Sodium Bicarbonate → 1-Benzhydryl-3-cyclopropyl-3-fluoroazetidine hydrochloride

Participants

Reaction Conditions

Reaction Steps

Saturated NaHCO3 (100 ml) was added to a suspension of 1-Benzhydryl-3-cyclopropylazetidin-3-ol hydrochloride (7.78 g, 24.50 mmol) in ethyl acetate (100 ml). The mixture was transferred to a separating funnel and shaken vigorously until all of the solid had dissolved. The organic layer was separated and the aqueous layer extracted further with ethyl acetate (50 ml). The combined organic extracts were dried (Na2SO4) and concentrated to an oil. The oil was dissolved in dichloromethane (100 ml) and cooled to −78° C. [bis(2-methoxyethyl)amino]sulfur trifluoride (5.98 g, 27.05 mmol, 5.0 ml) was added dropwise and the solution stirred for 30 mins at −78° C. and then warmed to 0° C. and stirred for a further 1 hr. Reaction was quenched with Saturated NaHCO3 (50 ml) and brine (50 ml) and the aqueous layer extracted with dichloromethane (50 ml). The combined organic extracts were dried (Na2SO4) and concentrated to give a yellow oil. The crude was purified on silica gel, eluting with 5% ethyl acetate/petrol. The resulting alcohol was dissolved in ether (100 ml) and the solution cooled to 0° C. A solution of HCl in ether (2M, 25 ml) was then added dropwise over 5 minutes. The HCl salt precipitated from solution. The resulting slurry was stirred at 0° C. for an additional 10 minutes then filtered. The filter cake was washed with ether (20 ml) and the solid dried under vacuum. This furnished the product as a white solid (4.71 g, 61%). 1H NMR d4-MeOH δ 0.30-0.52 (4H, m), 1.22 (1H, brs), 4.01-4.23 (4H, m), 5.50-5.60 (1H, brs), 7.13-7.46 (10H, m); ES+ 282.

Provenance & Evidence