The chemistry of the Euphorbiaceae. XV. Further diterpenes from Ricinocarpus stylosus: 1a, 19-diliydroxy-16a-(–)-kauran-17-oic acid

Abstract

Another two diterpenes based on the (-)-kaurane skeleton have been isolated from Ricinocarpus stylosus. One is the known 16,17-dihydroxy-16β-(-)-kauran-19-oic acid (IIb) and the other has been shown to be lα,l9-dihydroxy-16α-(-)-kauran-17-oic acid (IVa). The N.M.R. spectra of various kaurane derivatives in chloroform and benzene solutions are compared.