SYNTHESIS OF 2-HALO-2<i>Н</i>-AZIRINE-2-CARBOXYLIC ACID AMIDES AND ESTERS BY ISOMERIZATION OF 5-(DIALKYLAMINO/ALKOXY)-SUBSTITUTED ISOXAZOLES, CATALYZED BY IRON(II) SULFATE

Abstract

N,N-Dialkylamides and esters of 2-(chloro/bromo/iodo)-2H-azirine-2-carboxylic acids were synthesized by isomerization of 4-halo-5-(dialkylamino/alkoxy)isoxazoles in the presence of catalytic amounts of FeSO₄·7H₂O. The use of iron(II) sulfate as catalyst, compared to its chloride, provides the advantage of avoiding halide exchange products in isomerization reactions of 4-bromo- and 4-iodoisoxazoles, as well as prevents catalyst deactivation by the 5-amino substituent of isoxazole, compared to rhodium(II) carboxylates.