Convenient synthesis of drimenol and its oxidation with selenium dioxide

Abstract

A convenient synthesis of drimenol by treatment of readily available drimane 8α,11 diol 11 monoacetate with sulfuric acid in ethanol under mild conditions was developed. Oxidation of drimenol with selenium dioxide gives known drim 7 ene 9α,11 diol and drim 7 ene 11,12 diol as the major products.

Synthesis of 11-aminodrim-7-ene from drimenol

“…Herein we describe the synthesis of 11-aminodrim-7-ene (2) from drimenol (1) (Scheme 1), which we have synthesized earlier [5] from drimandiol 11-monoacetate (5) by treatment with ethanolic H 2 SO 4 (53% yield). Later we developed a twostep synthesis of drimenol (1) from hydroxyacetate 5 consisting of selective elimination of the C 8 -hydroxy group during brief reaction with methanesulfonic acid trimethylsilyl ether (MeSO 3 SiMe 3 ) in CH 3 CN at 18-20°C to form drimenylacetate (6, 70% yield) and subsequent saponification of ester 6 by methanolic KOH into 1 (86% yield).…”

Elimination of C-8-functional groups from driman-8α,11-diol-11-monoacetate and-diacetate

“…, % Ratio of acetates (4)(5)(6), % Yield of hydrocarbon (12), % Driman-8α,11-diol-11monoacetate (7) 7 7 7 7 7…”

“…We previously synthesized drimenol (1) from the monoacetate 7 in one step in greater than 50% yield via treatment with ethanolic H 2 SO 4 [12]. We also dehydrated 7 with POCl 3 in pyridine to produce a mixture of acetates 4-6 in a 46:40:14 ratio [12].…”

“…We also dehydrated 7 with POCl 3 in pyridine to produce a mixture of acetates 4-6 in a 46:40:14 ratio [12]. In continuation of this work, we studied in detail the composition of products from reaction of 7 with trimethylsilylmethanesulfonate MeSO 3 SiMe 3 , trimethylsilyltrifluoromethanesulfonate CF 3 SO 3 SiMe 3 , scandium trifluoromethanesulfonate Sc(CF 3 SO 3 ), PCl 5 , and ion-exchange resin Amberlist-15 and also the products formed from 8 on heating in DMSO in the presence of NaHCO 3 and on boiling in hexane with Merck silica gel.…”

“…The reagent:substrate ratio affected only the reaction rate (2 h or 10 min, respectively). Besides 4, a diene hydrocarbon (12) was also formed (14-17% yield).…”