David Terrero

Nor-sesquiterpenes from Teucrium heterophyllum

A new sesquiterpene, 7-epi-teucrenone, and six novel nor-sesquiterpenes, teuhetone, teuhetenone A, teuhetenone B, tephyllone, 9β-hydroxy-tephyllone and 9-oxo-tephyllone, have been isolated from the aerial parts of Teucrium heterophyllum. This plant also contains the known terpene 3-oxo-α-ionol (3,4-dehydro-blumenol C)

Minor diterpenes from Persea indica: their antifeedant activity

The new diterpenes anhydrocinnzeylanone, garajonone and 2,3-didehydrocinnzeylanone, and the known anhydrocinnzeylanine, have been isolated from Persea indica. The antifeedant activity of these compounds has been evaluated showing the importance of the 11-hemiketal group for the antifeedant effects of ryanodane diterpenes.

A chemotaxonomical study of Sideritis massoniana taxa

Abstract Two varieties of Sideritis massoniana from Madeira (Madeira archipelago) and one from Fuerteventura (Canary Islands) have been examined. Diterpenes, triterpenes, sterols, flavonoids, coumarins and lignans have been isolated. A new coumarin, 7-demethyl-siderin acetate, and the uncommon sterol, 7-oxo-β-sitosterol, have been obtained from S. massoniana var. crassifolia . From the chemosystematic point of view these three taxa of Sideritis belong to one of the groups of the Canarian species of this genus, and should be classified as three different species.

Alkene-γ-lactones and avocadofurans from Persea indica : a revision of the structure of majorenolide and related lactones

Three avocadofurans and an alkene-γ-lactone have been isolated from Persea indica. The data for the lactone are similar to those given for majorenolide to which a δ-lactone structure was previously assigned. We suggest that its structure and those of other analogous lactones, such as majorynolide and majoranolide, should be revised.

Two new sesquiterpenes from Laurus azorica.

The structures of a new eudesmane sesquiterpene, lauradiol, and a new secoeudesmane, azoridione, have been determined by spectroscopic methods. These compounds and the known sesquiterpenic alcohols, clovanediol and caryophyllenol II, have been isolated from the aerial parts of Laurus azorica

Studies on the sesquiterpene lactones from Laurus novocanariensis lead to the clarification of the structures of 1-epi-tatridin B and its epimer tatridin B

The germacranolide 1-epi-tatridin B has been isolated from the aerial parts of Laurus novocanariensis. We have observed that the identification of this lactone and its epimer tetradin B in the scientific literature is confusing and contradictory. We have therefore studied this issue clarifying errors and contributing to the structural elucidation of other related products. Moreover, we have isolated from this plant a lactone with an 1,5-ether bridge, previously obtained from Austrolabium candidum. We have now named it austroliolide, reassigned its 13C NMR spectrum and compared its structure with that of badgerin. In addition, we have also isolated from L. novocanariensis the known germacranolides artemorin, costunolide, tatridin A, tulirinol and verlotorin, the eudesmanolides β-cyclopyrethrosin, 1β-hydroxy-arbusculin A, magnoliaolide and reynosin, and the guaianolide dehydrocostus lactone.

Vol. 68, 2003 An Effective One-Pot Synthesis of 5-Substituted Tetronic Acids.

An expeditious one-pot synthesis of 5-substituted tetronic acids from aldehydes and terminal conjugated alkyne as starting materials is described. The entire process embodies two consecutive chemical events: a catalytic domino reaction to build the 1,3-dioxolane scaffolds 5 and a two-step acid-catalyzed trans-acetalization-lactonization reaction to furnish the tetronic acid derivatives 6.