Ammonium Chloride → {2-[6-(1-[(1,1-Dimethylethyl)(dimethyl)silyl]-1H-indol-4-yl)-1-(phenylsulfonyl)-1H-indazol-4-yl]-1,3-oxazol-5-yl}methanol

Participants

Reaction Conditions

Reaction Steps

To a solution of ethyl 2-[6-{1-[(1,1-dimethylethyl)(dimethyl)silyl]-1H-indol-4-yl}-1-(phenylsulfonyl)-1H-indazol-4-yl]-1,3-oxazole-5-carboxylate (containing an impurity consistent with ethyl 2-[6-chloro-1-(phenylsulfonyl)-1H-indazol-4-yl]-1,3-oxazole-5-carboxylate)(0.84 g) in dichloromethane (10 ml) at −20° C. was added diisobutylaluminum hydride (2.68 ml, 2.68 mmol, 1M in hexanes). The reaction mixture was stirred at −20° C. for 2 h then 10% ammonium chloride solution (10 ml) added. The mixture was stirred for 5 min then extracted with dichloromethane (10 ml), the layers separated (hydrophobic frit) and the organic purified by silica gel chromatography, eluting with a gradient of cyclohexane and ethyl acetate. The desired fractions were concentrated to give the title compound as a pale yellow solid (0.36 g), which by LCMS contained an impurity consistent with 2-[6-chloro-1-(phenylsulfonyl)-1H-indazol-4-yl]-1,3-oxazol-5-yl}methanol. LCMS (Method A): Rt 1.55 mins, MH+585 (and Rt 1.11 mins, MH+390 consistent with {2-[6-chloro-1-(phenylsulfonyl)-1H-indazol-4-yl]-1,3-oxazol-5-yl}methanol impurity).

Provenance & Evidence