Glycosides from Muscari comosum. 1. Eucosterol glycoside and structure of its methanolysis products

Abstract

A mixture of at least four glycosides has been isolated from bulbs of Muscari comosum. Acidic methanolysis of this mixture afforded a crystalline fraction consisting of four diols 1a differing in the configuration at the epimerizable C-20 and/or C-24 centers. Benzoylation of this diol fraction allowed the isolation of one pure dibenzoate, mp 175–176 °C, to which structure 1b was assigned on the basis of chemical and spectral evidence. This allowed the deduction that one of the aglycone moieties was 27-norlanostane triterpene eucosterol 4a. This conclusion has been confirmed by identification of 4a as the major product of the enzymatic hydrolysis of the glycoside mixture.