Studies on the Constituents of Orchidaceous Plants. VIII. : Constituents of Spiranthes sinensis (PERS.) AMES var. amoena (M. BIEBERSON) HARA. (1). Isolation and Structure Elucidation of Spiranthol-A, Spiranthol-B, and Spirasineol-A, New Isopentenyldihydrophenanthrenes

Abstract

Constituents of Spiranthes sinensis (PERS.) AMES var. amoena (M. BIEBERSON) HARA (Japanese name "nezibana") were examined and several new dihydrophenanthrenes were isolated along with orchinol (1), p-hydroxybenzaldehyde, p-hydroxybenzyl alcohol, hydrocarbons, a sterol mixture, and a ferulate mixture (5). The structures of three new dihydrophenanthrenes, spiranthol-A (2), spiranthol-B (3), and spirasineol-A (4), were determined by spectroscopic methods including two-dimensional nuclear magnetic resonance techniques. These compounds are the first examples of natural dihydrophenanthrenes containing an isopentenyl substituent.