ESTERIFICATION OF BETULIN 3-ACETATE IN MELTS OF THE MALEIC AND LEVULINIC ACIDS

Abstract

Esters of betulin containing residues of bioactive aromatic and aliphatic acids are of interest to the chemical and pharmaceutical industry as hepatoprotectors, anti-inflammatory, antiulcer and immunomodulatory substances. The development of new efficient, ecological and economical methods for the synthesis of betulin esters is an actual task. A new "green" method for the production of betulin 3-acetate-28-maleate and betulin 3-acetate-28-levulinate has been developed. For the first time, esterification of betulin 3-acetate with melts of maleic acid and levulinic acids was carried out at a temperature of 185-200°C for 5-7 minutes to obtain betulin 3-acetate-28-maleate and betulin 3-acetate-28-levulinate, respectively. The structure of the resulting betulin esters was determined using IR and NMR spectroscopy, and the composition was determined by elemental analysis. The advantage of the developed method for the synthesis of 3-acetate-28-maleate and 3-acetate-28-levulinate of betulin in comparison with the known ones is: the synthesis is carried out in the absence of harmful and hazardous solvents (pyridine, methylene chloride, chloroform), a reduction in the duration of synthesis from 15-40 hours to 5-7 minutes. Maleic anhydride is used instead of maleic anhydride on the preparation of betulin 3-acetate-28-maleate.