Isolation, structure, and synthesis of a stilbene glucoside from the bark of: Picea glauca (moench) voss.

Abstract

The fractionation of phlobaphenes from white spruce bark by column chromatography gave the non-crystalline stilbene glucoside trans 3,4′5-trihydroxy-3′-methoxystilbene-3-O-β-D-glucopyranoside (1). Purification was achieved through deacetylation of its hexaacetate (2). Compound 1 was cleaved with emulsin or dilute acid to the aglycone 4, and D-glucose. The acetate, benzoate, and dihydro-derivatives of 1, and the acetate, benzoate, methyl ether, and dihydro-derivatives of 4 were prepared. Oxidation of the benzoate derivative of 1 with chromic acid gave dibenzoyl-α-resorcylic acid. Similar oxidation of 2 gave acetylvanillic acid together with an uncharacterized acid which was hydrolyzed to D-glucose and β-resorcylic acid. The structure of 1 was therefore as shown, and its derivative 2 was synthesized. Vanillin was condensed with 3,5-dihydroxyphenylacetic acid and the product was decarboxylated and deacetylated. This compound was condensed with tetra-O-acetyl-α-D-glucopyranosyl bromide to yield a mixture of products which, after acetylation, were separated, using preparative thin-layer chromatography, to give the desired 2.