Françoise Khuong-Huu

Oxydation photochimique D'amines tertiaires et D'alcaloïdes—VIII: Oxydation photochimique d'alcaloïdes indolinoindolizidiniques, vincadifformine, tabersonine, n(a)-acétyl dihydro-2,16 vincadifformine et n(a)-acétyl dihydro-2,16 tabersonine

Abstract Dye-sensitised photoxidation of the N b -nitrogen of indolino- indolizidine alkaloids, vincadifformine, tabersonine and their N a -acetyl-2-16-dihydro derivatives has been studied to determine the influence of structural factors on the site of oxidation.

Studies related to the synthesis of maytansinoids.

Two approaches to the partial synthesis of C1–C5 of a bis-nor maytansinoid 1 have been investigated starting on the one hand with (S)-(−)-malic acid and on the other, with D-(+)-ribonolactone.

New rearranged limonoids from Harrisonia perforata. III.

Three new limonoids, named haperforins C2 (1), F (2), and G (3), were isolated from a sample of Harrisonia perforata leaves collected in Central Vietnam. Their structures were determined by single-crystal X-ray diffraction analyses, and their NMR and mass spectral data are reported.

The opening of trans-2-3-epoxy-1-butanol derivatives with organometallic reagents

Abstract The opening of trans -2-3-epoxy-butan-1-ol derivatives with various organometallic reagents was studied to find the best conditions necessary to obtain convenient yields and regioselectivities for their application in natural product synthesis.

Structure of koumine, an alkaloid from gelsemium elegans benth

The structure of koumine, an indole alkaloid from Gelsemium elegans Benth., was determined by a X-ray crystallographic study.

Alchornéine, isoalchornéine et alchornéinone, produits isolés de l'Alchornea floribunda Muell. Arg.

Resume Structures of alchorneine, imidazo-(1–2a) pyrimidine derivative, of isoalchorneine. imidazo-(1–2a)-imidazole derivative, and of alchorneinone have been determined by physical methods and chemical correlations. Synthesis of isopropyl-4 imidazolidone-2 (S) leads to the determination of the absolute configurations of these products.

Studies toward the total synthesis of polyoxygenated labdanes: preliminary approaches

Abstract Using the keto-ester 3 as a starting material, methods are developed for the successive introduction of hydroxy groups at C-6, C-7 and C-8 of a decalin system, as well as for elaboration of a C-9 pentadiene chain in a preliminary approach to the total synthesis of trihydroxylabdadienes.

Indole alkaloids from Hunteria zeylanica

Abstract Fourteen indole alkaloids were isolated and identified from the leaves and bark of Hunteria zeylanica : isocorymine, vobasine, (+)-eburnamenine, eburnamine, isoeburnamine, O -ethyleburnamine, O -methyleburnamine, O -methylisoeburnamine, pleiocarpamine, dihydrocorynantheol, yohimbol, epiyohimbol, tuboxenine and hydroxy-17-decarbomethoxy-16-dihydroepiajmalicine. O -Ethyleburnamine, O -methylisoeburnamine, epiyobimbol and hydroxy-17-decarbomethoxy-16-dihydroepiajmalicine, although known products, were isolated for the first time from a natural source.

From disubstituted acetylenes to trisubstituted olefins. An application

Abstract The transformation of disubstituted acetylenes to trisubstituted olefins was studied in order to obtain precursors of the north-eastern part of maytansine. Depending on the starting material, a trans or a cis stannylation reaction could lead to the olefin of the desired stereochemistry

Oxydation photochimique d'amines tertiaires et d'alcaloïdes—X : Introduction d'un groupement fonctionnel en α de l'azote nb de la yohimbine par oxydation photosensibilisee

Dye-sensitized photooxidation of the imino-ether 5, prepared from yohimbine 1a, led to the α-amino nitrile 9a when the reaction was performed in the presence of oxygen and KCN. Derivative 9a was hydrolyzed to the amide 9b, the transformation of which to carboxamido-5β-yohimbine 15 was studied.