Phenanthrenes of Eulophia nuda

Abstract

From the tubers of Eulophia nuda six phenanthrene derivatives have been isolated: 9,10-dihydro-2,5-dimethoxyphenanthrene-1,7-diol, 9,10-dihydro-4-methoxyphenanthrene-2,7-diol, 1,5-dimethoxyphenanthrene-2,7-diol, 1,5,7,-trimethoxyphenanthrene-2,6-diol, 5,7-dimethoxyphenanthrene-2,6-diol and 4,4′,8,8′-tetramethoxy [1,1′-biphenanthrene]-2,2′,7,7′-tetrol. 4-Hydroxybenzaldehyde and 4-hydroxybenzyl alcohol were also isolated. The structures were assigned by spectroscopic methods and the structure of 9, 10-dihydro-2,5-dimethoxyphenanthrene- 1,7-diol was also determined by a single-crystal X-ray structure analysis of its acetate derivative. © 1988.