Über die Konstitution von Loroglossin. Vorläufige Mitteilung

The Constitution of Loroglossine. Loroglossine, a characteristic constituent of orchids, is shown to be bis‐[4‐(β‐ D ‐glucopyranosyloxy)‐benzyl]‐(2 R , 3 S )‐2‐isobutyl‐tartrate ( 1 ). Hydrolysis and esterification gave 1 mol‐equiv. of dimethyl (+)‐2‐isobutyl‐ erythro ‐tartrate ((+)‐3) and 2 mol.‐equiv. of a glucoside which, after acetylation, gave 4 , identical with a synthetic sample. The erythro configuration of (+)‐ 3 by oxidation of isobutyl‐maleic acid with osmium tetroxide and subsequent esterification. The absolute configuration of (+)‐ 3 was based on Horeau experiments and NMR. data of the diastereomeric mixture of its esters 7 and 8 with S (+)‐ and R (−)‐α‐phenylbutyric acid respectively.