Sulfuric Acid → HCID 178481951, compound

Participants

Reaction Steps

Another method of making 5-trifluoromethyl-3-hydroxypyrazole involves reacting the ethyl 4,4,4-trifluoroacetoacetate directly with the methylhydrazine in ether to form a mixture of the intermediates 5-hydroxypyrazolidin-3-one and 3-hydroxypyrazolidin-5-one and dehydration of these intermediates by the addition of sulfuric acid in chloroform to form a mixture of the 3- and 5-hydoxypyrazoles. The desired isomer can be separated as described above. Alternatively, 2,4,4 trifluoroacetoacetate can be reacted in a like manner to give 1-methyl-3-hydroxy-4-fluoro-5-difluoromethylpyrazole.

Provenance & Evidence