Hydrazine hydrate (1:1) → 2-[3-(4-Chlorophenyl)-4-cyclopropyl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl]acetohydrazide

Participants

Reaction Steps

50 mg (0.17 mmol) of [3-(4-chlorophenyl)-4-cyclopropyl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl]-acetic acid [preparation according to WO 2007/134862 Example 88A] were dissolved in 0.4 ml of methanol and diluted with 0.6 ml of toluene, and 128 μl (0.26 mmol) of trimethylsilyldiazomethane solution (2 M in hexanes) were then added dropwise until a slight yellow color remained. The reaction was stirred for 1 h and then evaporated to dryness. The residue was taken up in 1 ml of ethanol, 43 mg (0.85 mmol) of hydrazine hydrate were added and the mixture was stirred under reflux for 2.5 h. After cooling, the solution was concentrated under reduced pressure and the residue was dried under high vacuum. This gave 54 mg (96% of theory) of the title compound in a purity of 93% as a colorless solid.

Provenance & Evidence