Reactions of nitrile oxides and nitrile imines with 4‐arylidene‐2‐phenyl‐5(4<i>H</i>)‐thiazolones

Abstract

Abstract Nitrile oxides 2a , b and nitrile imines 2c – e are added to the C  C bond of 4‐arylidene‐2‐phenyl‐5(4 H )‐thiazolones 1 to afford spiro‐isoxazolines 3a – d and spiro‐pyrazolines 3e – j , respectively. The cycloaddition reactions are regioselective and only one of the two possible regioisomers is isolated. Reactions of the cycloadducts with nucleophiles lead to isoxazole and pyrazole derivatives 8 and 10 by opening of the thiazolone ring.