R. Z. Andriamialisoa

A new class of antitumor compounds: 5'-nor and 5',6'-seco derivatives of vinblastine-type alkaloids.

isopropylpenty1)triphenylphosphonium bromide, 71436-81-2; (3tetrahydropyranyloxypropy1)triphenylphosphonium bromide, 70665-02-0; isohexyltriphenylphosphonium bromide, 70240-41-4; (methoxymethy1)tripheriylphosphonium chloride, 4009-98-7; (3tetrahydropyranyloxyprolpylidene) triphenylphosphorane, 71436-82-3; [ 3(2-methyl-1,3-dioxolain-2-yl)propylidene] triphenylphosphorane, 3054-93-1; (4-methylpentylidene)triphenylphosphorane, 54517-55-4; 3-methylbutylidenetriphenylphosphorane, 39110-24-2; methoxyJ . Org. Chem., Vol. 44, .No. 22, 1979 3765

Diastereoselective synthesis of (2S,3R) 2-carboxy-3-pyrrolidine acetic acid, a simple kainic acid analogue

Abstract (25,3R) 2-carboxy-3-pyrrolidine acetic acid was synthetized from (S)-pyroglutamic acid by a route involving the conjugate addition of t-butyl-2- lithiophenylthioacetate to N-methoxycarbonyl α, β-unsaturated lactam.

α-Hydroxylation of β-dicarbonyl compounds

Abstract Various β-dicarbonyl compounds can be hydroxylated as their silyl enol ethers by m -chloroperbenzoic acid (MCPBA).

New approaches to the synthesis of eburnane alkaloids

Abstract Aldehyde 12 which is a key precursor of the Eburnane alkaloid vincamine 1 has been prepared in two ways. The first one involves a photochemical rearrangement of a spiro oxaziridine intermediate and the second is based on an imino Diels-Alder reaction followed by a stereo and regioselective alkylation.

Structure de la catharinine: “alcaloïde” bis-indolique isolé de plusieurs espèces de catharanthus

Abstract Structure 3a proposed for catharinine is confirmed by X-ray study of one derivative.

Synthèse des néothramycines

Resume The antibiotic antitumour neothramycins 1 and their analogues 3 were synthetized through regioselective partial reduction of the acyclic imides 15 and 7 leading to the carbinolamides 16 and 10 . Simultaneous reduction and deprotection of the intermediates 18 afforded the title compounds.

Alcaloïdes mono-indoliques de Catharanthus ovalis

Abstract Twenty four monoindolic alkaloids have been isolated and identified from aerial parts of Catharanthus ovalis . Twelve of them had not previously been isolated from a Catharanthus species.

Rearrangement du squelette de la catharanthine

Resume Catharanthine N -oxide 1 leads through a [2,3]-sigmatropic rearrangement to 2 whose structure is established by chemical studies and confirmed by X-ray analysis.

Plantes malgaches—XVIII : Nouvel alcaloïde de Catharanthus ovalis Mgf. (apocynacées). La cathovalinine ou époxy-14α,15α hydroxy-19S tabersonine

Resume Structure 1a has been established for cathovalinine, a minor alkaloid isolated from Catharanthus ovalis Mgf. Its relative configuration follows from X-ray analysis.

Étude de la vindolinine—III: Hémisynthèse de l'andranginine

Abstract Thermolysis of Δ18-tabersonine 3 in methanol solution affords, (±)andranginine 5, (±) epi-andranginine 9a and optically active 6.