Boron tribromide → 8'-fluoro-5'-hydroxy-1'H-spiro[cyclohexane-1,4'-quinazolin]-2'(3'H)-one

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of 8′-fluoro-5′-methoxy-1′H-spiro[cyclohexane-1,4′-quinazolin]-2′(3′H)-one (2.34 g, 8.84 mmol) in DCM (250 mL) at 0 to 5° C. was added boron tribromide (11.07 g, 44.2 mmol) dropwise over 20 minutes under N2. The mixture was stirred at 5° C. for 10 mins and gradually allowed to warm up to ambient temperature. Stirring was continued at ambient temperature for 18 h and a further portion of BBr3 (5 g, 20 mmol) was added. The mixture was left to stir for a further 24 hours and quenched with saturated NaHCO3 solution (500 mL) at 10° C. over 30 minutes. The mixture was stirred at ambient temperature for 1 hour and the aqueous layer was separated from dichloromethane and extracted with ethyl acetate (2×500 mL). The organic layers were washed with saturated NaHCO3 solution (200 mL), water (300 mL), dried over anhydrous MgSO4, filtered and concentrated in vacuo at 40° C. to give the crude product. The crude material was slurred in tert-butylmethylether (10 mL) at 18 to 20° C. for 5 minutes, filtered and dried in vacuo at 40° C. to give 8′-fluoro-5′-hydroxy-1′H-spiro[cyclohexane-1,4′-quinazolin]-2′(3′H)-one (1.5 g, 68%) as a light-brown solid, purity (99.9%).

Provenance & Evidence