3-METHYL-1H-INDAZOLE

2-aminoacetophenone (81 g) was added to 600 ml of hydrochloric acid (37%), and the aqueous solution of NaNO2 (80 g of sodium nitrite was added to 400 ml of water) was added dropwise at 0 to 10 C for 1 hour, and SnCl2 H2O hydrochloric acid solution (200 g dissolved in 300 ml hydrochloric acid (37%)) was stirred overnight. The reaction solution into the ice water filtration, the filtrate adjusted PH = 8, A large amount of solid precipitated and filtered to give 71 g of an off-white solid in 90% yield.The above 2'-aminoacetophenone 81g was added to 600 ml of hydrochloric acid (mass to volume ratio 37%) and a NaNO2 aqueous solution (80 g of sodium nitrite was added to 400 ml of water) was added dropwise at a temperature of 0 to 10 C., keeping the temperature at 0-10 C. and stirring for 1 hour.At this temperature, a SnCl2 ·H2O hydrochloric acid solution (200 g of SnCl2 ·H2O dissolved in 300 ml of a 37% by mass mass ratio of hydrochloric acid) was slowly added dropwise, and the mixture was stirred overnight at the temperature of 0 to 10C, and the reaction solution was poured into ice water. Filtration, the filtrate was adjusted to slightly alkaline pH = 8, a large number of solids precipitated, filtered and dried to give an off-white solid 71g, yield 90%, purity 99.8%,