HU197299B - Process for producing alkyl-esters of thiol-carbaminic acids - Google Patents

Abstract

Prodn. of thiocarbamate esters of formula (I) is effected by reacting an alkyne of formula (II) with a thiocarbamate salt of formula (III), or with a mixt. of an amine of formula (IV), CO and S, or with a mixt. of (IV) and COS, and opt. hydrogenating the prod., opt. after adding an alkylating agent: R3CCR4 (II), R1R2N-CO-SY (III), HNR1R2 (IV) R1 and R2 = H or 1-6C alkyl or 2-6C alkenyl gps. opt. substd. by halogen, O, S and/or N functions, or R1+R2 = opt. substd. 4-6C alkylene; R3 and R4 = H or 1-4C alkyl opt. substd. by halogen, O, S and/or N functions; R5 and R6 = H or R5+R6 = direct bond. Y = primary, sec. or tert. ammonium or alkali metal.

Description

The present invention relates to thiocarbamic acid ethyl esters of the formula (I) wherein R1 and R2 are each independently C1-C6 alkyl, C3-C6 cycloalkyl, or C4-C7 alkylene together. Esters of thiolcarbamic acids are used primarily in agriculture as active ingredients in pesticides, while others are known as insecticides, and some inhibit the growth of certain microorganisms.

Esters of thiol carboxylic acid are disclosed in U.S. Patent Nos. 224,511 and 186,437, German Patent Nos. 2,513,196, and 2,844,305, 7,576,026, 7,825,564, 7,778,832, and 5,195,684.

According to Japanese Patent Specification 746 027 and U.S. Patent Nos. 3,167,571 and 3,151,119, the corresponding thiolcarbamic acid is an alkyl salt of a primary, secondary, or tertiary ammonium or alkaline metal salt thereof prepared by a suitable method. by reaction with a halide.

German Patent Nos. 2,212,766 and 2,117,115 and U.S. Patent 4,066,081, respectively, react an alkyl mercaptan with phosgene and the alkyl chlorothioformoformate thus obtained is a primary, or by reacting with secondary amines to produce thiolcarbamates.

Alkylthiol carbamates are prepared by the reaction of a suitably prepared carbamoyl chloride with an alkyl mercaptan according to U.S. Patent Nos. 2,983,747, 2,913,327 and 3,836,524 and Spanish Patent Nos. 422,149.

According to German Patent Specification 2,703,106, thiol carbamates are formed from dithiocarbamates and dimethyl sulfate and elemental iodine.

According to German Patent No. 2,461,876, O-alkylthiol carbamates can be isomerized to S-alkyl esters by heating with dialkyl sulfates.

The radical addition of olefins and salts of thiolcarbamic acids as described in U.S. Patent 4,071,423 provides thiolcarbamates in extremely low yields.

A common feature of the processes described above, whether using expensive starting materials or phosgene-based methods, is that it poses serious problems of corrosion, health and environmental pollution.

During our research on the preparation of thiolcarbamates, which are inexpensive and simpler, we have surprisingly found that vinyl esters of thiolcarbamic acid can be prepared inexpensively and safely using suitable catalysts, in a suitable solvent, under catalytic conditions, with hydrogen gas in good yields. they can be hydrogenated to esters.

The catalytic hydrogenation of thylcarbamic acid (1-alkenyl) esters to thiolcarbamic acid alkyl esters with hydrogen has not been carried out so far.

According to the present invention, a compound of formula (I), wherein

R1 and R2 are independently

C 1-6 alkyl, or C 3-6 cycloalkyl, or

R1 and R2 taken together are alkylene groups having 4 to 7 carbon atoms, thiol carbamates are prepared by the following formula:

R 1 and R 2 are the vinylthiol carbamates represented by the above formula (I) and are hydrogenated by catalytic hydrogenation in organic chemistry according to methods known per se.

Vinyl thiol carbamates can be prepared according to US 4,613,461 or other known pathways in the literature, e.g. C. G. Overberger, H. Ringsdorf, and N. Weinshenker, J. Org. Chem., 27, 4331-4337 (1962)].

The hydrogen pressure above the reaction mixture is 0.1 to 10 MPa, preferably 1 to 5 MPa.

In a preferred embodiment of the process of the invention, the solvent is lower alkanol, such as methanol, ethanol, normal propanol, isopropanol, normal, secondary or tert-butanol.

The catalysts used are Raney nickel, palladium on platinum or any catalyst suitable for hydrogenation of sulfur-containing materials on alumina, silica gel, charcoal or activated carbon or on natural or artificial zeolites.

The hydrogenation reaction is carried out at a temperature of 125-250 ° C.

The weight ratio of catalyst to substrate is 1:10 to 1:50.

The concentration of the reaction mixture on the substrate is 10-100% by weight, preferably 10-50% by weight.

Alternatively, the ethyl thiolcarbamic acid esters may be prepared from carbon monoxide and sulfur or carbonyl sulfide and from the amine and acetylene of formula (I) wherein R1 and R2 are as defined above, and isolation. without stirring, the resulting reaction mixture is hydrogenated to give the ethyl thiolcarbamic acid ester.

The process of the present invention will now be illustrated, without limiting the scope of the invention, by a few examples.

Examples

Each reaction was performed in a 300 cm ³ stainless steel, heated, pressure-resistant apparatus equipped with an internal stirrer, thermometer, manometer, and sampling tap. The yields of the reactions were determined by gas chromatography.

Example 1

Ν, Ν-d-n-propyl-ethyl tiolkarbamidsav -acetic acid methyl ester

300 cm ³ pressure vessel 100 cm ³ 20 cm ³ metanolbam Ν, Ν-di-n-propyl-vinyl tiolkarbamidsav dissolved. To the resulting solution was added Ig charcoal containing 1% Pd (K-0236 from Heraeus). The pressure vessel was sealed, flushed with hydrogen three times, and finally filled with hydrogen gas (1.5 MPa) and hydrogenated at 240 ° C for 8 hours.

Yield: 82% title compound, 12% starting compound, 6% N, N-di-n-propylforminamide.

The following examples are summarized in tabular form, each reaction being carried out in the same manner as in Example 1.

Table 1

Example A Starting compound vinyl -ester concentration rationality (Wt%) juice- pressure (MPa) catalysts break/ substrate (weight ratio) Catalyst Reaction- Reaction- Yield number Ri R2 aggregatory tem- ture (° C) tion  time (Hours) (%) 2 n-propyl n-propyl 20 5.0 1/20 Heraeus K-0117 240 6 32 3 n-propyl n-propyl 20 0.5 1/20 Heraeus 84,333 160 8 15 4 n-propyl n-propyl 15 1.5 1/20 Raney Ni 200 3 100 5 n-propyl n-propyl 15 1.5 1/20 4.2% Pd, 30% V2O5 200 4 100 6 n-propyl n-propyl 30 0.5 1/15 4.2% Pd, 15% V2O5 on Ϊ-ΑΙ2Ο3 180 4 70 7 n-propyl n-propyl 15 1.5 1/15 • S-Al 2 O 3 support 4.2% Pd, 10% V 2 O 5 200 5 100 8 n-propyl n-propyl 15 1.5 1/15 4.2% Pd, 3% V2O5 on ü-AlzCb 200 4 100 9 n-propyl n-propyl 15 6.0 1/15 4.2% Pd, 1% V2O5 on Ϊ-ΑΙ2Ο3 200 5 100 10 n-propyl n-propyl 30 8.0 1/15 Ϊ-,2Ο3 4.2% Pd, Ϊ-ΑΙ2Ο3 240 3 100 11 ethyl c-hexyl 20 1.5 1/15 support 10 240 4 100 12 ethyl n-butyl 20 1.5 1/15 10 240 4 100 13 R + R2 = - (CH2) 6- 20 1.5 1/15 10 240 5 100 * 14 n-propyl n-propyl 65 1.5 1/15 5.5% PdCh Mor 120 10 25

denite support * 10 cm ³ reactor

Example 15

Ν, Ν-di-n-propyl-tiolkarbajnidsav ethyl ester cm ³ pressure vessel cm catalyst of 1 g EXAMPLE 10 ³ Ν, Ν-di-n-propyl-tiolkarbamidsav vinyl ester 1.5 MPa hydrogen pressure Hydrogenated at 200 ° C for 1 hour.

Yield: 95% title compound, 5% starting material.

Example 16

N, N-di-n-propyl-ethyl ester tiolkarbamidsav cm ³ pressure vessel was dissolved in 2 cm ² (1.5 g, 14 mmol) of di-n-propylamine 10 cm ³ of methanol at -70 ° C 2 cm ³ (3 g, 5 mmol) of carbonylsulfidol are added to the solution. After the vessel was closed, acetylene was pressurized to 1.5 MPa. After stirring at 130 ° C for 10 hours, the mixture was blown off and 0.5 g of charcoal and 1 g of the catalyst of Example 10 were added to the reaction mixture. The vessel was resealed and hydrogenated at 1.5 MPa at 210 ° C for 3 hours. The reaction mixture was blown off and the charcoal and catalyst were filtered off from the reaction mixture, then concentrated under reduced pressure and distilled to give 2.5 g (75%) of N, N-di-n-propylthiolcarbamic acid ethyl ester. Fp2 = 80-85 ° C.

Claims (9)

PATENT CLAIMS A process of the formula (I) wherein: R 1 and R 2 are each independently C 1-6 alkyl, C 3-6 cycloalkyl, or C 4-7 alkylene collectively for the preparation of thiolcarbamic acid ethyl esters, optionally in situ from carbonyl sulfide, acetylene and general formula (III). wherein R 1 and R 2 are by the catalytic hydrogenation of the S-vinyl ester of the thiolcarbamic acid of formula II, wherein R 1 and R 2 are as defined above, wherein: wherein R 1 and R 2 are as defined above, or at least 10% by weight thereof of a C 1 -C 4 alcohol solution in the presence of 2 to 10% by weight of a compound of formula II, which is nickel or palladium, optionally on a support, preferably AkO3, which is 1-30% by weight of vanadium pentoxide and / or 1-10% by weight of nickel or palladium, hydrogenated at a pressure of 0.1 to 10 MPa, 125 to 250 ° C for 0.5 to 10 hours, and the product is recovered from the reaction mixture in a known manner. 2. A process according to claim 1 wherein the catalyst is a finely divided activated carbon containing Ni, Pd or 1-10% Pd. 3. A process according to claim 1, wherein the catalyst support is AkOs containing from 2 to 6% Pd and 3 to 15 L% V 2 O 5 - 0% by weight of the support. 4. A process according to claim 1, wherein the hydrogenation reaction is carried out in the absence of a solvent. 5. A process according to claim 1, wherein the hydrogen gas pressure is from 1 to 10 MPa. 6. The process of claim 1, wherein R 1 and R 2 are n-propyl. 7. The process of claim 1, wherein R1 is ethyl and R2 is n-bu Lile. The process of claim 1, wherein R 1 is ethyl and R 2 is cyclohexyl. 9. A process according to claim 1, wherein R 1 and R 2 together are an alkylene group containing 6 carbon atoms.