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.

Synthesis and in vitro trypanocide activity of several polycyclic drimane-quinone derivatives.

The Diels-Alder reaction between two polygodial-derived dienes and simple quinones to yield substituted naphtho- and anthraquinones, is described. The in vitro trypanocide activity for the series was determined. Two of the new compounds showed an activity ten and two times higher, respectively, than nifurtimox and benznidazole, the medicines of choice for the treatment of the acute Chagas' disease.

Synthesis and antiprotozoal activity of naphthofuranquinones and naphthothiophenequinones containing a fused thiazole ring.

The synthesis of tetracyclic quinones 10a,b, 14a,b, 19a,b and 20a,b is described. The preparations involve regioselective Diels-Alder reactions via trapping the thiazole o-quinodimethane 9 with several benzofuranquinones and benzothiophenequinones. The structure of the regioisomers was assigned through 2D NMR 1H-13C HMBC experiments performed on 10a and 14a.