Pyridine → 2-Methyl-2-propanyl (2S,4S)-2-carbamoyl-4-fluoro-1-pyrrolidinecarboxylate

Participants

Reaction Conditions

Reaction Steps

A reactor was charged with (4S)-1-(tert-butoxycarbonyl)-4-fluoro-L-proline (130 g, 1 wt, 1 eq.), dichloromethane (520 mL, 4 vol), pyridine (55 mL, 0.4 vol, 1.2 eq), and Boc-anhydride (145 g, 1.1 wt, 1.2 eq.). The reaction solution was stirred at approximately 20° C. for 2 hours. The reactor was charged with ammonium bicarbonate (62 g, 0.5 wt, 1.44 eq), and was stirred at approximately 20° C. overnight. The reaction was filtered over a bed of celite (130 g, 1 wt), and the filter cake was washed with dichloromethane (260 mL, 2 vol). The filtrate was concentrated to a volume of 3 volumes, heptane (520 mL, 4 vol) was added, and again concentrated to a final volume of 3 volumes. Heptane (390 mL, 3 vol) was added, and the reaction was cooled to approx. 5° C. for 30 min.

Provenance & Evidence