Glucosides of 2,5-dihydroxybenzyl alcohol from Homalium longifolium

Abstract

The stems and leaves of Homalium longifolium have yielded eight novel glucosides based on a 2-(β-glucopyranosyloxy)-5-hydroxybenzyl alcohol skeleton. These have been characterized as 2-(β-glucopyranosyloxy)-7-{2-[(2-oxo-2-phenyl)ethyl]benzoyl}-5-hydroxybenzyl alcohol, 2-(6-benzoyl-β-glucopyranosyloxy)-7-[{2-(2-oxo-2-phnenyl)ethyl]benzoyl}-5-hydroxybenzyl alcohol, 2-(2- p-coumaroyl-6-benzoyl- β-glucopyranosyloxy)-5-hydroxybenzyl alcohol, 2-(4,6-dibenzoyl-β-glucopyranosyloxy)-5-hydroxybenzyl alcohol, ( rel)-2-(6-benzoyl- β-glucopyranosyloxy)-7-(1 α,2 α,6 α- trihydroxy-5-oxocyclohex-3-enoyl)-5-hydroxybenzyl alcohol, ( rel)-2-(4,6-dibenzoyl- β-glucopyranosyloxy)-7-(1 α, 2 α, 6 α-trihydroxy-5-oxocyclohex-3-enoyl)-5- hydroxybenzyl alcohol and ( rel)-2-(4,6-dibenzoyl- β-glucopyranosyloxy)-7-(6 α-benzoyloxy-1 α, 2 α-dihydroxy-5-oxocyclohex-3-enoyl)-5- hydroxybenzyl alcohol. All compounds were characterized primarily by extensive use of 2D homonuclear and heteronuclear NMR experiments.