SU196797A1 - METHOD FOR OBTAINING COMPLEX ETHERS OF CC-DICHLOR-p-KETO ACIDS - Google Patents

Description

This invention relates to a process for the preparation of precursors for the manufacture of pharmaceuticals, pyrazole dyes, keto acids, etc.

The proposed method for producing halo-substituted analogues of acetoacetic ester - esters of a-dichloro-p-keto acids of the general formula

ABOUT

R-c-cb-cf

where R is alkyl, aryl, R is alkyl, consists in heating cyclic acetals of dichloro ketene of the general formula

Rt

0-С

Rz

С1г-С С

Cs

0-С

R4

where RI, Ra, Rs, Ri is hydrogen, alkyl, with halogen acyls RCOHal (R is alkyl, aryl) at a temperature of 40-150 ° C, followed by separation of the product in a known manner, for example by distillation in vacuum.

The structure of the obtained substances was proved by the data of elementary analysis and splitting reactions, and also confirmed by the data of the X-ray and NMR spectra.

5 The synthesized esters are polyfunctional compounds containing two chlorine atoms in the a-position to the carbonyl and carboxyl groups.

0 Example 1. 15.5 g of dichloromethylene-1,3-dioxolane (m.p. 72-73 ° C at 2 mm Hg. Art. And m. 55.5-56 ° C) and 10 g of acetyl chloride Heat in a sealed tube for 6 hours at 100 ° IO ° C. 19.3 g are discharged under vacuum.

5 (VZO / o) p-chloroethyl ester a-dichloroacetoacetic acid with t. Kip. 83.5 ° C (1.5 mm Hg.

Art.), p 1.4748; df 1.4173; MRn: found 46.36; calculated 46.466.

Found, o / c: C1 45.68, 45.49. 0 Calculated o / o: C1 45.61.

The IR spectrum contains absorption bands in

1162, 1190,

1740, 1760, -v

area V

with about 1240, 1287 SL4-1.

Example 2 18.5 g of acetyl bromide was added to 15.5 g of 2-dichloromethylene-1,3 dioxolane. After a few minutes, the reaction mixture is heated to 45-48 ° C, then it is heated for another 2 hours at 70 ° C. 22.2 g (80 ° / o) of p-bromo ethyl ester are extracted by vacuum distillation.

acids with

m.p. 106- -107 ° С (2 mm Hg / st.}; 1.4940;

df 1.64311; MR D f 1nGaiden 6 49.26, calculated 46.046 ....:

Found, o / o: Ci 25.53, 25.59; Br 28.77, 28.89. SbNtSiOzVg.

Calculated, o / o: C1 25.51; Br 28.75.

1740, 1775, V

IR spectrum: v

s-o

1190, 1200 cf-1.

Example 3. To 5 g of 2-dichloromethylene-1,3-dioxolane was added 4.4 g of benzoyl chloride. The mixture is heated with stirring for 6 hours at 150 ° C. 6.8 g (72 ° / o) of a-dichlorobenzoyl acetic acid p-chloroethyl ester were isolated, with a bale. 149-150 ° С (2 mm of mercury), According to 1.5460; df 1.4115; MRo: found 66.30, calculated 65.91.

Found:: o / o: C1 35.72, 35.87. CcNaEditCalculated, o / j: C1 35.98.

IR spectrum: 1735, 1768, 1053, 1131, 1158, 1187, v 1587 cm-i.

Example 4. 4.6 g of a-dichloroacetoacetic acid p-chloroethyl ester are heated with 30 ml of 209 / aq. NaOH, acidified with HCl and extracted with ether. The presence of dichloroacetic acid and acetic acid and ethylene chlorohydrin was established by the analysis of ethereal par 1162, of the alignment by gas chromatography.

Subject invention

The method of producing esters of a-dichloro-p-keto acids, characterized in that the cyclic acetals of dichloro ketene are heated with halide acyls at a temperature of 40-150 ° C, followed by isolation of the product in a known manner.