Methylation of 3-methyl- and 3-phenyl-4-arylhydrazonoisoxazol-5-ones with methyl iodide and dimethyl sulfate

Methylation of 3-methyl-4-arylhydrazonoisoxazol-5-ones with methyl iodide affords both 2,3-dimethyl-4-arylazoisoxazol-5-ones and 3-methyl-4-(N-methylarylhydrazono)isoxazol-5-ones but with dimethyl sulfate only the former products are formed. 3-Phenyl-4-arylhydrazonoisoxazol-5-ones behave in a similar way on methylation with methyl iodide and dimethyl sulfate.