J. L. Lopez

Terpenoids from leaves of Juniperus thurifera

Abstract Nineteen diterpenoids of the labdane, pimarane and abietane skeletons and four known sesquiterpenoids were isolated from Juniperus thurifera leaves. Thirteen of these diterpenoids are described for the first time as natural products. Their structures were elucidated principally by NMR techniques and chemical transformations.

Thuriferic acid. A novel lignan type from juniperus thurifera l

Abstract The isolation and structural determination of a novel type of lignan, thuriferic acid, obtained from the hexane extract of the leaves of Juniperus thurifera L (Cupressaceae) are described. Its structure was confirmed by synthesis and the signals of its 1H and 13C NMR spectra were assigned unequivocally by two-dimensional techniques.

Reaction of SeO2 with dienes: 1. Linalyl acetate

Abstract The reaction of linalyl acetate with SeO2 in alcoholic media affords some selenium containing substances, among the usual allylic oxidation products. The structural determination of products and a proposal for the reaction mechanism are discussed.

Reactions of dienes with selenium dioxide III. Selenolabdanes from methyl 15-O-Acetylisocupressate

Abstract The reaction of methyl 15-O-acctylisocupressate with SeO2/MeOH yielded, in addition to the expected products of allylic oxidation, ≈20% of selenepanes and selenocanes. The formation of cyclic selenium compounds from diolefins in this reaction is similar to that observed from acetyllinalool. The mechanistic proposal through a double electrophilic attack to both double bonds explains the structural variation of the selenium containing products in this and in previous cases.