Two new seco- and di-seco-pregnanes, 2α,3β-dihydroxy-16,17-seco-pregn-17-ene-16-oic acid methyl ester 2β,19-hemiketal (1) and 2,3:16,17-di-seco-pregn-17-ene-3-oic acid-16-oic acid methyl ester-19-hydroxy-2-carboxylic acid-2,19-lactone (2), have been obtained from the trunk bark of Guarea guidonia. Their structures have been established by a combination of 1D- and 2D-NMR spectroscopic techniques and MS data. The unique seco- and di-seco-pregnane carbocyclic skeletal types as found in compounds 1 and 2 are being reported in the Meliaceae for the first time as well as the occurrence of pregnanes in the genus Guarea.
Guarea guidonia; Meliaceae; seco-pregnane; di-seco-pregnane
