SU340159A1 - METHOD OF OBTAINING BENZAMIDES - Google Patents

Description

The invention relates to the field of production of new benzamides which can be used in agriculture.

A known method for producing benzamides of the general formula C — SH — C — C CH (I) where X, X is bromine, chlorine, fluorine, methyl; Rb R2 is methyl. The method consists in the fact that 3,5-disubstituted benzoic acid “whether its reactive derivative is reacted with 3-am, n-3-methyl buty, nome, followed by isolation of the desired product by a known technique. Compounds obtained by a known method have a low biological activity.

O r o

II I II C-NH-C-C-CH2C1 (II)

R2 e X, X is hydrogen, bromine, fluorine, methyl, ethyl, trifluoromethyl, and only one X or X can be hydrogen; R, R2 is methyl, ethyl; Y - hydrogen, bromine, chlorine, fluorine, methyl. The method is based on the aqueous hydrolysis of the hydrochloric salt of oxazoline of the total form. C CHQCJ® 0 /

To accelerate the reaction, such mineral acids can be applied as to hydrochloric, sulfuric, and the process can be carried out at ambient temperature or heated to the boiling point of the reaction mixture.

Prnmer 1. Preparation of yl- (1,1-dimethyl-3chloroacetonyl) -3,5-dichlorobenzamide.

a) Preparation of the hydrochloride salt of 2- (3,5-dichlorophenyl) -4,4-dimethyl-5-chloromethyl-vnoxazoline.

A stream of chlorine is quickly passed through a solution of N- (1,1-dimethylpropinyl) -3,5-dichlorobenzamnd (200 g, 0.782 mol} in ethyl acetate (600 ml) with stirring until it absorbs the theoretical amount of chlorine (55.4 g, 0.78 zolb), measured by a gas meter. The precipitated B solid is filtered off after cooling the reaction mixture and dried. The hydrochloride salt of 2 - (3,5-dichlorophenyl-4,4-dimethyl-5-) is obtained in quantitative yield (254.4 g) chloromethylenoxazoline) with mp 154-157 ° C.

b Preparation of CT (1,1-dimethyl-3-chloroacetonyl) -3,5-dichlorobenzamide.

Hydrochloride salt of 2- (3,5-dichlorophenyl) -4,4-dimethyl-5-chloromethyleneoxazoline (254 g, 0.75 jol) in a mixture of ethanol (1750 ml), water (500 ml) and a solution of concentrated hydrochloric acid (30 d) in water (100 g) is heated on the steam bath for 25 minutes. After adding 500 ml of water, the solution is allowed to cool. The formed needle-like crystals are filtered off and 153.5 g of solid product are obtained. With a m.p. 161 ° C. After recrystallization from aqueous methanol, the product melts at 161 - 163 ° C.

Exit 63%. This product is N- (1,1-dimethyl-3-chloroacetonyl) -3,5-dichlorobenzamide.

Example 2. Getting N- (1,1-Dimethyl3, 3-dichloroacetonyl) -3,5-dichloro | benzamide.

a) Preparation of the hydrochloride salt of 2- (3,5-dichlorophenyl) -4,4-dimethyl-5-chlorodichloromethyloxazoline and its free base.

An excess of chlorine is passed through a solution of N- (1,1-dimethylpropynyl) -3,5 dichlorobenzamide (25.6 g, OD mole in carbon tetrachloride, heated under reflux. After cooling, crystals precipitate out and are obtained in the form solids 34 g of the hydrochloride salt of 2- (3,5-dichlorophenyl) 4, 4-dimethyl-5-chlorodichloromethyloxazoline, yield 85%.

A small sample of this salt is treated in ether with an aqueous solution of sodium carbonate and a free base is obtained. After recrystallization from hexa, the product melts at 94-95 ° C.

Found,%: C 40.5; H 2.6; C1 48.7; N 3.8; About 5.1.

The product is 2- (3,5-dichloro-phenyl) -4,4-dimethyl-5-chloro-5-dichloromethyloxazoline.

b) Preparation of N - (1,1-dimethyl-3,3-dichloroacetonyl) -3,5-dichlorobenzamide.

The hydrochloride salt of 2- (3,5-dichlorophenyl) -4,4-dimethyl - 5-chloro-5-dichloromethyloxazoline (106 g, 0.266 mol) is heated for 30 minutes in ethanol (1500 ml) under reflux in the presence of hydrochloric acids (10 ml} and water (65 ml}. The reaction mixture is then diluted with water (350 ml} and allowed to cool. The filtered solid (65 g) with mp. 155-157 ° C is L- ( 1,1-dimethyl-3,3-dichloroacetone) - 3,5 - dichlorobenzamide, yield 64%.

Example 3. Getting N- (1,1-diethyl-3chloroacetonyl) -3,5-dichlorobenzamide.

a) Preparation of l- (1,1-diethylpropinyl) 3, 5-dichlorobenzamide.

3,5-Dichlorobenzoyl chloride (47 g, 0.225 mol) is reacted with 25 g (0.225 mol} 3-ethyl-3-amnno-ient-1-I | Na (obtained by the method of Hennion and Tychy, L. agn. Chem. Soc., 1953. T. 75, page 1653; bp 114-118 ° C) in the presence of 18 g (0.225 mol} of 50% sodium hydroxide solution. The isolated product is recrystallized from a mixture of benzene and hexane and 42.5 g of a white solid are obtained with a mp of 98-100 ° C.

Found,%: C 59; H 5.3; N 4.9; O 5.8; C1 24.6.

CnnisCUNO.

Calculated,%: C 59.2; H 5.3; N 4.9; O 5.6; C1 24.9.

The yield of M- (1,1-diethyl | ropin.yl) -3,5-dichlorbe .nzamide 69%.

b) Preparation of 2- (3,5-dichlorophenyl) -4,4 diethyl-5-chloromethyleneoxazoline.

A stream of chlorine is quickly passed with stirring through a solution of M- (1,1-diethyl | Pro. Vinyl) -3,5-dichlorobenzamide (14.2 g 0.05 jol) in 300 ml of diethyl ether until it absorbs the theoretical amount of chlorine (3 , 6 g, 0.05 mol}. After stirring for an additional 15 minutes, the solvent is removed and the residue is purified by extraction with pentane. After removing this solvent, 16.9 g of a white oil are obtained, the infrared spectrum of which is combined with the spectrum of exazoline. In this way, 2- (3,5dichlorophenyl) -4,4-diethyl-5-chloromethyleneoxazoline is obtained with lichvenny exit.

c) Preparation of N- (1,1-diethyl-3-chloro-1 acetonyl) -3,5-dichlorobenzamide.

2- (3,5-dichlorophenyl) -4,4-diethyl-5-chloromethyleneoxazoline (12 g, 0.0375 mol) is heated overnight with refluxing in a mixture of 100 ml of ethanol, 40 ml of water and 2 ml of concentrated hydrochloric acid acid. Then 200 ml of water are added and a gummy precipitate is washed with pentalol until the starting material is completely removed. 3.5 g are obtained.

solid matter. t. l. 172.5-17b ° C, which is itself 1M- (1,1-diethyl-3-chloroacetonyl) -3,5-dichlorobenzamide.

Subject invention

Claims (2)

1. A method for producing benzamides of the general formula O r o III II C-NH-C-C-CHjGl R2 X, X is hydrogen, bromine, fluorine, methyl, ethyl, trifluoromethyl, and only X or X can be hydrogen; R R2 is methyl, ethyl; Y is hydrogen, bromine, chlorine, fluorine, methyl, characterized in that the hydrochloride salt of oxazoline of the general formula R -C-R if C CHCJCJ® n / where X, X, Y, R, R are as defined above, is subjected to aqueous hydrolysis in a water-miscible solvent, followed by isolation of the desired product by a known technique. 2. A method according to claim 1, characterized in that the process is carried out in the presence of a mineral acid when heated to the boiling point of the reaction mixture.