No abstract

The a-amino-group of homocysteine thiolactone shows a reactivity analogue to that of homoserine lactone ; in a-benzyloxycarbonylamino-y-thiobutyrolactone the reactivity of the carbonyl group to nucleophilic attacks is much less than that of the analogous O-lactone.By using homocysteine thiolactone as aminating agent, peptide y-thiolactones have been synthesised from N-protected amino-acids. By using or-benzyloxycarbonylamino-y-thiobutyrolactone, amides and mixed dioxopiperazines of homocystine have been obtained.

Nous avons poursuivi I'Ctude de la rkaction de certains sels sodCs de dCrivCs de I'acide amino-3-cyano-2-thioacrylique avec des dCrivCs halogCnCs. L'action de mtthylcCtones a-halogCnCes a permis d'obtenir dans certaines conditions soit des dCrives d'acide acyl-5-diamino-2,4-thiophene-3-carboxylique soit des ddrives d'acide thiazoline-Axadtique. L'acttylation de certains thiophenes a conduit i la formation de thienopyrimidines.Reactions of sodium salts of substituted 3-amino-2-cyano-3-thioacrylic esters and amides with ahalomethylketones were studied. Conditions were found which led to the synthesis of either 5-acyl-2,4-diaminothiophene-3-carboxylic esters and amides or thiazoline-A'=-acetic esters and amides. Some thiophene-3-carboxamides were also transformed into thienopyrimidines upon acetylation.

The synthesis of new derivatives of 2'-hydroxychalcone, such as esters, sulfonates, and thiocarbamates, prepared for evaluation as antiparasitic agents as well as new heterocyclic chalcone analogues prepared for the same purpose, is described.

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