1H-Indazole,4-broMo-7-(trifluoroMethyl)- synthesis

Yield:1186334-79-1 42%

Reaction Conditions:

with hydrazine hydrate in 1,2-dimethoxyethane; for 3 h;Reflux;

Steps:

76.2

Step 2: To a solution of 6-bromo-2-fluoro-3-trifluoromethyl-benzaldehyde (1.0 g, 3.7 mmol) in dmethoxyethane, DME (5 ml.) was added hydrazine hydrate (5 ml_). The mixture was refluxed for 3 hours, and then cooled to room temperature. The solvent was evaporated, water (100 ml.) was added and the reaction mixture was extracted with ethyl acetate (3 x 30 ml_). The combined organic layers were dried over sodium sulfate, filtered, and then concentrated in-vacuo. The residue was purified by silica gel chromatography to afford 4-bromo-7-(trifluoromethyl)-1 H-indazole in 42% yield. MS 264.9 [M+H].

References:

WO2009/108838,2009,A1 Location in patent:Page/Page column 92