4-Nitro-1H-indazole synthesis

Yield:2942-40-7 99%

Reaction Conditions:

with sodium nitrite in water;acetic acid

Steps:

1.A A.
A. Preparation of 4-Nitroindazole from 2-Methyl-3-Nitro-Aniline Sodium nitrite (20 grams, 0.29 mol) was dissolved in 50 mL water. This solution was added all at once to 2-methyl-3-nitroaniline (20 grams, 0.13 moles) in glacial acetic acid near zero degrees C. The reaction was stirred vigorously with an overhead stirrer. An immediate precipitate occurred upon addition of sodium nitrite solution. The reaction was allowed to reach room temperature and stirred overnight. The precipitate was filtered off and the filtrate was concentrated in vacuo. The dark orange solid was suspended in water, filtered, and dried yielding 14-21 grams of a dark orange solid (99% yield).

References:

Eli Lilly and Company US6534504, 2003, B1

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