CA1051911A - Process for the preparation of epoxydes of organic enolesters - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

The invention relates to a process for the preparation of epoxides of organic enolesters having the general formula:

wherein R is an allyl radical, which process comprises reacting salts of organic acids of alkaline or alkaline-earth materials of formula Me(OOCR)n wherein Me is the alkaline or alkaline-earth metal, n represents the valence and R has the nbove meaning, with compounds of the general formula:

Description

105191~
The present invention re~ers to a process for the preparation of epoxides of enolesters with the general formula:

\ / \ OCOR
H / C ~ C H

wherein R is an allyl radical, which process comprises reacting salts of organic acids of alkaline or alkaline-earth materials with compounds of formula ,/ \ X

\ C/ \C /
H / \ H

wherein X represents an halogen, the reaction taking place in the presence of a solvent selected among alcohols, ketones, dimethylformamide and alkyl acetates, at a temperature ranging between -30 and ~70C and at such a pressure so as to maintain the system in a liquid phase.
The reaction pàttern is as follows .
H \ / O ~ X . . H \ O O~OR~
n C - C + Ite(OOCR~n - ~ n ~C ----- C
H H . H H

~e~ ~

wherein Me is the alkaline or alkaline-earth metal, n represents the valence, and R has the above meaning. The reaction is carried out in a solvent medium, which must be selected case B

~051911 by case, to obtain maximum yields, ~ecause it must dissolve, at least partially, also the organic acid salt, and also be as inert as possib~e to the starting epoxide and to the desired reaction product, but at the same time sufficiently polar to favour said reaction. Solvents which may be used advantageously are methanol, ethanol, isopropanol, n-butanol, acetone, dimethyl-formamide, and ethyl acetate. Concerning more detailed operating procedures we refer to the following example, which is by no means intended to limit the scope of the invention itself. The compounds obtainable with the process of the invention are useful intermediates for organic syntheses, in the preparation, for example of alpha-hydroxy, -acyloxy, -amino carbonyl or, as described in Canadian patent application 224,347 filed on April 10, 1975 in the name of the same applicant, of beta-hydroxy-aminoacids.
EXAMPLE
Prepa_ation of vinyl-acetate-epoxyde from monochloroethylenoxide 1.55 g (19.8 mmoles) of monochloroethylenoxide were added in a 5 minutes interval to a suspension of 1.95 g (23.8 mmoles) of sodium vinyl acetate anhydrous in 15 ml absolute ethanol, stirred, cooled to 5C and protected from the atmospheric moisture.
The mixture was kept at this temperature and under stirring for 20 hours in a closed vessel, 20 ml of methylene chloride were added and stirringwas continued for a few more minutes at 5C.
The suspension was filtered cool (5C) to separate the salts, which were washed with a few cc of methylene chloride. A gas ;~
chromatography analysis (through a calibration curve) of the collected filtrates showed a yield in vinylacetateepoxyde (in respect of monochloroethylenoxide) of 80%. From the collected filtrates ethanol, methylene chloride, and secondary low boiling products were removed through a fractionated distillation at about 20 mm Hg with a temperature of the water bath of 15C in & ~

~05191~
flask equipped with Liebig cooler (column about 10 x 0,8 cm) with water circulation at 10C, filled with Raschig rings and connected to a liquid air cooled trap. In such a way a partial re-flux was obtained, which ensured a reasonable fractionation.
At the end of the distillation, to further remove the impurities, the cooler was removed and the bottom residue was distilled at about 50 mm Hg in a water bath at 20C. By stopping this last operation when the bottom residue was epoxy vinylacetate at about 90% (the residue consisting of a secondary higher boiling product), 1.47 g of product were obtained, corresponding to a yield of about 65% in pure epoxy vinyl acetate.
The epoxy may be further purified by distillation through a "spinning band", boiling point 35 - 40C at 5 mm Hg.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A process for the preparation of epoxides of organic enolesters having the general formula:

wherein R is an allyl radical, which process comprises reacting salts of organic acids of alkaline or alkaline-earth materials of formula Me(OOCR)n wherein Me is the alkaline or alkaline-earth metal, n represents the valence and R has the above meaning, with compounds of the general formula:

wherein X represents an halogen, the reaction taking place in the presence of a solvent selected among alcohols, ketones, dimethylformamide and alkyl acetates, at a temperature ranging between -30 and +70°C and at such a pressure so as to maintain the system in a liquid phase.