in Example 2 9 C was used, but 12.5 g (0.07 mol) of 4-(hexylamino)pyridine and 10.5 g (0.035 mol) of 1,10-dibromodecane were used and 16.0

g 1,10-bis-(4-(hexylamino)-1-pyridinium/decanedibromide, m.p. 148-149°C.

Example_el_34

The procedure was as described in example 2 9 C,

but 13.4 g (0.076 mol) of 4-(cyclohexylamino)-pyridine and 10.34 g (0.038 mol) of 1,8-dibromooctane were used, and 19.1 g of 1,8-bis-/4-( cyclohexylamino)-1-pyridinium 7-octane dibromide, m.p. 270-271°C.

Example_el_35

The procedure as stated in Example 2 9 C was used, but 13.4 g (0.076 mol) of 4-(cyclohexylamino)pyridine and 10.8 g (0.038 mol) of 1,9-dibromononane were used, and 16.3 g of 1.9 - bis-(4-(cyclohexylamino)-1-pyridinium 7-nonane dibromide, m.p. 149-151°C.

Exam1_36

The procedure was as stated in example 2 9 C, but 13.4 g (0.076 mol) of 4-(cyclohexylamino)pyridine and 11.4 g (0.038 mol) of 1,10-dibromodecane were used, and 19.0 g of 1.10 - bis-(4-(cyclohexylamino)-1-pyridinium 7 decanedibromide, m.p. 226-227°C.

Example_el_37

A. A mixture containing 298.0 g (1.33 mol) of N-(4-pyridy1)pyridinium chloride hydrochloride and 322 g (2 mol) of 2-ethylhexylamine hydrochloride was heated for 2 hours with stirring in an oil bath at a temperature of 215 °C. The mixture was cooled to 60°C, diluted with 500 ml of water and kept cold by adding ice while making it alkaline with 35% aqueous sodium hydroxide. The alkaline mixture was extracted with ether, and the ether extract was dried over anhydrous sodium sulfate and evaporated to dryness. The remaining oil was distilled under reduced pressure and 101.0 g of 4-(2-ethylhexylamino)pyridine was obtained, b.p. 145-150°C/0.9 mm.

B. Alternatively, 4-(2-ethylhexylamino)pyridine can be prepared as follows:

A stirred solution containing 800 g (8.4 mol) 4-aminopyridine and 1500 ml triethylamine in 6.4 1 dichloromethane was added over 3 hours to a solution containing 1610 g (10.0 mol) 2-ethylhexanoyl chloride in 1.6 1 dichloromethane . During the addition, the temperature was kept at 15°C. After the addition was complete, the mixture was heated on a steam bath for 2 hours. After cooling, the reaction mixture was washed with water, dried over anhydrous sodium sulfate and treated with decolorizing carbon and filtered. Evaporation of the filtrate gave 1843 g of N-(4-pyridyl)-2-ethylhexanamide.

A mixture containing 100 g (2.63 mol) of lithium aluminum hydride in 2 L of tetrahydrofuran was added at a rate sufficient to maintain gentle refluxing a solution containing 570 g (2.62 mol) of N-(4-pyridyl)- 2-ethylhexanamide in 4 1 tetrahydrofuran. After the addition was finished, which took approx. 3 hours, the reaction mixture was refluxed for 7 hours. After cooling, the mixture was successively treated with 100 ml of water, 100 ml of 15% aqueous sodium hydroxide and 300 ml of water. The solids were removed by filtration, and the solvent was evaporated from the filtrate under reduced pressure. The remaining oil was combined with the product from a similar experiment, and then vacuum distilled to give 837 g of 4-(2-ethylhexylamino)pyridine, b.p. 135-160°C/0.2 mm. C. A stirred hot solution containing 10.3 g (0.05 mol) 4-(2-ethylhexylamino)pyridine in 50 ml acetonitrile was added dropwise to a solution containing 8.2 g (0.025 mol) 1,12-dibromodecane in 170 ml of acetonitrile, and the resulting mixture was heated for 20 hours under reflux. On cooling to 0°C, a first yield of the product was obtained and this was collected by filtration. Evaporation of the filtrate and treatment of the residue with ether gave a new yield. The combined yields were dissolved in methanol, the resulting solution treated with decolorizing carbon, filtered, after which the filtrate was evaporated to dryness under reduced pressure. The remaining oil was cooled and treated with ether to give a slightly colored solid. Recrystallization from acetonitrile and ether followed by treatment of the product with ether followed by acetonitrile gave, after drying for 72 hours under vacuum at 60°C, a total of 14.7 g of 1,12-bis-(4-(2-ethylhexylamino)-1 - pyridinium/dodecanedibromide as colorless granules, m.p. 146-147°C.

Example_38

A. A mixture containing 353.5 g (1.72 mol) of 4-(2-ethylhexylamino)pyridine and 205 g (0.86 mol) of 1,12-dichlorododecane was heated at 120°C. The heat source was removed, the temperature of the now exothermic reaction continued to rise to 180-190°C. When the temperature had fallen to 135°C, 1 liter of acetonitrile was carefully added, and the mixture was boiled under reflux until a clear solution was obtained. The hot acetonitrile solution was combined with corresponding solutions from two previous experiments, treated with decolorizing carbon and filtered. The filtrate was cooled and the precipitated product was collected by filtration and washed with cold acetonitrile. Two recrystallizations from acetonitrile gave 970 g of 1,12-bis-(4-(2-ethylhexylamino)-1-pyridinium-7-dodecanedichloride, m.p. 168-171°C.

B. Alternatively, one can use the same method as described in example 2, but one must use 3,Og (0.00405 mol) 1,12-bis-[4-(2-ethylhexylamino)-1-pyridinium 7-dodecane dibromide, and then produced 2.0 g of the corresponding dichloride, m.p. 172-173°C.

Example_39

The procedure was as indicated in example 37, but 10.3 g (0.05 mol) of 4-(octylamino)pyridine and 6.45 g (0.025 mol) of 1,7-dibromoheptane were used and 14.85 g of 1, 7-bis-4-(octylamino)-1-pyridinium 7heptanedibromide, m.p. 129-131°C.

Eczema gel_40

A. The procedure from example 37 C was used, but 11.1 g (0.054 mol) of 4-(octylamino)pyridine and 7.72 g (0.027 mol) of 1,9-dibromononane were used, and 17.0 g of 1, 9-bis-(4-(octylamino)-1-pyridinium/nonanedibromide, m.p. 117-119°C.

B. The corresponding dichloride can be prepared as indicated in Example 2, and it had a melting point of 161-162°C.

Example_41_

The procedure was as in example 37 C, but 10.3 g (0.05 mol) of 4-(octylamino)pyridine and 8.2 g (0.025 mol) of 1,12-dibromododecane were used, and 15.2 g of 1, 12-bis-(4-(octylamino)-1-pyridinium/dodecanedibromide, m.p. 119-120°C.

Example_el_42

The procedure was as in example 37 C, but 5.8 g (0.028 mol) of 4-(octylamino)pyridine and 5.0 g (0.014 mol) of 1,14-dibromotetradecane were used, and 9.3 g of 1,14 -bis-(4-(octylamino)-1-pyridinium/tetradecanedibromide, m.p. 113-115°C.

Example_el_43

The procedure was as indicated in example 37 C, but 11.0 g (0.05 mol) 4-(nonylamino)-pyridine and 6.1 g (0.025 mol) 1,6-dibromohexane were used, and 15.2 g 1,6-bis-(4-(nonylamino)-1-pyridinium/hexanedibromide, m.p. 152-154°C.

Example_el_44

The procedure was as in example 4, but 6.5 g (0.0095 mol) of 1,6-bis-[4-(nonylamino)-1-pyridinium/T hexanedibromide were used and a total of 4.95 g of the corresponding dichloride was obtained , m.p. 194-195°C.

Exerngel_45

The procedure was as indicated in example 37 C, but 8.8 g (0.04 mol) of 4-(nonylamino)pyridine and 5.2 g (0.02 mol) of 1,7-dibromoheptane were used, and 12 was prepared, 2 g of 1,7-bis-(4-(nonylamino)-1-pyridinium/heptanedibromide, m.p. 132-134°C.

Example_el_46

The procedure was from example 37 C, but 11.0 g (0.05 mol) of 4-(nonylamino)pyridine and 7.15 g (0.025 mol) of 1,9-dibromononane were used, and 15.7 g of 1, 9-bis-4-(nonyl-amino)-1-pyridinium 7-nonanedibromide, m.p. 121-122°C.

Example_el_47

The procedure was as indicated in example 37 C, but 11.0 g (0.05 mol) of 4-(nonylamino)pyridine and 7.5 g (0.025 mol) of 1,10-dibromodecane were used, and 15.63 g were produced 1,10-bis-(4-(nonylamino)-1-pyridinium/decanedibromide, m.p. 172-173°C.

Example_48

The procedure from example 37 C was used, but 10.12 g (0.046 mol) of 4-(nonylamino)pyridine and 7.54 g (0.023 mol) of 1,12-dibromododecane were used, and 16.4 g of 1,12- bis-(4-(nonylamino)-1-pyridinium/dodecanedibromide, m.p. 105-106°C.

Example_el_49

A stirred hot solution containing 12.4 g (0.06 mol) 4-(2-ethylhexylamino)pyridine in 100 ml acetonitrile was added dropwise. A solution containing 6.9 g (0.03 mol) 1,5-dibromopentane in 25 ml of acetonitrile, and the resulting solution boiled for 20 hours under reflux. The reaction mixture was cooled and diluted with ether until slightly cloudy. Further cooling and stirring gave a solid precipitate which was filtered off and washed with a cold mixture of acetonitrile and ether. The solid was dissolved in ethanol, and the resulting solution treated with decolorizing carbon and filtered. Evaporation of the filtrate gave a pale yellow viscous oil which crystallized from acetonitrile. The resulting solid was collected by filtration, washed with cold acetonitrile and dried for 24 hours under vacuum at 90°C to give 13.6 g of 1,5-bis-(4-(2-ethylhexylamino)-1-pyridinium) pentane dibromide, m.p. 150-151°C.

Example_50

The method from example 49 was used, but 12.4 g (0.06 mol) of 4-(2-ethylhexylamino)pyridine and 7.32 g (0.03 mol) of 1,6-dibromohexane were used, and a total of 16.1 g 1,6-bis-(4-(2-ethylhexylamino)-1-pyridinium/hexane dibromide, m.p. 208-209°C.

Example<el>_<5>2

The procedure was as in example 49, but 12.4 g (0.06 mol) of 4-(2-ethylhexylamino)pyridine and 7.75 g (0.03 mol) of 1,7-dibromoheptane were used, and 17 was prepared, 9 g of 1,7-bis-[4-(2-ethylhexylamino)-1-pyridinium/heptanedibromide, m.p. 219-220°C.

Example_el_52

The procedure was as stated in example 49, but 12.4 g (0.06 mol) of 4-(2-ethylhexylamino)pyridine and 8.2 g (0.03 mol) of 1,8-dibromooctane were used, and 15 was prepared .9 g of 1,8-bis-(4-(2-ethylhexylamino)-1-pyridinium/octanedibromide, m.p. 160-161°C.

Example_el_53

The procedure was as indicated in example 49, but 12.4 g (0.06 mol) of 4-(2-ethylhexylamino)pyridine and 8.6 g (0.03 mol) of 1,9-dibromononane were used, and 15 was prepared .2 g of 1,9-bis-[4-(2-ethylhexylamino)-1-pyridinium/nonane dibromide, m.p. 158-159°C.

Example_el_54

The procedure was as indicated in example 49, but 12.4 g (0.06 mol) of 4-(2-ethylhexylamino)pyridine and 9.0 g (0.03 mol) of 1,10-dibromodecane were used, and 17 was obtained .4 g 1,10-bis-[4-(2-ethylhexylamino)-1-pyridinium/decanedibromide, m.p. 162-163°C.

Example_55

The procedure was as stated in example 2, but 5.0 g of 1,10-bis-[4-(2-ethylhexylamino)-1-pyridinium]-decane dibromide was used and 4.11 g of the corresponding dichloride was produced, m.p. 191-192°C.

Example_el_56

A stirred hot solution containing 12.0 g (0.06 3 mol) 4-(heptylamino)pyridine in 100 ml acetonitrile was added dropwise to a solution containing 7.4 g (0.032 mol) 1,5-dibromopentane in 25 ml acetonitrile, and the resulting mixture boiled for 19 hours under reflux. The reaction mixture was cooled in ice, and ether was gradually added until a colorless solid precipitated. This was collected by filtration, recrystallized from acetonitrile and ether and dried for 48 hours at 90°C/1 mm Hg to give 15.9 g of 1,5-bis-(4-(heptylamino)-1-pyridiniumZpentanedibromide, m.p. . 153-154°C.

Example_el_57

The method from example 56 was used, but 19.2 g (0.1 mol) of 4-(heptylamino)pyridine and 12.2 g (0.05 mol) of 1,6-dibromohexane were used, and 27.5 g of a raw product. Recrystallization of a 15 g sample from acetonitrile and ether gave 11.45 g of 1,6-bis-(4-(heptylamino)-1-pyridinium-7-hexanedibromide, m.p. 14 9-150°C.

Example_el_58

A. A suspension of 24.0 g of impure 1,6-bis-(4-(heptylamino)-1-pyridinium/hexane dibromide in 500 ml of water was made alkaline with 3N aqueous sodium hydroxide and then extracted with chloroform. The chloroform extracts were dried over anhydrous sodium sulfate and evaporated to dryness under reduced pressure. The remaining oil was dissolved in methanol, and the resulting solution acidified with methanesulfonic acid and evaporated to dryness under reduced pressure. The residue was redissolved in methanol, treated with decolorizing carbon, filtered and evaporated to dryness under vacuum to give an oily residue which was treated with ether and then acetonitrile to give 18.2 g of a gummy solid. This was dissolved in water, and the solution made alkaline with 35% aqueous sodium hydroxide and then extracted with chloroform. The chloroform extracts were dried under anhydrous sodium sulfate and evaporated to dryness under reduced pressure. The resulting solid was successively treated with ether and acetonitrile, collected by filtration and dried to give 16.3 g of a light brown solid, m.p. 105-108°C. This was dissolved in 100 ml of methanol, and the solution acidified with methanesulfonic acid. Evaporation to dryness under reduced pressure gave a viscous oil which was dissolved in 20 ml of methanol and treated portionwise with 150 ml of water. The resulting suspension was cooled in ice, and the solid was collected by filtration and washed with cold water. The material was then stirred in hot acetone, cooled, collected by filtration, washed with cold acetone and then dried for 48 hours at 95°C/1 mm Hg to give 10.8 g of a light brown solid, m.p. 163-165°C. This product gave a positive chloride ion test with silver nitrate, and an NMR spectrum indicated an absence of the methanesulfonate group.

B. A suspension of 14.0 g of 1,6-bis-(4-(heptylamino)-1-pyridinium/hexanedibromide in 500 ml of water was made alkaline with 35% aqueous sodium hydroxide and then extracted with chloroform. The chloroform extracts were dried over anhydrous sodium sulfate and evaporated to dryness under reduced pressure. The partially solid residue was dissolved in 1 liter of acetonitrile-benzene, and the solution evaporated to dryness under vacuum. This procedure was repeated three times. The final residue was dissolved in 50 ml of acetonitrile, and the resulting solution diluted with 50 ml of benzene and cooled in ice, and after filtration, 5.3 g of a pale brown substance was obtained. The filtrate gave a new yield of 4.8 g. The combined yields were combined and dissolved in 50 ml of acetonitrile. Dilution with ether precipitated a solid which was filtered off and dried for 48 hours at 95°C/1 mm Hg to give 8.85 g of a light brown substance, m.p. 174-176°C. This product also gave a positive chloride ion test with silver nitrate. C. The products from parts A and B above were combined, mixed with 300 ml of water and heated until a homogeneous solution was obtained. The solution was filtered off, and the filtrate treated with 50 ml of 12N hydrochloric acid. The resulting suspension was concentrated under reduced pressure and the residue treated with ice. The solid product was heated by filtration, washed with cold water and dried. The product was then dissolved in acetone, the solution diluted with a mixture of benzene and ethanol and the whole evaporated to dryness under vacuum. The solid residue was suspended in 100 ml of acetone and then diluted with ether and filtered, whereupon after drying for 48 hours at 105°C and 1 mm Hg and 72 hours at 115°C and 1 mm Hg, a total of 16.3 g was obtained of an impure 1,6-bis-(4-(heptylamino)-1-pyridinium/- hexane dichloride as a white solid, m.p. 176-178°C.

Example_el_59

The method from example 56 was used, but 10.30 g (0.050 mol) of 4-(2-ethylhexylamino)pyridine and 5.4 g (0.025 mol) of 1,4-dibromobutane were used, and a total of 14.9 g of 1,4- bis-[4-(2-ethylhexylamino)-1-pyridinium-7-butane dibromide, m.p. 245-246°C.

Example_el_60

A. A mixture containing 229 g (1.0 mol) of N-(4-pyridyl)-pyridinium chloride hydrochloride and 244 g (1.26 mol) of n-decylamine hydrochloride was stirred and heated for approx. 2.5 hours at 190-195°C. The reaction mixture was then cooled slowly to 40°C and diluted with 2 1 of water. The resulting solution was cooled by the addition of ice and made alkaline with 200 ml of 35% aqueous sodium hydroxide. A dark solid was obtained and this was filtered off and washed with cold water. The substance was then dissolved in 1 liter of chloroform and the solution treated with decolorizing carbon and filtered. The filtrate was evaporated under reduced pressure, and the residue was treated with 150 ml of ether. The solid was redissolved in chloroform, and the solution treated with decolorizing carbon and filtered. The filtrate was again treated with decolorizing carbon and filtered. The filtrate was evaporated to dryness under reduced pressure and the solid treated with ether. Recrystallization from acetonitrile gave, drying under vacuum, 96.1 g of 4-(decylamino)pyridine, m.p. 71-73°C.

B. A stirred hot solution containing 12.2 g (0.052 mol) of 4-(decylamino)pyridine in 150-170 mL of acetonitrile was added dropwise to a solution containing 6.35 g (0.026 mol) of 1,6-dibromohexane in 60 mL acetonitrile, and the resulting mixture heated for approx. 20 hours during reflux. The reaction mixture was then cooled in ice, and the precipitated solid was collected by filtration and washed with cold acetonitrile. The product obtained was dissolved in methanol, and the resulting solution treated with decolorizing carbon and filtered. The filtrate was evaporated to dryness under reduced pressure, and the residue was treated with 50 ml of cold ether, collected by filtration and dried for 2 days over phosphorus pentoxide at 70°C and 0.1 mm Hg. This gave 14.6 g of 1,6-bis-(4-(decyl-amino)-1-pyridinium/hexane dibromide, m.p. 138-140°C.

Example_el_61_

The procedure from Example 60 B was used, but 12.2 g (0.052 mol) of 4-(decylamino)pyridine and 6.7 g (0.026 mol) of 1,7-dibromoheptane were used, and 16.0 g of 1,7-bis was obtained -/4-(decylamino)-1-pyridinium/heptanedibromide, m.p. 145-147°C.

Example_el_62

The procedure was as indicated in example 60 B, except that 11.7 g (0.050 mol) of 4-(decylamino)pyridine and 6.8 g (0.025 mol) of 1,8-dibromooctane were used, and 16.9 g of 1,8 -bis-(4-(decylamino)-1-pyridinium/octane dibromide, m.p. 180-182°C.

Example_el_63

The procedure was as in Example 60 B, but 11.7 g (0.050 mol) of 4-(decylamino)pyridine and 7.15 g (0.025 moi) of 1,9-dibromononane were used, and 15.1 g of 1,9- bis-[4-(decyl-amino)-1-pyridinium/nonanedibromide, m.p. 124-126°C.

Example_64

The procedure was as described in Example 60 B, but 11.2 g (0.048 mol) of 4-(decylamino)pyridine and 7.2 g (0.024 mol) of 1,10-dibromodecane were used, and 14.6 g of 1,10 -bis-/ 4-(decylamino)-1-pyridinium/decanedibromide, m.p. 17 3— 174°C.

Example_el_65

The procedure was as indicated in example 60 B, but

11.2 g (0.048 mol) of 4-(decylamino)pyridine and 7.9 g (0.024 mol) of 1,12-dibromododecane were used, and 16.5 g of 1,12-bis-[4-(decylamino)- 1-pyridinium/dodecane dibromide, m.p. 102-106°C.

Example 66

A stirred hot solution containing 13.6 g (0.052 mol) of 4-(dodecylamino)pyridine in 140 ml of acetonitrile was added dropwise to a solution containing 6.34 g (0.026 mol) of 1,6-dibromohexane in 50 ml of acetonitrile, and the resulting mixture boiled under reflux overnight. The mixture was cooled and the solid was collected by filtration. The combined solid was dissolved in absolute ethanol, and the solution treated with decolorizing carbon and filtered. The filtrate was evaporated to dryness under vacuum to give a white solid which was stirred in ether, filtered off and dried at 60°C/0.1 mm Hg to give 17.63 g of 1,6-bis-/4 -(dodecylamino)-1-pyridinium/hexanedibromide, m.p. 164-165°C.

Example_el_67

The procedure from Example 66 was used, but 13.6 g (0.052 mol) of 4-(dodecylamino)pyridine and 6.71 g (0.026 mol) of 1,7-dibromoheptane were used, and 18.03 g of 1,7-bis- /4-(dodecylamino)-1-pyridinium/heptanedibromide, m.p. 148-150°C.

Example_el_68

The procedure was as stated in example 66, but 12.59 g (0.048 mol) of 4-(dodecylamino)pyridine and 6.53 g (0.024 mol) of 1,8-dibromooctane were used, and 16.18 g of 1,8- bis-1_ 4-(dodecylamino)-1-pyridinium/octanedibromide, m.p. 184-185°C.

Example_el_6 9

The procedure was as indicated in example 66, but 12.59 g (0.048 mol) of 4-(dodecylamino)pyridine and 6.86 g (0.024 mol) of 1,9-dibromononane were used and 19.35 g of 1,9-bis -/4-(dodecylamino)-1-pyridinium/nonanedibromide, m.p. 134-135°C.

Example_el_70

The procedure was as stated in example 66, but 12.59 g (0.048 mol) of 4-(dodecylamino)pyridine and 7.2 g (0.024 mol) of 1,10-dibromodecane were used and 18.08 g of 1,10-bis -/4-(dodecylamino)-1-pyridinium/decanedibromide, m.p. 178-180°C.

Example_el_71

The procedure was as in Example 66, but 11.54 g (0.044 mol) of 4-(dodecylamino)pyridine and 7.22 g (0.022 mol) of 1,12-dibromododecane were used and 17.68 g of 1,12-bis- /4-(dodecylamino)-1-pyridinium/dodecanedibromide, m.p. 75-77°C.

Example_72

A. A stirred hot solution containing 21.0 g (0.102 mol) 4-(p_-chlorophenylamino) pyridine in 200 ml N,N-dimethylformamide was added dropwise to a solution containing 12.45 g (0.051 mol) 1.6 -dibromohexane in 50 ml of acetonitrile, and the resulting mixture was heated for 4 hours on a steam bath. On cooling to room temperature, a solid was precipitated. The mixture was diluted with 150 ml of acetonitrile and further cooled on ice. The solid was filtered off and air-dried and 27.2 g of 1,6-bis-[4-(p-chlorophenylamino)-1-pyridini-um-hexanedibromide were obtained, m.p. 148-150°C.

B. A methanol solution of the corresponding anhydrobase was acidified with a methanesulfonic acid and evaporated to dryness under vacuum. The remaining oil was crystallized from acetone and methanol and after drying for 48 hours at 75°C/0.1 mm Hg, a total of 25.2 g of 1,6-bis-[4-(p_-chlorophenylamino)-1-pyridinium? -hexane dimethanesulfonate, m.p. 108-110°C.

Example_el_73

A. A stirred hot solution containing 21.0 g (0.102 mol) 4-(p-chlorophenylamino)pyridine in 200 ml N,N-dimethylformamide was added dropwise to a solution containing 13.9 g (0.051 mol) 1.8 -dibromooctane in 50 ml of acetonitrile, and the resulting mixture heated for a total of 1.5 hours on a steam bath. The reaction mixture was then diluted with 100 ml of acetonitrile and heating was continued for a further 2.5 hours when 100 ml of acetonitrile was added. After reheating for 2 hours, the mixture was cooled, and the solid that had precipitated was filtered off, washed with a mixture of acetonitrile and ether and dried, and 30.1 g of 1,8-bis-/4-(p -chlorophenyl-amino)-1-pyridinium/octanedibromide, m.p. 245-247°C.

B. A methanol solution of the corresponding anhydrobase was acidified with methanesulfonic acid and then evaporated to dryness under vacuum. The remaining oil was dissolved in acetonitrile, and the solution treated with acetone until it became cloudy, followed by clarification with a small amount of methanol and then cooled. The solid that precipitated was collected and recrystallized from acetonitrile and acetone to give, after drying for 36 hours at 80°C and 0.1 mm Hg, a total of 23.5 g of 1,8-bis-(4-(p-chlorophenylamino) )-1-pyridinium/octandimethanesulfonate, m.p. 164-165°C.

Exe<mp>e<l>_<74>

A. A stirred hot solution containing 21.0 g (0.102 mol) 4-(p-chlorophenylamino)pyridine in 200 ml N,N-dimethylformamide was added dropwise to a solution containing 15.3 g (0.051 mol) 1.10 -dibromodecane in 50 ml of acetonitrile, and the mixture was heated on a steam bath for 3.5 hours. The reaction mixture was then evaporated to dryness under reduced pressure, and the oil was crystallized from methanol and acetonitrile. The solid product was filtered off and washed with a cold mixture of acetonitrile and ether, yielding 28.0 g of 1,10-bis-(4-(p-chloro-phenylamino)-1-pyridinium/decanedibromide, m.p. 225-230°C.

B. A methanol solution of the corresponding anhydrobase was acidified with a methanesulfonic acid and evaporated to dryness under vacuum. The remaining oil was crystallized from acetonitrile and ether. The crude solid was dissolved in methanol, and the solution treated with decolorizing carbon and filtered. Evaporation of the filtrate gave an oil which was suspended in a mixture of acetonitrile and acetone to give an impure solid. Recrystallization from methanol and ether gave, after drying at 48 hours at 95°C and 0.1 mm Hg, a total of 18.4 g of 1,10-bis-(4-(p-chlorophenylamino)-1-pyridinium/decandimethanesulfonate, m.p. . 202-204°C.

Example_el_75

A stirred hot solution containing 10.0 g (0.049 mol) of 4-(p-chlorophenylamino)pyridine in a mixture of 125 ml of N,N-dimethylformamide and 50 ml of acetonitrile was added dropwise to a solution containing 6.45 g of 1,7- dibromoheptane in 25 ml of acetonitrile, and the mixture was refluxed for 19 hours. The reaction mixture was then evaporated to dryness under reduced pressure, and the remaining oil crystallized from ethanol and acetonitrile. The solid was dissolved in methanol, and the solution treated with decolorizing carbon and filtered. The filtrate was evaporated to dryness under vacuum, and the remaining oil recrystallized from ethanol and acetonitrile. The product was filtered off and dried for 36 hours at 105°C/0.1 mm Hg, whereby 10.4 g of 1,7-bis-[4-(p-chloro-phenylamino)-1-pyridinium/heptanedibromide, m.p. . 202-204°C.

Example_76

The procedure from Example 75 was used, but 10.0 g (0.04 9 mol) of 4-(p-chlorophenylamino)pyridine and 7.15 g (0.025 mol) of 1,9-dibromononane were used and 11.2 g of 1, 9-bis-[4-(p-chlorophenylamino)-1-pyridinium/nonane dibromide, m.p. 178-179°C.

Example_el_77

A warm stirred solution containing 11.52 g

(0.06 mol) of 4-(heptylamino)pyridine in 100 ml of acetonitrile was added in small amounts to a solution containing 7.92 g

(0.03 mol) of α,α'-dibromo-p-xylene in 150 ml of acetonitrile. When the addition was finished, there was a large mass of useless crystals separated from the solution. The reaction mixture was refluxed for 6 hours. After cooling to room temperature, the solid product was collected by filtration, washed with acetonitrile and ether, and combined with 3.1 g from a previous experiment, and dried for 28 hours at 100°C/0.1 mm Hg, giving 22 .0 g α,α'-bis-(4-(heptylamino)pyridinium/-p-xylene dibromide, m.p. 297-298°C.

Example_el_78

The procedure from example 77 was used, but 11.6 g (0.065 mol) 4-(hexylamino)pyridine and 8.7 g (0.033 mol) a,a<1->dibromo-p-xylene were used and the reaction mixture was boiled under baked for 20 hours, and obtained a total of 19.3 g of ot,a'-bis-[4-(hexylamino)pyridinium 7-p-xylene dibromide, m.p. 313-315°C.

Activity against bacteria and fungi for representative examples of the compounds of formula I was determined by

using a modification of the autotiter method described by Goss, et al. Applied Microbiology 16 (9) 1,414-1,416 (1968) where a 1000 mcg/ml solution of the test compound was prepared. 0.1 ml of the sample solution was added to the first cup in the so-called Autotray apparatus. Activation of the autotiter was initiated by a sequence of operations where 0.05 ml of the sample compound solution was withdrawn from the cup using a microtiter transfer loop and diluted in 0.05 ml of sterile water. Then 0.05 ml of an inoculated semi-synthetic medium (glucose) of double strength is automatically added to each cup. It all results in a final concentration that varies from 500 to 0.06 mcg/ml in double increments. The Autotray apparatus is then incubated for 18-20 hours at 37°C, after which the individual cups are examined visually for growth, which can be detected by turbidity, and the concentration of the last sample in the series

that shows no growth or no turbidity is given as the minimal inhibitory concentration (MIC) in mcg/ml. The compounds were thus tested as solutions against a number of gram-positive and gram-negative bacteria including Staphylococcus aureus, Proteus mirabilis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Streptococcus pyogenes, and against fungi such as Aspergillus niger, Candida albicans and Trichophyton mentagrophytes.

It was further found that many of the compounds with formula

I was also effective against Streptococcus mutans and Actinomyces A-viscosis.

Virucidal activity of representative examples against Herpes simplex type 2 virus was determined in vitro using a method similar to the plate inhibition assay for the detection of specific inhibitors of DNA-containing virus published by E.C. Herrmann, Jr., Proe.Soc.Exp.Biol.Med. 107, 142 (1961), where 2 mg of the test compound was placed on the surface of the growth medium. The compounds corresponding to Examples 3, 5C, 7, 9C, 10, 11, 13, 17, 18, 21, 22, 24, 31, 33, 49, 50, 51, 52, 53, 54, 56, 57, 59 , 75, 76, 77 and 78 were found to be active, while the compounds of Examples 16, 39, 40 and 74B were found to be inactive.

An activity to prevent dental plaque for certain compounds according to the present invention was determined by measuring the ability of these compounds to inhibit the production of dental plaque by Streptococcus mutans OMZ-61 in the following way: A culture medium for the dental plaque-producing Streptococcus mutans OMZ-61 containing 1, 5 g of BBL meat extract, 5 g of sodium chloride, 10 g of dehydrated trypticase, 5 g of sucrose and sufficient distilled water to make a total volume of 1000 ml were adjusted to pH 7.0 and sterilized by membrane filtration. The medium was dispensed aseptically in 10 mL portions into 150 x 16 mm test tubes and stored at refrigerator temperature until used.

Two concentrations of the compound to be tested were prepared by dissolving 100 mg of the compound in 1 mL of distilled water with sufficient 0.1N sodium hydroxide, 10% dimethyl sulfoxide, and 10% N,N-dimethylformamide, and then diluting the resulting solution to 10 ml with distilled water. This 1.0% solution and a 1:10 dilution in distilled water (0.1%) were sterilized by membrane filtration before use.

A sterile piece of a plaque-free natural tooth enamel or synthetic hydroxylapatite was suspended in each concentration of the compound for 2 1-minute periods, each followed by a 1-minute air-drying period. Each piece was then suspended and stirred for 5 minutes in the individual samples containing sterile distilled water (washing). They were then suspended in 10 ml of liquid meat extract medium to which had been added 0.3 ml of a 24-hour anaerobic culture of Streptococcus mutans. The tubes containing the "treated" hydroxylapatite and Streptococcus mutans were then incubated anaerobically at 37°C for 24 hours. The same procedure with 2 1-minute immersions in the solution of the compound each followed by 1-minute air drying and finally 5 minutes of washing, was repeated before resuspending the hydroxylapatite in a fresh tube containing 10 ml of meat extract medium and 0.3 ml of inoculum. At the end of every other 24 hour period, each piece of hydroxylapatite was washed for 1 minute in 3 successive tubes of distilled water. The pieces were then suspended for 1 minute in a solution of F, D & C Red No. 3 dye. This staining was used so that one could more easily identify the development of dental plaque after a 48-hour period of exposure to a dental plaque-producing organism. Staining was followed by a further 10 seconds of washing

to remove excess dye. A possible formation of dental plaque was shown by a clear pink color. The test results were indicated as plaque inhibition (active) or no plaque inhibition (inactive) at the tested concentration.

Active compounds were tested at successively lower doses to determine the minimum effective concentration. In certain cases, it turned out that the inhibition of dental plaque production was due to the organism's growth being inhibited in the culture medium because the compound had leaked from the hydroxylapatite so that an antibacterial level was obtained in the medium.

In those cases where this occurred, the compound was tested at a lower concentration until the growth of the organism in the surrounding medium corresponded to that found in a control medium. Dental plaque may or may not have formed at these lower concentrations.

The fact that the test compound adheres to the tooth surface is of course necessary to prevent the formation of dental plaque, but this can, on the other hand, increase the accumulation of various dyes, e.g. of the type found in coffee, tobacco, dyes in foodstuffs, etc. Therefore, the above-mentioned method was also used to assess the staining potential, i.e. the compound's ability to promote the attachment of coloring agents to the tooth surface. Thus, if there was a residual uniform pale pink color that adhered to the sample surface after a final wash, then this indicates a staining potential at the indicated concentration and was indicated as staining concentration. A uniform pale pink color caused by the test compound can be easily distinguished from the localized bright pink color caused by dental plaque formation. Generally, the preferred compounds advantageously had a staining concentration that was significantly higher than the minimum effective concentration for preventing dental plaque.

Various data for the specified compounds are given in the following table A. Corresponding data for two known compounds, namely 1,8-bis-(4-amino-1-pyridinium)-octanedibromide (reference compound I) and 1,10-bis- (4-Amino-1-pyridinium)-decanedibromide (Reference Compound II) is also included in Table A for comparative purposes. Staining concentrations for representative compounds are listed in Table C.

The efficacy to prevent dental plaque in the presence of sterile human saliva (50%) was determined for representative compounds. The test results are given as minimum effective concentration and are given in Table C.

The acute oral toxicity (ALD5Q) for several representative examples was determined as follows: Groups of 3 young adult male Swiss-Webster albino mice were fasted approx. 4 hours before administration, and then administered the food compound once orally by means of a stomach tube. All mice were observed for 7 days after administration. An autopsy of all mice examined showed no major tissue changes except for the group receiving 1000 mg/kg of the compound of Example 25, where a narrowing of the granular part of the stomach was found in two of the three mice observed. The results are set out in Table D below.

Claims (1)

Bis-pyridinium alkanes suitable for use as disinfectants and for combating dental plaque, characterized in that they have the general formula: where R is an alkyl group with from 3 to 12 carbon atoms, cyclohexyl or p-chlorophenyl, Y is a straight-chain alkylene group with from 4 to 14 carbon atoms, or a p-xylene group; and A is an anion; provided that when R is p-chlorophenyl, Y is a straight chain alkylene group of from 6 to 14 carbon atoms, and when R is unsubstituted cyclohexyl, then Y is an alkylene group of from 8 to 14 carbon atoms.