Cyclopentyl chloroformate → (R)-cyclopentyl 3-(6H-imidazo[1,5-a]pyrrolo[2,3-e]pyrazin-1-yl)piperidine-1-carboxylate

Participants

Reaction Steps

To a solution of (R)-1-(piperidin-3-yl)-6H-imidazo[1,5-a]pyrrolo[2,3-e]pyrazine hydrochloride (0.06 g, 0.19 mmol) in THF (1 mL) was added TEA (0.08 mL, 0.57 mmol) and the reaction was stirred at ambient temperature for about 10 min. To the reaction mixture was added cyclopentyl chloroformate (0.02 mL, 0.15 mmol, Waterstone) and the mixture was stirred at about 45° C. for about 18 h. The reaction mixture was cooled to ambient temperature and concd under reduced pressure. The crude material was dissolved in DCM (5 mL) and washed with water (5 mL). The organic layer was separated and the aqueous layer was back extracted with DCM (2 mL). The combined organic extracts were dried over anhydrous MgSO4, filtered, and concd under reduced pressure. The material was purified by silica gel chromatography eluting with a gradient of 0-5% MeOH in DCM to afford (R)-cyclopentyl 3-(6H-imidazo[1,5-a]pyrrolo[2,3-e]pyrazin-1-yl)piperidine-1-carboxylate (0.015 g, 21%): LC/MS (Table 1, Method b) Rt=1.87 min; MS m/z: 354 (M+H)+.

Provenance & Evidence