(Diethylamino)sulfur trifluoride → 7-N-(tert-Butoxycarbonyl)-8-[cyclopropyl(fluoro)methyl]-2-(trifluoromethyl)-5,6,7,8-tetrahydro[1,2,4]triazolo[1,5-alpha]pyrazine

Participants

Reaction Conditions

Reaction Steps

A solution of 200 mg (0.55 mmol) of [7-N-(tert-butoxycarbonyl)-2-(trifluoromethyl)-5,6,7,8-tetrahydro[1,2,4]triazolo[1,5-α]pyrazin-8-yl](cyclopropyl)methanol (prepared as outlined in Example 3, Step A) in 3.5 mL of dichloromethane was cooled to −78° C. and 0.406 mL (3.31 mmol) of (diethylamino)sulfur trifluoride (DAST) was added. The reaction mixture was stirred at −78° C. for 1 h, then warmed to ambient temperature and stirred overnight. The reaction mixture was partitioned between saturated aqueous sodium bicarbonate solution and dichloromethane. The aqueous phase was extracted with three portions of dichloromethane. The combined organic phases were washed with brine, dried over magnesium sulfate, and concentrated. Purification by HPLC (Gilson, YMC C-18, 10 to 90% acetonitrile/water gradient) gave the title compound.

Provenance & Evidence