Synthesis of N-containing drimane sesquiterpenoids from 11-dihomodriman-8α-ol-12-one

Abstract

Beckmann reaction products of 11-dihomodriman-8α-ol-12-one oxime with Ac2O in pyridine, 86% H3PO4, p-TsCl in pyridine, and PCl5 in ether were investigated. It has been found that the major product from treatment of the oxime with Ac2O is the oxime acetate. Reaction of the oxime with 86% H3PO4 gave (1S,2S,4aS,8aS)-2,5,5,8a-tetramethyldecahydro-1H-naphtho[1, 2][5, 6]-3-methyl-4,5-dihydro[1, 2, 6]oxazine; with p-TsCl, (1S,2S,4aS,8aS)-2,5,5,8a-tetramethyldecahydro-1H-naphtho[1, 2][5, 6]-2-methyl-4,5dihydro[1, 3, 6]oxazine; with PCl5, a mixture of products containing 11-acetylamino- and 11-methylaminooxodrimenes that were isomeric at the double bond, norambreinolide, and a 1,3,6-oxazine.