Diazomethane reacts with 2-phenylazo-1, 3-diketones in ether containing a little methanol to give mainly simple methylene derivatives. On treatment of these epoxides with acidic reagents 3-acyl-1-phenylpyrazoles are formed, the methylene derivative from a- phenylazoacetylacetone giving the known 3-acetyl-5-methyl-1-phenylpyrazole. The mode of formation of the various products is discussed and conclusions regarding the structure of ...
