Simple Access to Isoxazole-Containing Heterocyclic Hybrids: Isoxazole/Oxazole and Isoxazole/Pyridine

Abstract The synthesis of substituted isoxazole–oxazole hybrids by the noncatalytic reaction methyl 2-diazo-2-(alkyl/aryl/hetarylisoxazol-5-yl)acetates with alkyl and aryl cyanides has been reported. According to DFT calculations, proceeds through intermediate formation a nitrile ylide its subsequent cyclization at carbonyl oxygen. acrylonitrile 2-diazo-2-(isoxazol-5-yl)acetate quite differently leads mixture cis trans isomers cyclopropanes, which, according are formed cycloaddition diazo-derived carbene C=C bond acrylonitrile. hetero-Diels–Alder 5-alkoxyoxazole moiety makes it possible obtain isoxazole–pyridine hybrids, albeit in low yield.