[Figure not available: see fulltext.] 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.
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- Organic Chemistry