Influence of conditions and N-substituent on the reactions of 6-methoxy-3-methyl-6,6a-dihydrofuro[3,4-d]isoxazol-4(3aH)-one with hydrazines

The reactions of the title compound with hydrazines are studied to shed light on the course of the reaction of γ-alkoxyfuran-2(5H)-ones with these binucleophiles. At room temperature, both unsubstituted hydrazine and phenylhydrazine in ethanol, or hydrazine and its methylderivative in ethanol–acetic acid, afforded good yields of 5-amino-, 5-phenylamino-, and 5-methylamino-6-hydroxy-3-methyl-3a,5,6,6a-tetrahydro-4H-pyrrolo[3,4-d]isoxazol-4-ones. Only the methylhydrazine, in ethanol at room temperature, gave a derivative of the isoxazolo[4,5-d]pyridazin-4(3aH)-one system. No pyridazinone derivative is obtained from phenylhydrazine.