Condensed tannins. 19. Configuration of diol groups in flavan-3,4-diols by paper chromatography and paper ionophoresis

hydride (0-4 ml.) and pyridine (0-4 ml.) gave the diacetate (90 mg.), which crystallizes from ethanol, m.p. 1690 (Found: C, 61-9; H, 5-8; OCH3, 27-6; CO*CH3, 19-6. C23H2809 requires: C, 61-9; H, 5-8; OCH3, 27-8; COCH3, 19-3%). Details of the nuclear-magnetic-resonance spectrum of this compound are listed in Table