Sodium borohydride → 1-tosyl-4,5,6,7-tetrahydro-1H-indazol-4-ol

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Reaction Steps

To a solution of 1-tosyl-6,7-dihydro-1H-indazol-4(5H)-one (5 g, 17.22 mmol) in EtOH/THF (30 mL/30 mL)) was added NaBH4 (1.3 g, 34.44 mmol) under ice-bath. The mixture was stirred for 1 h at this temperature and quenched with aqueous NH4Cl solution. Removed the solvent under reduced pressure and extracted with DCM and the combined organic layer was washed with water, brine and dried over anhydrous Na2SO4. The organic layer was concentrated in vacuo and the residue 1-tosyl-4,5,6,7-tetrahydro-1H-indazol-4-ol (4.94 g, yield 98.2%) was used directly to next step. MS-ESI (m/z): 293 (M+1)+ (Acq Method: 10-80AB_2 min; Rt: 1.01 min)

Provenance & Evidence