NO751704L - - Google Patents

Description

Cyclic carbonates and method for their preparation =

The present invention relates to mono-acyloxy (or aro-yloxy) alkylene carbonates of formula

12

in which R and R, which are the same or different, stand for an alkyl, arylalkyl or cycloalkyl radical or hydrogen, R is an alkyl,

arylalkyl, aryl or cycloalkyl radical, as well as a method for producing the aforementioned alkylene carbonates" .

The new compounds are useful intermediates for organic syntheses, such as the production of p-hydroxy amino acids or a,a-,p-triacyloxy (or tri-aroyloxy) derivatives.

The method according to the invention is carried out by reacting compounds of the type

12

wherein R and R have the above meaning; and Y stands. for a . halogen, with alkali metal or alkaline earth metal salts of the acid RCOOH, in which R has the above meaning, in the presence of the acid itself.

The reaction takes place at temperatures between 100 and 200°C and

at such pressures that the liquid phase is maintained.

For further details, reference is made to the following description with embodiments of the invention.

EXAMPLE

ECSIDSiiiLiGS-SY- 1110^ 0^ 61- 0!! 3^®^^^"^ 3^^ 0113^ ^ rzi monochloroethylene carbonate.

9.19 g (75 mmol) of monochlorethylene carbonate, 7.36 g (75 mmol) of anhydrous potassium acetate are added to 100 ml of glacial acetic acid and the mixture is heated under reflux for 15 hours while stirring and protecting against atmospheric moisture. A gas chromatographic sample (standard run with ethylene carbonate) showed a yield of monoacetoxy-ethylene carbonate of 85%. The reaction mixture was cooled to room temperature, the salts were filtered off, the precipitate was washed with ether

and the combined filtrates were concentrated under vacuum on a rotary evaporator to half the volume. About twice the volume of ethyl ether was added to precipitate the residual salts which were filtered off

and washed with ethyl ether. The combined filtrates were then concentrated under vacuum on a rotary evaporator until an oily residue was obtained which was purified by! distillation. Mono-acetoxyethylene carbonate distilled at 132 - 134°C/3 mmHg (172°C bath) leaving a substantial carbonaceous residue in the flask. 5.50 g of the product (thick oil) was obtained by analysis IR spectrum (film), max 1820. (C=0 in carbonate), 1758 (C=0 in acetate), 1230 (C=0 in acetate), 1160, 1090 , 995 cm"<1>(C=0 in carbonate).

For the IR spectrum of cyclic carbonates refer to J.L. Hales et al., J. Chém. Soc, 618 (1957). By n.nur.-analysis (CgDg), & i.55-

(s, 3H, CH3), 3.60 (d, 2H, CH2) and 6.10 p.p.m..(t, 1H, CH).

Claims (4)

1. Mono-acyloxy (or aroyloxy) alkylene carbonates of the general formula 12 o in which R and R are the same or different and stand for an alkyl-, alkylaryl-, aryl^ or cycloalkyl~ radical or hydrogen, and. R is an alkyl, alkylaryl, aryl or cycloalkyl radical <. 2. Process for the production of the mono-acyloxy (or aroyloxy) alkylene carbonates specified in claim 1 characterized by reacting compounds of the type in which R * 1 oQ R <2> has the indicated meaning and Y stands for a halogen, med. alkali metal or alkaline earth metal salts of the acid RCOOH, in which R has the above meaning, in the presence of the acid itself. 3. Procedure as stated in claim 2, characterized by the reaction being carried out .at temperatures from 100 to 2Q0°C. 4. Method as stated in claims 2 and 3, characterized in that the reaction is carried out at such pressures that the liquid phase in the system is maintained.