Nicole Langlois

Application of a modification of the Polonovski reaction to the synthesis of vinblastine-type alkaloids.

Eine neue C-16/C-2 l-Fragmentierungvon Ibogan-Derivaten wie (I) oder (VI), induziert durch eine modifizierte Polonovski- Reaktion, fuhrt in Gegenwart von Aspidosperman-Derivaten wie (II) (Vindolin) zu Verbindungen vom Vinblastin-Typ mit naturlicher [(S)-] Konfiguration an C-16 [notwendig fur eine signifikante Antitumor-Aktivitat ], z.B. (IVa) (Anhydro-vinblastin) bzw. (VIIa) [daneben werden die Epimeren (IVb) bzw. (VIIb) gebildet; weiterhin konnen Produkte einer Fragmentierung am C-5 /C-6 wie (V) auftreten].

A concise diastereoselective synthesis of the natural (2R,3S)-2-hydroxymethyl-3-hydroxy pyrrolidine

Abstract (2R, 3S)-2-hydroxymethyl-3-hydroxy pyrrolidine 4, a constituent of Castanospermum australe, 1 was synthesized from (S)-pyroglutamic acid through diastereoselective epoxidation of α, β-unsaturated pyrrolidone 8.

In vitro cytostatic activity of 9-demethoxyporothramycin B

Summary (11a S )-9-Demethoxyporothramycin B was synthesized in an enantiomerically pure form from ( S )-pyroglutamic acid. It exhibits marked in vitro cytostatic activity in several cancer cell lines. MDR + cell lines are not significantly more resistant to this compound than their MDR- counterparts.

A short synthesis of C-2 symmetric (2S,5S) pyrrolidine-2,5 dicarboxylic acid, a constituent of red alga Schizymenia dubyi

Abstract (2S, 5S) pyrrolidine-2,5-dicarboxylic acid 1 was synthesized from (5S) N-methoxycarbonyl-5-ethoxyethoxy-methyl pyrrolidin-2-one 2 by a simple and efficient way. 1

Partial synthesis of vinblastine-type alkaloids

Application of a modification of Polonovskis reaction facilitates partial synthesis of vinblastine-type alkaloids.

Enantioselective syntheses of (R)-3-phenyl GABA, (R)-baclofen and 4-arylpyrrolidin-2-ones

Abstract Enantioselective synthesis of (R)-4-amino-3-phenylbutyric acid and (R)-baclofen has been achieved through a diastereoselective conjugate addition of cyanide to enantiomericaly pure 2-(2-arylethenyl)oxazolines, followed by chemoselective reduction into cyclic amidines.

1,3-Dipolar cycloadditions of nitrones to α,β-unsaturated γ-lactams derived from (S)-pyroglutaminol☆

Abstract α,β-Unsaturated γ-lactams undergo regio- and stereoselective 1,3-dipolar cycloadditions with N-benzyl and N-methyl nitrones and can act as acceptors in conjugate addition of N-methylhydroxylamine. These reactions give access to highly functionalized pyrrolidones.

Enantioselective synthesis of 2,3-disubstituted piperidines from (S)-methylpyroglutamate

Abstract N -methoxy- N -methylamide derived from ( S )-methylpyroglutamate was prepared in good yield and allowed the addition of Grignard reagents. Erythro ( 2S )-1-benzyl-2-hydroxybenzyl pyrrolidine obtained by this way was converted into ( 2S,3R )-1-benzyl-3-hydroxy-2-phenylpiperidine and its chloro analog.

α-Hydroxylation of β-dicarbonyl compounds

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

Stereocontrolled Synthesis of Enantiopure Substituted 4-Aminopyrrolidin-2-ones

Abstract The highly diastereoselective conjugate addition of N -benzylhydroxylamine and benzylamine to α,β-unsaturated lactam 3 provided an efficient entry to enantiopure (4 S ,5 S )-4-amino-5-hydroxymethylpyrrolidin-2-ones.