Boron tribromide → 4-[2-(6-Methyl-pyridin-2-yl)-5,6-dihydro-4H-pyrrolo[1,2-b]pyrazol-3-yl]-phenol

Participants

Reaction Steps

To a solution of 3-(4-methoxy-phenyl)-2-(6-methyl-pyridin-2-yl)-5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole (72 mg, 0.24 mmol) in methylene chloride (1 mL) is added boron tribromide (0.3 mL). The solution is stirred at ambient temperature for 3 h, then quenched with methanol. The mixture is concentrated in vacuo to a reddish solid. The solid is passed through a silica gel cartridge (methylene chloride, ethyl acetate, then acetone). The appropriate methylene chloride fractions are concentrated in vacuo to yield 4 mg (5.8%) of the title compound. The more polar fractions are concentrated in vacuo then treated with aqueous ammonium chloride and methanol. The mixture is concentrated in vacuo and the residue purified on a silica cartridge eluting as above. Appropriate fractions are combined and concentrated in vacuo to yield an additional 49 mg (71%) of the title compound.

Provenance & Evidence