SU1558897A1 - Method of obtaining diethyl ether of 4-hydroxy-3,5-di-tertbutyl benzyl-n-acetylaminomalonic acid - Google Patents

Abstract

The invention relates to amides of carboxylic acids, in particular to the preparation of 4-hydroxy-3,5-di-tert-butylbenzyl-N-acetylaminomalonic acid diethyl ester, which is used in the production of bioantioxidants. The goal is to increase the yield and improve the quality of the target product. The preparation is carried out by the reaction of N-acetylaminomalonic ester with 4-hydroxy-3,5-di-tert-butylbenzyl-NN-dimethylamine in the presence of an organic acid chloride and a tertiary amine at a molar ratio of 1: 1: 1: 1: 1.1. The process is conducted in an environment of an organic solvent. Exit 98%. M.p. 134-135 ° C. The method allows to increase the yield of the target product by 4-8%, as well as to improve its quality.

Description

The invention relates to organic synthesis, specifically to a process for the preparation of 4-hydroxy-3,5-di-tert-butylbenzyl-H-acetylamino-malonic acid diethyl ester, which is used in the manufacture of bioantioxidants.

The purpose of the invention is to increase the yield and improve the quality of the target product.

The reaction is carried out at 20-60 ° C for 30-60 minutes in the medium of an organic solvent, for example acetone or benzene.

Example 1. To a solution of 2.63 g (0.01 g-mol) of 4-hydroxy-395-di-tert-butylbenzyl-N, N-dimethylamine and 2.17 g (0.01 g-nol) of L-acetylaminomalonic 0,75 ml (0.01 g-mol) of acetyl chloride and 1.57 ml (0.01 g-mol) of triethylamine are added to the ether in 20 ml of acetone. After 60 min (at the reaction temperature

20 ° C) the reaction mixture is treated with 100 ml of water, the precipitate is separated and crystallized from octane. The yield of the target product is 4.2 g (96.5 wt.%, Tgl. 134-135 ° C).

Example 2. To a solution of 2.63 g (0.01 g-mol) of 4-hydroxy-3,5-di-tert-butylbenzyl-I, N-dimethylamine and 2.17 g (0.01 g-mol) of N -acetylaminomalone zethir in 20 ml of acetone was added 1.16 ml (0.01 g-mol) of benzoyl chloride and 1.57 ml (0.01 g-mol) of triethylamine. After 30 minutes (the reaction is carried out at 40 ° C), the reaction mixture is treated with 100 ml of water, and the precipitate is separated and crystallized from octane. The yield of the target product is 4.15 g (95 May.%), So pl. 134-135 ° C.

Example 3. To a solution of 2.63 g (0.0 g-mol) of 4-gndroksn-3,5-di-tert-butyl enzyl-M, M-dimethylamine and 2.17 g (0.01 g-mol) N-acetylaminomalonic

ether in 25 ml of benzene was added 0.75 ml (0.01 gmol) of acetyl chloride and 1.6 ml (0.011 gmol) of triethylamine. The reaction mixture is heated at 60 ° C. 15 min9 is cooled and treated:

100 ml of water, the solvent is distilled off, the residue is crystallized from octane. The yield of the target product is 4.3 g, so pl. 134135 ° C.

one

Example 4. To a cooled to 0 ° C solution of 2.63 g (0.01 gmol) of 4-hydroxy-3,5-di-tert-butylbenzyl-H5Y-dimethylamine and 2.17 g (0.01 g- mol) N-acetylaminomalonic ester in 20 ml of acetone i added 0.75 ml (0901 g-1 mol) of acetyl chloride and then 0.88 ml (0.01 g-mol) of trimethylamine. The mixture is kept at room temperature for 60 minutes and treated with 100 ml of water.

The precipitate formed is separated and crystallized from octane. The yield of the target product is 4.1 g (94 May.%), So pl. 134-135 ° C.

Example 5. To a solution of 2.63 g of 25 (0E01 g-mol) 4-hydroxy-3, 5-di-tert-butylbenzyl-S, N-dimethylamine and 2.17 g (0.01 g-mol) S- acetylaminomalonic ester in 20 ml of acetone, 0.75 ml (0.01 g-mol) of acetyl chloride was added and then a solution of 3.16 g (0.011 g-mol) of tribenzylamine in 10 ml of acetone. Maintain the mixture at room temperature.

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five

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re 60 min The precipitated tribenzylamine hydrochloride precipitate is separated, and the mother liquor is treated with 1% hydrochloric acid. The precipitate is separated and crystallized from octane. Obtain 4.3 g of the target product (98 may.%), So pl. 134-135 ° C.

Thus, the proposed method allows to increase the yield of the target product by 4-8%, as well as to improve its quality.

Claims (1)

Invention Formula A method for preparing 4-hydroxy-3 diethyl ester, 5-di-tert-butylbenzyl-N-acetylaminomalonic acid by reacting the N-acetylaminomalonic ester with 4-hydroxy-3, 5-di-tert-butylbenzyl containing derivative in the presence of a condensing agent and organic the solvent, characterized in that, in order to increase the yield and improve the quality of the target product, 4-hydroxy-3,5-di-tert-butylbenzyl- M, N-dimethyl-amine, as a condensing agent - chlorine The acid of the organic acid and the process are carried out in the presence of a tertiary amine at a molar ratio of 1: 1: 1: 1-1.1.