DE2042984A1 - 2-aminothiophene-3-carbothioamides - useful as intermediates for dyes and pharmaceuticals - Google Patents

Abstract

Title cpds. of formula (I): (where X and Y are each H, CN or opt. substd. alkyl, aryl or acyl, or X + Y is tri-, tetra- or penta-methylene), which are intermediates for e.g. azo dyestuffs and pharmaceuticals, are prepd. by reacting X-CO-CHY-SH with NC-CH2-CS-NH2, expediently in an inert solvent and/or suspending agent, pref. in the presence of a basic catalyst.

Description

2-Aminothiophene-3-carboxylic acid thioamides The invention relates to compounds of the general formula I. in which X and Y, independently of one another, denote hydrogen, cyano, optionally substituted alkyl, aryl or acyl and X and Y together denote a tri-, tetra- or pentamethylene chain, which are suitable as intermediates for dyes and pharmaceuticals.

As optionally substituted radicals are, for. B. by Cyan, Alkoxr, Aroxy, hydroxy, dialkylamino, acylamino, acyl, acyloxy or aryl substituted alkyl radicals or by halogen, nitro, cyano, alkyl, alkyl, hydroxy, dialkylamino, or acylamino to name substituted aryl radicals.

The optionally substituted alkyl radicals preferably contain a total of 1 to 8 carbon atoms.

In addition to those already mentioned, the following radicals are specifically for Y and X listed: methyl, ethyl, n- or i-propyl, n-, i- or t-butyl, n- or i-Amyl, n-Heyl, ß-Hydroxpäthyl, ß-Cyanoethyl, ß-Methoxy-, ß-Ethoxy- or 3-Butoxyethyl, ß-dimethylaminoethyl, ß-dibutylaminoethyl, ß-acetylaminoethyl, ß-benzoylaminoethyl, ß-Hydroxypropyl, ß-Hydroxy- # -methoxypropyl, # -Dimethylamino-, # -Diethylamino- or # -dibutylaminopropyl, benzyl, phenylethyl, phenyl, chlorine, bromine, nitro, cyano, Methyl, ethyl, methoxy, ethoxy, hydroxy, dimethylamino, acetylamino or Benzoylaminophenyl.

Compounds of the general formula Ia are of particular industrial importance in which i1 and y1 denote hydrogen, cyano, methyl, ethyl, phenyl or phenyl substituted by chlorine, bromine, cyano, nitro, alkyl or alkoxy and X and Y together denote a tri- or tetramethylene chain.

Of the compounds of the formula I, those are preferred which represent Y carry an electron-attracting radical such as cyano or p-nitro- or cyanophenyl.

To prepare the compounds of the formula I, K -oxo mercaptans of the general formula II XC = OY - C - SH with cyanthioacetamide can be used implement, where X and T have the meanings given.

The reaction of the compounds II with cyanthioacetamide is expedient carried out in the presence of solvents and / or suspending agents, the opposite the reactants are inert and also preferably in the presence of a basic Catalyst.

As a solvent, for. B. alkanols (methanol, ethanol, glycol), Dimethylformamide or dimethyl sulfoxide can be used.

ils basic catalysts can be inorganic, such as Ammonia, Sodium or potassium hydroxide or organic, such as primary, secondary and tertiary Amines, e.g. B. dimethylamine, diethylamine, piperidine, piperidine acetate or triethylamine use. The condensation can also be carried out in glacial acetic acid or without a basic catalyst another organic acid. It succeeds even in the absence of one Solvent by melting the reactants together in the presence of a basic catalyst, for example ammonium acetate or piperidine acetate.

The starting compounds of the formula II are known or can be according to known methods, e.g. B. by reacting the corresponding cC-chloroketones with Sodium hydrogen sulfide.

The implementation of the compounds II with cyanthioacetamide is carried out in detail z. B. so by that one the Cyanthioacetamid and the corresponding i -Ozomercaptan dissolves or suspended and then the base is added dropwise. It is advantageous here that Stir the reaction mixture. As a rule, le mole of cyanthioacetamide is used 0.001-1, preferably 0.05-0.2 mol of base. The implementation proceeds in general exothermic and ended after 0.5 to 4 hours. To complete the reaction is heated moderately if necessary. The work-up is easy because the thiophenthioamides Crystallize during the reaction or on cooling. To the deposition too complete, water is added to the reaction mixture. The so separated Products are then through z. B. separated by suction or centrifugation.

The 2-aminothiophene-3-carboxylic acid thioamides are intermediates for the production of z. B. azo dyes and drugs.

The parts given in the examples are parts by weight. she are related to parts by volume as the kilogram is to the liter.

Example 1 To a slurry of 15.2 parts of dimeric mercaptoacetaldehyde and 20.0 parts of cyanthioacetamide in 80 parts by volume of ethanol are left with stirring 5 parts by volume of piperidine are added dropwise at room temperature. This occurs in an exothermic Reaction increases the temperature to 42 0 and a homogeneous solution is formed, which is stirred at 50,000 for 4 hours. The cooled solution is mixed with 300 parts of water added, 2-aminothiophene-3-carboxylic acid ethioamide separating out.

Raw yield 27.9 parts # 88.4 ß d. Th., M.p. 108-11600.

A sample recrystallized from benzene melts at 120-124 00.

Analysis Ber. C 38.0 H 3.8 N 17.7 S 40.5 Fd. 38.1 4.4 17.5 40.5 Example 2 To a slurry of 36 parts of dimeric mercaptoacetone and 40 parts of cyanthioacetamide 10 parts by volume are left in 150 parts by volume of ethanol at room temperature with stirring Add piperidine dropwise. There is a slight increase in temperature and the greater one Part of the starting products goes into solution.

The mixture is heated to 50 ° C. for 3 hours and then carefully 200 parts by volume of water were added with vigorous stirring and then cooled. The 2-amino-4-methylthiophene-3-carboxylic acid thioamide deposited in the form of yellow needles is suctioned off and dried in vacuo.

Mp 107-111 ° C., yield 41.7 parts o 60.6 s d. Th., Based on Cyanthioacetamide used. A sample recrystallized from benzene melts at 116 - 119 00.

Analysis Ber. C 41.9 H 4.7 N 16.3 Found 42.2 5.0 16.4 example 3 To a mixture of 52 parts of 2-mercaptobutanone- (3) and 50 parts of cyanthioacetamide 15 parts by volume are left in 150 parts by volume of ethanol at room temperature with stirring Piperidine is added dropwise and the reaction mixture is then heated for 4 hours 50.5 parts of 2-amino-4,5-dimethylthiophene-3-carboxylic acid thioamide crystallize on cooling the end.

Mp 133-136 OC; after recrystallization from acetone, mp 135-138 00.

Analysis Ber. C 45.2 H 5.4 N 15.0 Found 45.4 5.7 14.9 Example 4 Aus 47.2 parts of 2-mercaptopentanone- (3), 40 parts of cyanthioacetamide and 12 parts by volume Piperidine in 200 parts by volume of ethanol is obtained analogously to Example 3, 34.8 parts of A 43.5 % analytically pure 2-amino-4-ethyl-5-methyl-thiophene-3-carboxylic acid Bp 126 - 128 00.

Analysis Ber. C 48.0 H 6.0 N 14.0 S 32.0 Found 48.3 6.3 13.7 31.9 Example 5 For the suspension of 13.0 parts of 2-mercaptocyclohexanone and 10.0 parts of cyanthioacetamide 3 parts by volume are left in 50 parts by volume of dimethylformamide at room temperature with stirring Add piperidine dropwise. A moderate increase in temperature occurs and it forms a homogeneous solution. The temperature is kept at 50 ° C. for 3 hours, mixed then carefully with 100 parts by volume of water and cool. The separated 2-amino-4, 5-tetramethylenethiophen-3-carboxylic acid urethioamide is filtered off with suction and with a little cold Methanol washed.

Yield: 17.0 parts (80.2% of theory), melting point 148-154 ° C. One the end Dimethylformamide / water recrystallized sample melts at 154 - 156 ° C.

Analysis Ber. C 50.9 H 5.7 N 13.2 S 30.2 Found 50.9 5.6 13.2 29.8 The compounds characterized in the following table by specifying the substituents X and Y are obtained analogously to the procedure given in the examples. Example X 6 H CH3 7 H C3H7 (i) 8 H C4H9 (n) 9 CH3 C3H7 (n) 10 CH3 O6H5 11 CH3 CH2CH2CN 12 C3H7 (n) C2H5 13 C6H5 H 14 p-C6H4N02 CH3 15 p-C6H4Cl C4H9 (t) 16 C6H5 C6H5 17 CH2OH H 18 CH2CN H 19 CH3 CN 20 CH3 C5H11 (i) 21 CH3 -CH2CH2-OC4 -CH2CH2N (CH3) 2 example XY 23 CH3 -CH2CH2NHCOCH3 24 CH3 CH2-CHOHCH3 25 CH3 -C3H6N (C4H9 26 CH3 CH2C6H5 27 CH3 C2H4C6 28 p-C6H4CN CH3 29 p-C6H4CH3 CH3 30 p-C6H3 32H4 p-C6H4NHCOCH3 CH3 33 CH3 CH3CO 34 CH3 C6H5CO 35 X + Y = - (CH2) 3-36 X + Y = - (CH2)

Claims (3)

Claims l. 2-aminothiophene-3-carboxylic acid thioamides of the general formula in which X and Y, independently of one another, denote hydrogen, cyano, optionally substituted alkyl, aryl or acyl and X and Y together denote a tri-, tetra- or pentamethylene chain. 2. Compounds according to claim 1 of the general formula in which x1 and Y¹ denote hydrogen, cyano, methyl, ethyl, phenyl or phenyl substituted by chlorine, bromine, cyano, alkyl or klkory and X and Y together denote a tri- or tetramethylene chain. 3. A process for the preparation of compounds according to claim 1 or 2, characterized in that # -oxomercaptans of the formula X - C = 0 Y - C - SH reacts with cyanthioacetamide.