SU910628A1 - Process for producing 2-acylominothiazoles - Google Patents

Description

(54) METHOD FOR OBTAINING 2-ACYLAMINOTHIAZOLES

12

The present invention relates to an improved method for the preparation of 2 acylaminothiazeols that find use as bactericidal agents or plant growth regulators.

A known method for producing 2 acylaminothiazoles of the general formula

rm

jJX

in R-C, J.-C

Where

f is alkyl,

which is that 2 aminothiazole is acylated with aliphatic carboxylic acid chloride in acetone in the presence of pyridine 1.

The disadvantage of this method is the use of expensive carboxylic acid halides, the development of which requires additional stages.

Carboxylic acid halides are usually obtained by reacting carboxylic acid with thionyl chloride 21 and, therefore, they are more expensive than carboxylic acids. In addition, according to this method.

2-acylaminothiazlov is not high enough - 60-87%.

The aim of the invention is to reduce the cost of the process and increase the yield of 2-acylaminothiazoles.

The goal is achieved by the fact that when carrying out the process for preparing 2-acipaminothiazoles of the formula

ten

CN,

mgde-alkyl or phenyl,

15 2-aminothiazole is acylated with a carboxylic acid of the general formula)

R-COOH

where R has the indicated values in sulfuric acid in the presence of sulfuric anhydride.

The yield of 2-acylaminothiazoles is 81-97%.

A distinctive feature of the proposed method is that 2-aminothiazole is acylated by carbon

25 acid in sulfuric acid in the presence of sulfuric anhydride.

According to this method, with a mixture of the corresponding carboxylic acid and 2-aminothiazole, oleum (solution of sulfuric anhydride in sulfuric acid) is added at a constant stirring of the appropriate concentration and the reaction is carried out for 10 min at 40-7b ° C, then the reaction mass is cooled to 1525 ° C and poured 25% aqueous ammonia is added to the pH of the acidic aqueous solution of 2-acylaminothiazole sulphate while cooling to pH 8, while 2-acyl-1-thiotiazole precipitates, the mixture is cooled until the precipitate is filtered, washed with cold water to pH 7-7.5 and su al. When 2-aminothiazole is acylated with lower carboxylic acids, it is advisable to carry out the process with more concentrated oleum, since the total amount of oleum per reaction in this case is significantly reduced, the total volume of the reaction mass diluted with water decreases, and the loss of the target product during filtration and washing is reduced. However, when working with concentrated oleum, it is necessary to stir the reaction mixture more intensively in order to avoid local overheating. By acylating 2-aminothiazole with higher carboxylic acids, a high yield of the target products is also achieved when using oleum with a lower concentration of free sulfuric anhydride, since 2-aminothiazoles, which are acylated by higher carboxylic acids, are practically insoluble in an acidic, neutral or alkaline medium . Already 2-capronoylaminothiazole in the form of sulfuric acid salt precipitates upon dilution of the reaction mass with water. The acylation of 2-aminothiazole using the proposed method is carried out with an excess of oleum in such a way that after adding all the oleum, the calculated concentration of sulfuric acid in the reaction mass is not less than 100% . Example 1. 2-Ecenylaminothiazole. to a mixture of 1.5 g (0.025 mol) of acetic acid and 2.0 g (0.02 mol) of 2-aminothiazole, 1.4 ml of 65% oleum (0.022 mol of free sulfuric anhydride) are added with stirring at a rate such that the temperature of the reaction mass was 40-70 ° C. Stir 10 minutes at this temperature, cool to 15-25 ° C and pour it onto 10 g of ice. If the temperature of the reaction mass rises above 30 ° C, then it is cooled or ice is added to it. The cooling acidic solution of 2-acetyl-aminothiaol sulphate is added with cooling to 25% aqueous ammonia to pH 8. The 2-a1-ethyl aminothiols precipitate in an alkaline medium. The mixture is cooled to 0-5 ° C, the precipitate is filtered, washed with cold water (0-5 ° C) to pH 7-7.5 and dried. 2.45 g (86%) of 2-acetylaminothiazole are obtained, m.p. 204205С. Similarly receive: from 1.55 g (0.021 mol) of propionic acid, 1.9 g (0.019 mol.) 2 aminothiazole and 1.4 ml of 65% oleum (0.022 mol of free sulfuric anhydride) 2.7 g (91%) 2-propylaminothiazole, m.p. 157-159С from 2.35 g (0.027 mol) of n-butyric acid, 2.4 g (0.024 mol) of 2-aminothiazole and 1.7 ml of 65% oleum (0.028 mol of free sulfuric anhydride) 3.95 g (96 , 8%) 2-n-butyrylaminothiazole, so pl. 132-134C; from 2.2 g (0.022 mol) of n-valeric acid 1.9 g (0.019 mol) of 2-aminothiazole and 4.5 m of 22% oleum (0.022 mol of free sulfuric anhydride) 3.3 g (94%) 2 n-valerian-aminothiazole, m.p. 101102 ° C of 1.95 g (0.017 mol) of n-caproic acid, 1.5 g (0.015 mol) of 2-aminothiazole and 4.0 ml of 22% oleum (0.02 mol of free sulfuric anhydride) 2.4 g (81%) of 2-n-capronoylaminothiazole, so pl. 96-97 0, from 1.85 g (0.014 mol) of enanthic acid, 1.2 g (0.012 mol) of 2-aminothiazole and 3.0 ml of 22% oleum (0.015 mol of free sulfuric anhydride) 2.2 g ( 86%) 2-n-enantoylaminothiazole, m.p. 92-94 ° C, after recrystallization from ethanol so pl. 95-96C; from 2.45 g (0.017 mol) of n-caprylic acid / 1.6 g (0.016 mol) of 2-aminothiazole and 4.0 ml of 22% oleum (0.02 mol of free sulfuric anhydride) 3.4 g (94 %) 2-n-capryloylaminothiazole, t.cl. 97-100 ° C, after recrystallization from ethanol so pl. 99-101 ° C; e 2.05 g (0.012 mol) of n-capric acid, 1.2 g (0.012 mol) of 2-aminothiazole and 3.0 ml of 22% oleum (0.015 mol of free sulfuric anhydride) 2.9 g of 2-n- caprinoylaminothiazole, m.p. 102-104 With, after recrystallization of their ethanol so pl. 105-106 ° C; from 2fl g (0.01 mol) of n-lauric acid, 1.0 g (0.01 mol) of 2 aminothiazole and 2.5 ml of 22% oleum (0.012 mol of free sulfuric anhydride) 2.3 g (81%) 2-n-laurinoyl aminothiazole, m.p. 108-109, (from ethano.la); from 2.00 g (0.016 mol) of benzoic acid, 1.5 g (0.15 mol) of 2-amino thiaole and 4.0 ml of 22% oleum (0.02 mol of free anhydride) 2.6 g (85% ) 2-benoylaminothiazole, m.p. 149-150s (from ethanol). Example2. To a mixture of 2.1. G (0.016 mol) of n-enanthic acid with 1.5 g (0.015 mol) of 2-aminothiaol, with stirring, 4.0 ml of 22% oleum (0.02 mol of free sulfuric anhydride) at such a rate that the temperature of the reaction mass was in the range of 50-70 ° C. Stir for 10 minutes, cool to 20-25 ° C and pour ice / water at 20 g. It is cooled for 1 hour, the precipitated sulphate of 2-enantoyl sminothiazole is filtered, washed three times with 5 MP of cold water (0-5 ° C), the precipitate is suspended in 20 ml of water, alkalinized with aqueous ammonia to pH 8, filtered, washed with COLD water to pH 7.0-7.5 and get 2.6 g (81%) of 2-n-enantonlaminothiazole, so pl. 94-95p. The application of the proposed method calls for a reduction in the cost of the process and an increase in the yield of 2-acyl-1-utiazoles. . Formula of the invention. A method for producing 2-acylaminothiazoles of the general formula G NH-df where R is Cy, -alkyl or phenyl, by acylation of 2-aminothiazole, o and l. in order to reduce the cost of the process and increase the yield of the target products, the acylation is carried out with a carboxylic acid of the general formula where ft has the indicated values in sulfuric acid in the presence of sulfuric anhydride. Sources of information taken into account in the examination 1..F.Veda, T.Veda, S.Tcyoshima 2-AcyeaminothiazoEes, 3akugaku Zas- shi, 1959, 79, p. 920-924 (prototype). 2. Fizer L., Fizer M. Reagents for organic synthesis, fl. , Mir, 1970, vol. 3, p. 329-330.

Claims (1)

The claims The method of obtaining 2-acylaminothiazole of the General formula Where R-C ^ -C ^ -alkyl or phenyl, by acylation of 2-aminothiaeol, about t and. characterized in that, in order to reduce the cost of the process and increase the yield of target products, acylation is carried out with a carboxylic acid of the general formula RCOOH 15 where ft has the indicated meanings, in sulfuric acid in the presence of sulfuric anhydride.