Fernand Texier

Regioselectivite de la cycloaddition dipolaire-1,3 de munchnones aux alcenes electrophiles

Abstract The 1,3-dipolar cycloaddition of several substituted Munchnones with methyl α-cyanocinnamate and α-cyanocinnamonitrile leads to 2-pyrrolines which may be aromatized to pyrroles. This study shows the influence of steric factors on the regioselectivity of the reaction which is “ a priori ” difficult to predict.

Orientation de la cycloaddition d'oxazolones mesoioniques aux alcenes.

Resume The regioselectivity of the cycloaddition ofmesoionic oxazolones to alkenes has been found to be markedly dependent on the substituent groups present and an explanation is proposed.

Addition d'aroyl-2 aziridines, ylures d'azométhine potentiels, aux isocyanate et isothiocyanate de phényle

Abstract The cycloaddition of azomethine ylids, generated from the thermal ring opening of aroylaziridines, occurs at the CN double bond of phenylisocyanate in accordance with previous work in this area. The literature claimed a different behaviour with phenylisothiocyanate. We have shown that the authors assumptions are based on incorrect structure determination of the products. The addition occurs also on the CN double bond of phenylisothiocyanate and the evolution of the primary adduct (i.e. a thioimidazolidone) is explained by the formation of a biradical stabilized through a capto-dative effect. This biradical cyclises to the transient 1,3 thiazolidine 12A.

[Addition d'azlactones ylures d'azomethine potentiels aux esters acryliques et fumariques et au fumaronitrile : obtention de carbolactones.]

Abstract Addition of azlactones obtained from α-aminoacid derivatives in acetic anhydride to fumaric diester or dinitrile gave rise to compounds 6 or 7 . Addition of phenylalanine or the corresponding azlactone to acrylic esters in the same solvent led to carbolactone derivative 8 . The structure of these products deduced from their spectroscopic IR and NMR data was confirmed by X-ray measurements.

BILDUNG VON 4‐OXAZOLINEN MIT AZOMETHIN‐YLID‐VERHALTEN DURCH THERMOLYSE VON 4‐ACYL‐1,2,3‐TRIAZOLINEN

Die aus den α-Acylzimtsaureestern (I) und den Arylaziden (II) entstehenden cis- bzw. trans-Triazoline (III) geben bei der Thermolyse die 4-Oxazoline (VI), wobei cis- und trans-Formen zu gleichen Produkten fuhren.