Chemistry of the Podocarpaceae. XXVII. Ring-c modifications of methyl abieta-8,11,13-trien-18-oate

Abstract

Functionalization of the isopropyl group of methyl abieta-8,11,13- trien-18-oate (8) has been achieved by intramolecular cyclizations of the 12-carboxy derivative (10) with lead tetraacetate and by thermolysis of the diazomethyl ketone (11). ��� Nitration of methyl 12-acetylabieta-8,11,13-trien-18-oate (9) has given the products (21) and (30), arising from nitrodeacylation and nitrodealkylation reactions, respectively. The nitro ketone (30) has been converted into methyl 13-hydroxypodocarpa-8,11,13-trien-18-oate (38) in 26% overall yield from the ester (8). Birch reduction of the methyl ether of the phenol (38) afforded the enone (50), a potentially useful intermediate for synthesis.