Tobacco Chemistry. 49. New Labdanic Diterpenoids Isolated from Tobacco.

Abstract
Labdanic compounds (17) were isolated from N. tabacum PB (Bergerac). Of these, 8 are new tobacco constituents and 7, the (12S, 13S)-, (12R, 13R)- and (12R, 13S)-8,13-epoxy-14-labden-12-ols (9, 10, 12), 12,15-epoxy-12,14-labdadien-8-ol (13), the (11E, 13S)- and (11E, 13R)-11,14-labdadiene-8,13-diols (14, 15) and (13E)-15-acetoxy-13-labden-8-ol (17) are new natural products. The isolation of compounds 9, 10 and 12-15, all of which have previously been obtained as products of the reaction of (12Z)- and/or (12E)-abienol with singlet oxygen, strongly corroborates current views on the biogenesis of the tobacco labdanoids.