Chemistry of the Podocarpaceae. XXVI. Ring-c modification of 12-Hydroxypodocarpa-8,11,13-trien-19-oic acid

Abstract

Methods for the conversion of 12-hydroxypodocarpa-8,11,13-trien-19-oic acid (1) into the α,β-unsaturated ketones (6) and (7) have been investigated. Lithium in liquid ammonia reduction of the ester (19) and the hydroxy acid (24) with concomitant decarboxylation gives moderate yields of the desired products. The ketone (7) has also been prepared in improved yield by a modification of Bible and Burtner's method involving the intermediates (9), (35), (12), (16), (17), and (18).