Tobacco Chemistry. 47. (3S,6R,7E,9R)- and (3S*,6R*,7E,9S*)-4,7-Megastigmadiene-3,9-diol. Two New Nor-carotenoids of Greek Tobacco.

Abstract
Two new C13 nor-carotenoids were isolated from Greek Nicotiana tabacum L. and shown by spectroscopic methods and synthesis to be the (3S,6R,7E,9R)- and (3S*,6R*,7E,9S*)-4,7-megastigmadiene-3,9-diols. The sample of 3-oxo-.alpha.-ionol, previously isolated from Greek tobacco, was reinvestigated and contained (6R,7E,9R)-9-hydroxy-4,7-megastigmadien-3-one as the major component and the corresponding, partially racemic (6R,7E,9S)-isomer as the minor component.