Veronica Armstrong

SYNTHESIS AND ANTITUMOR ACTIVITY OF PUUPEHEDIONE AND RELATED COMPOUNDS

Abstract The first enantiospecific synthesis of bioactive marine puupehedione ( 2 ) and related compounds from (−)-sclareol ( 11 ) is reported. The antitumor activity of these compounds was assayed and compared with that of the natural products.

Synthesis of 3-Carboxycoumarins from O-Methoxybenzylidene Meldrum's Acid Derivatives

Abstract Reaction of o-methoxybenzaldehydes with Meldrums acid followed by cyclization in sulfuric acid of the benzylidene derivatives 3a-g affords 3-carboxycoumarins in excellent yields.

Antifeedant Activity of Some Polygodial Derivatives

Polygodial (1) and its derivatives acetal 2 (propylene) and 3 (ethylene) were prepared and their antifeedant activity and toxic effects evaluated on several insect species with different feeding ecologies (Spodoptera littoralis, Leptinotarsa decemlineata, Myzus persicae and Rhopalosiphum padi) along with that of polygonone (4). We also tested their selective cytotoxic effects on insect-derived (Spodoptera frugiperda ovarian Sf9 cells) and mammalian Chinese hamster ovary (CHO) cells. The antifeedant activity of these compounds was consistent with the proposed mode of action for antifeedant drimanes, i. e. adduct formation with amino groups for M. persicae and R. padi (dialdehyde > ketoaldehyde > aldehydeacetal). This was not the case for L. decemlineata, and the cytotoxic effects on insect-derived Sf9 and mammalian CHO cells (aldehydeacetal > dialdehyde > ketoaldehyde).

Formal Synthesis of Ambrox® and 9-Epiambrox

Abstract (-)-Drimenol (5) was used as starting material for the synthesis of diastereoisomeric diols 3 and 4, through the nitrile 7, Compounds 3 and 4 are the direct precursors of Ambrox® (1) and 9-epiambrox (2).

Synthesis of racemic and chiral albicanol, albicanyl acetate and cyclozonarone: cytotoxic activity of ent-cyclozonarone

The total synthesis of racemic cyclozonarone ((±)-3) was achieved from E,E-farnesol (4) in an eight-step sequence in 6.6% overall yield. Albicanol ((±)-1) and its acetate ((±)-2) are intermediates. A similar sequence starting from natural (-)-drimenol (5) gave (+)-albicanol (1) and (+)-cyclozonarone (3) (42% and 11% yield, respectively). The cytotoxic activity of (+)-cyclozonarone was assayed and showed some selectivity towards MS-1 (mice endothelial cells).

New cyclic acetals related to Ambergris and their olfactory evaluation

Hemisyntheses of cyclic acetals (11–18) were performed using (–)-polygodial and (+)-confertifolin as chiral starting materials. The acetals obtained were evaluated for their odoriferous properties.

A Revision of the Absolute Configuration of Drim-9(11)-en-8α-ol

Abstract A new synthesis of the drimane sesquiterpene 1has been performed using (-)drimenol (3)as chiral starting material. Comparison of the specific rotation of the natural and synthetic 1established the absolute configuration of the naturally occurring 1as the normal drimane skeleton.

Configuration and Leishmanicidal Activity of (−)-Argentilactone Epoxides

Epoxidation of argentilactone (1) with m-chloroperbenzoic acid gave a diasteromeric mixture of 2 and 3 in a ratio 1.8 : 1, with total yield 60%. The configuration of 7,8-oxirane ring for both diasteromers was determined by NMR analysis. Reaction of 1 with urea hydrogen peroxide gave the 3,4-epoxide (4) in 65% yield. The in vitro activity of 2, 3, 4 and argentilactone against Leishmania amazonensis was tested, only epoxides (2) and (3) showed leishmanicidal effect.