Ph. Viallefont

Nouvelles synthèses de l-amino-acids—I: Synthèse stèréospécifique de l-proline, cis(trans) méthyl-3(4) l-prolines

Abstract The Hofmann-Loffler-Freytag reaction, carried out by irradiation in sulphuric acid of N -chloro- l -amino-acids 3a-d , gives δ-chlorinated compounds which can be cyclized to l -prolines 4a-e . This convenient synthesis does not affect the asymmetric centres of the starting material giving prolines in optically-pure form directly without the need for resolution.

New routes to 1,4- benzodiazepin-2,5-diones

Abstract 1,4-benzodiazepin-2,5-diones have been synthesized in good overall yields by two routes, the first one by cyclisation of dipeptides prepared from Boc anthranilic acid and α-amino acid methyl esters, the second one by reaction of N-carboxy α-amino acid anhydrides with Boc anthranilic acid.

Synthesis of Heterocyclic α-Aminophosphonic Acids

Abstract Heterocyclic α-aminophosphonic acids derivatives were easily obtained by 1,3 dipolar cycloaddition of acetylenic compounds on azido α-aminophosphonic esters.

Diastereoselective Synthesis of Glycosyl-β-hydroxy-α-amino Esters

Abstract We report here the first synthesis of glycosyl-β-hydroxy-α-amino esters by the aldol condensation of a glycine enolate on the aldehyde function of a ribose (1a) or a galactose (1b).

From Oxazolines to Precursors of Aminoacids

Abstract After optimization of the reaction conditions, action of nucleophiles on the tosyl derivatives of 4-hydroxymethyl oxazolines 1 and 2 afforded precursors of α and β aminoacids.

Synthesis ofα-triazolylα-amino acid derivatives

SummaryWe report the synthesis ofα-triazolylα-amino esters by 1,3 dipolar cycloaddition of acetylenic compounds andα-azidoα-amino esters.

CHEMOENZYMATIC SYNTHESIS OF THE TWO ENANTIOMERS OF 7-AZATRYPTOPHAN

Abstract 7-Azatryptophan is an unnatural α-amino acid with a very potent fluorescent activity. It is used as a vehicle for probing the structure and dynamics of proteins and peptides. Diastereoselective alkylation, diastereoselective protonation and enzymatic resolution have been tested for preparing enantiomerically pure 7-azatryptophan.

Enantiospecific synthesis of quisqualic acid

Abstract A new enantiospecific route to (R)- or (S)-Quisqualic acid is established starting from (R)- or (S)-serine.

Synthesis of biheterocyclicα-amino acids

SummaryWe report here the synthesis of biheterocyclicα-amino acids by 1,3 dipolar cycloaddition of acetylenic compounds onα-azidoα-amino esters.

Neuroexcitatory amino acids: phosphonic analogue of kainic acid.

SummaryThe enantioselective synthesis of phosphonic analogue of kainic acid is described.