Tannins and Related Compounds. XCVI. : Structures of Macaranins and Macarinins, New Hydrolyzable Tannins Possessing Macaranoyl and Tergalloy Ester Groups, from the Leaves of Macaranga sinensis (BAILL.) MUELL.-ARG.

Abstract

Together with eleven known compounds (1-11), seven new tannins, 3-desgalloylterchebin (12), macaranins A, B and C, and macarinins A, B and C, have been isolated from the leaves of Macaranga sinensis (BAILL.) MUELL.-ARG. (Euphorbiaceae). Macaranins A (14), B (13) and C (17) have been determined on the basis of chemical and spectroscopic evidence to be hydrolyzable tannins possessing a novel acyl group (macaranoly group) at the 3, 6-positions of the ¹C₄ (or skew boat) β-D-glucopyranose ring, while macarinins A (18), B (15) and (16) were characterized as those having a tergalloyl group at the same positions.