Chemistry of the Podocarpaceae. XXIX. The preparation of 6-oxygenated derivatives of Abieta-8,11,13-trien-18-oic acid

Abstract

    Peracid oxidation of the enol acetate (23) derived from the C 7 ketone (6) provides a method for introducing an oxygenated substituent into the C 6 position of abieta-8,11,13-trien-18-oic acid (1). Reduction of the keto acetate (10) with sodium borohydride and hydrogenolysis of the C 7 hydroxy group of the hydroxy acetate (28) affords the 6-acetate (33) in 55% overall yield from methyl abieta- 8,11,13-trien-18-oate (2). Hydrolysis of the acetoxy ester (33) followed by re-methylation of the C 4 carboxy group and oxidation of the hydroxy ester (34) gives the C 6 ketone (35).