Tannins and Related Compounds. XXIX. Seven New Methyl Derivatives of Flavan-3-ols and a l,3-Diarylpropan-2-ol from Cinnamomum cassia, C. obtusifolium and Lindera umbellata var. membranacea

Abstract

Seven new methyl derivatives of flavan-3-ols (compounds 1—7) and one l,3-diarylpropan-2-ol (compound 8) were isolated from three Lauraceous plants (1, and 3—7 from Cinnamomum cassia, 1, 3 and 4 from Cinnamomum obtusifolium, and 1—4 and 8 from Lindera umbellata var. membranacea). Their structures were characterized mainly by proton nuclear magnetic resonance (H-NMR) examination combined with nuclear Overhauser effect (NOE) experiments as the 3’-O-methylate (1), 3 ’,4’-di-O-methylate (2), 5,3’-di-O-methylate (3) and 5,7,3’-tri-O-methylate (4) of (-)-epicatechin, the 4’-O-methylate (5), 7,4’-di-O-methylate (6) and 5,7,4’-tri-O-methylate (7) of (+)-catechin, and l-(4’,6’-dihydroxy-2’-methoxyphenyl)-3-(4’’-hydroxy-3’’-methoxyphenyl)-propan-2-ol (8). © 1985, The Pharmaceutical Society of Japan. All rights reserved.