1,1'-Carbonyldiimidazole → Tert-butyl 1-(cyclopropylsulfonylcarbamoyl)-2-(difluoromethyl)cyclopropylcarbamate

Participants

Reaction Steps

A mixture of 1-(tert-butoxycarbonylamino)-2-(difluoromethyl)cyclopropanecarboxylic acid (975 mg, 3.88 mmol) and CDI (755 mg, 4.66 mmol) in tetrahydrofuran (10 mL) was heated at reflux for 1 h. It was then cooled to rt and then cyclopropanesulfonamide (564 mg, 4.66 mmol) was added, followed by DBU (0.702 mL, 4.66 mmol). This mixture was stirred at rt for 18 h. It was then concentrated in vacuo, diluted with water and adjusted to pH=4 using 1 N HCl. The acidic solution was extracted with EtOAc, washed with water (5×15 mL), dried (MgSO4), and concentrated in vacuo to yield 1.6 g of the crude product as a white solid. Recrystallization from hexane/EtOAc gave 1.15 g (84%) of tert-butyl 1-(cyclopropylsulfonylcarbamoyl)-2-(difluoromethyl)cyclopropylcarbamate as a white solid. LC-MS, MS m/z 377 (M+1+Na).

Provenance & Evidence