Hydrazine hydrate (1:1) → 5-fluoro-3-(1-methyl-4-piperidinyl)-1H-indazole

Participants

Reaction Steps

A mixture of 4-(2,5-difluorobenzoyl)-1-methylpiperidine of Example 111 (38.5 g, 0.16 moles) and hydrazine monohydrate (79.5 g, 1.59 moles) was heated in an autoclave at 150° for 22 hours. The autoclave was cooled in an ice bath and then opened. The reaction mixture was poured into H2O, causing the product to crystallize. The product was collected and then recrystallized twice from toluene to yield 8.2 g (22%) of 5-fluoro-3-(1-methyl-4-piperidinyl)-1H-indazole, m.p. 202°-204°.

Provenance & Evidence