SYNTHETIC METHOD FOR THE PREPARATION OF AN HYDRAZINE COMPOUND

Provided is a process for preparing the compound 3 (3) or a salt or a solvate thereof, the process comprising the steps of a) Mixing the compound 4 with a mineral acid (4); b) Adding a nitrite salt or an organic nitrite derivative to the reaction mass to form a diazonium salt; c) Adding a sulfur-containing reducing agent to the reaction mass to form a hydrazyl sulfur complex, such as a hydrazyl sulfite complex; d) Hydrolysing the hydrazyl sulfur complex to provide the compound 3 or a salt or solvate thereof; and e) Optionally isolating the compound 3 or a salt or solvate thereof. Further provided is the use of the compound 3 in the synthesis of 3-[5 -Amino-4-(3-Cyanobenzoyl)-Pyrazol-1-yl]-N-Cyclopropyl-4-Methylbenzamide.