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B Figadère

Publications and source records attributed to B Figadère.

8 recordsLinked to original sources
PubMed2000

Highly Enantioselective Aldol Reaction with 2-Trimethylsilyloxyfuran: The First Catalytic Asymmetric Autoinductive Aldol Reaction The authors wish to thank J. C. Jullian for his help in NMR experiments, Dr. X. Franck for stimulating discussions, and Prof. R. Hocquemiller for his continuous interest in this study. Thanks are due to M.J. Vega Capela for the experiments with heptadecanal. L. Tache and B. Mbeninack are acknowledged for the preparation of the (R,R)-2 isomer.

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Journal Article↗
PubMed2000

Synthesis, spectroscopy, and cytotoxicity of glycosylated acetogenin derivatives as promising molecules for cancer therapy.

Several glycosyl derivatives of squamocin (1) have been synthesized by glycosylation under Lewis acid catalysis with two different 1-O-acetyl sugars. Separation of these compounds has been achieved by HPLC and centrifugal partition chromatography (CPC). A detailed NMR, ESIMS, and LSIMS study allowed complete structural elucidations. The cytotoxic activity of the glycosyl derivatives was investigated and compared with that of squamocin and dihydrosquamocin against human epidermoid carcinoma cells (KB), African green monkey (Cercopithecus aethiops) kidney epithelial cells (VERO), and mouse lymphocytic leukemia cells (L1210). The antiproliferative effects of some derivatives were studied on cell cycles in mouse lymphocytic leukemia cells (L1210).

Animals↗
PubMed1999

Semisynthesis and cytotoxicity of amino acetogenins and derivatives.

Semisynthetic derivatives were prepared from two natural annonaceous acetogenins, rolliniastatin-1 and squamocin, and their cytotoxicity was evaluated. Amino derivatives show decreased bioactivity. Isorolliniastatin-1 was found to be much less toxic than rolliniastatin-1 after intraperitoneal administration to mice, although the in vitro cytotoxicity of both compounds was comparable.

Animals↗
PubMed1998

Enantiospecific semisynthesis of (+)-almuheptolide-A, a novel natural heptolide inhibitor of the mammalian mitochondrial respiratory chain.

The development of novel styryl lactone derivatives as bioactive compounds and the semisynthesis of both 4,5-dialkoxylated eight-membered-ring lactones with a heptolide skeleton (almuheptolide-A (1) type) and 7-alkoxylated delta-lactones with a saturated furanopyrone skeleton (etharvensin (8) type) have been successfully achieved from the chiral unsaturated alpha-pyrone altholactone (7). This new method is a direct and one-step enantiospecific alkoxylation of altholactone (7) in concentrated acid medium, followed by formation of the eight-membered-ring zeta-lactone. The reaction mechanism operating in the synthesis of the heptolide skeleton is postulated to be a direct Michael-type addition. Concerted opening of both the alpha-pyrone and tetrahydrofuran rings and subsequent intramolecular rearrangement with the ring closure lead to almuheptolide-A (1). This compound (1) and its diacetated derivative (1a) showed potent and selective inhibitory activity toward mammalian mitochondrial respiratory chain complex I. This mechanism of action, reported here for the first time, provides a possible explanation for the cytotoxic and antitumor activities previously described for related natural compounds.

Animals↗
PubMed1998

Three new bistetrahydrofuran acetogenins from the seeds of Annona spinescens.

Three new bistetrahydrofuran acetogenins, carolins A-C (1-3), were isolated from the MeOH extract of Annona spinescens in addition to the known compound, squamocin (4). The structures of 1, 2, and 3 were elucidated by spectroscopic methods including LSIMS/MS technique and confirmed by a chemical transformation, The cytotoxic activity of the new compounds 1-3 is reported and discussed in comparison with 4 and the previously isolated spinencin (5).

4-Butyrolactone↗
PubMed1991

Arocalciferols: synthesis and biological evaluation of aromatic side-chain analogues of 1 alpha,25-dihydroxyvitamin D3(1a).

Aromatic side-chain analogues (arocalciferols 6-9) of the steroid hormone 1 alpha,25-dihydroxyvitamin D3 (1) were synthesized and biologically evaluated. The analogues were prepared by coupling the vitamin D A-ring enyne 14 with the appropriate enol triflate of a modified CD steroid fragment of the type 22. The resulting dienyne 23 was then transformed in three steps to the vitamin D analogues 6-9. Biological evaluation of these analogues have provided information concerning side-chain topographical effects on in vivo and in vitro activity.

Animals↗