GB869458A - New derivatives of l-ascorbic acid - Google Patents

Abstract

The specification comprises 2,5,6 tricarbalcoxy-L-ascorbic acid esters of the formula: <FORM:0869458/IV (b)/1> where R2 is an alkyl group containing from 1 to 3 carbon atoms. Specified esters are 2,5,6 tricarbmethoxy-L-ascorbic acid ester and the corresponding ethoxy and propoxy esters. These esters may be made by esterifying L-ascorbic acid or a salt thereof, or a derivative in which instead of the free OH groups present in the 5 and 6 positions these are replaced by organic or inorganic radicals which are capable of being easily hydrolysed to OH groups, such as the isopropylidene group, with alkyl esters of chloro- or bromocarbonic acid under alkaline conditions. These conditions may be obtained by means of organic tertiary bases such as pyridine, lutidine or collidine. In examples, 2,5,6tricarbethoxy-L-ascorbic acid ester is obtained by adding chlorocarbonic acid ethyl ester dissolved in acetone slowly to ascorbic acid or 5,6 iso-propylidene L-ascorbic acid in pyridine at O to -5 DEG C. and stirring for 2 hours, HCI gas is then added and the oil formed is dissolved in chloroform and shaken out with saturated sodium hydrogen carbonate solution. This solution is acidified with concs HCI and extracted with ether. After removal of the ether the light yellow syrup crystallises. These esters are relatively thermostable and may be used in foodstuffs such as bread.ALSO:2,5,6-Tricarbalkoxy-L-ascorbic acid esters of the formula <FORM:0869458/VI/1> where R2 is an alkyl group containing from 1 to 3 carbon atoms, are used as a source of Vitamin C in foodstuffs, in particular bread, as they lose only 10% of their Vitamin C activity during heat treatment, e.g. baking or sterilization processes. Specified esters are 2,5,6-tricarbmethoxy L-ascorbic acid ester and the corresponding ethoxy and propoxy esters, which esters may be made by the methods described in Group IV (b).