Philippe Duret

Epimerization of annonaceous acetogenins under basic conditions

Abstract in basic conditions, non-4-hydroxylated annonaeous acetogenins may be epimerized by light basic treatment. The two epimers are inseparable by HPLC, have identical spectroscopic data (MS, IR, UV, 1 H and 13 C NMR). However, specific rotation of the epimeric mixture and enzymatic oxidation after chemical degradation, allow us to characterize this epimerization. In the same reaction conditions, 4-hydroxylated annonaceous acetogenins led to isoacetogenins.

Preparative separation of quinolines by centrifugal partition chromatography with gradient elution

Centrifugal partition chromatography has been successfully applied to the separation of 2-alkylquinolines from liquid combinatorial synthesis crude samples. Original gradient elution using the ternary two-phase solvent systems heptane-water-acetonitrile and heptane-acetonitrile-methanol were used to separate them with high purity degrees. Part of the effluent was monitored with evaporative light scattering detection, for direct control, and the collected fractions were analyzed by thin-layer chromatography, GC, nuclear magnetic resonance spectroscopy and MS. It was thus possible to purify in one run more than 3 g of crude mixture using only 1.31 of solvents to obtain more than 300 mg of several alkylquinolines homologues with 99% purity and in less than 7 h.

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.

Assignment of absolute configuration of the α,β-unsaturated γ-methyl-γ-lactone of the annonaceous acetogenins by a simple enzymatic method

Abstract The absolute configuration of the C-36 or C-34 chiral centers of Annonaceous acetogenins has been determined by simple enzymatic method focusing on the HPLC detection of NADH issued from the enzymatic oxidation of L- or D-lactic acid (obtained by oxidative cleavage of the terminal α,β-unsaturated γ-methyl-γ-lactone) to pyruvic acid by lactate dehydrogenase.

Bulladecin and atemotetrolin, two bis-tetrahydrofuran acetogenins from Annona atemoya seeds

Abstract Two new C 37 tetrahydroxy adjacent bis-tetrahydrofuran acetogenins with a vicinal diol, bulladecin and atemotetrolin, were isolated from the methanol extract of Annona atemoya seeds and characterized by spectroscopic techniques. In addition the known compounds, cherimolin-2 and almunequin, were isolated and identified.

Annonisin, a bis-tetrahydrofuran acetogenin from Annona atemoya seeds

Abstract A new C 35 tetrahydroxy adjacent bis-tetrahydrofuran acetogenin, annonisin, has been isolated from the methanol extract of Annona atemoya seeds and characterized by spectroscopic techniques, in addition to the known compounds, molvizarin, parviflorin, rolliniastatin-1, asimicin, motrilin, cherimolin-1, cherimolin-2, almunequin and annonacin.