Potassium Phosphate, Tribasic → 1h-Indazole,4-bromo-1-(2,4-difluorophenyl)-6-methyl-

Participants

Reaction Steps

2,6-Dibromo-4-methylbenzaldehyde (2,4-difluorophenyl)hydrazone (Intermediate 12, 67.4 g, 0.167 mol), tripotassium phosphate (88.8 g, 0.418 mol), tris(dibenzylideneacetone)dipalladium(0) (3.4 g, 3.71 mmol) and racemic BINAP (2.09 g, 3.27 mmol) were heated in degassed 1,4-dioxane (1.125 L) under reflux for 4 days. The mixture was filtered through Celite, washing through with dichloromethane. The filtrate was evaporated under reduced pressure to give a dark brown residue which was dissolved in dichloromethane, absorbed onto silica gel, applied to a silica gel column (1 kg) and eluted with a gradient of 10 to 35% dichloromethane in hexane. Product containing fractions were combined and evaporated to give the title compound as a red solid (17.8 g).

Provenance & Evidence