3,28-Diacetoxylup-20(29)-ene-30-oic Acid and Its ω-Bromoalkyl Esters

Abstract

© 2020, Pleiades Publishing, Ltd. Abstract: A convenient procedure has been developed for the synthesis of3β,28-diacetoxylup-20(29)-en-30-oic acid via oxidation of 3β,28-di-O-acetylbetulin with selenium dioxide in aqueousethanol on heating, followed by oxidation of 3β,28-diacetoxylup-20(29)-en-30-althus formed with sodium chlorite in tert-butyl alcohol. The alkylation of3β,28-diacetoxylup-20(29)-en-30-oic acid with 1,3-dibrompropane and1,5-dibromopentane in boiling acetonitrile in the presence of potassiumcarbonate afforded the corresponding ω-bromoalkyl esters in high yields.