Hydrochloric Acid → (S)-tert-butyl 7-bromo-4-(cyclopropanecarbonyl)-3-methyl-3,4-dihydroquinoxaline-1(2H)-carboxylate

Participants

Reaction Steps

A 100-mL round bottomed flask fitted with a nitrogen inlet and magnetic stir bar was charged with (S)-tert-butyl 7-bromo-3-methyl-3,4-dihydroquinoxaline-1(2H)-carboxylate (4.75 g, 14.52 mmol), dichloromethane (50 mL), pyridine (1.996 mL, 24.68 mmol), and cyclopropanecarbonyl chloride (1.976 mL, 21.77 mmol). The reaction mixture was stirred at rt for 2 h and then 1 M aqueous HCl solution (25 mL) was added. The organic layer was separated and concentrated under reduced pressure to afford (S)-tert-butyl 7-bromo-4-(cyclopropanecarbonyl)-3-methyl-3,4-dihydroquinoxaline-1(2H)-carboxylate (5.72 g, 99%) as a solid, which was used directly in next step. MS (ESI, pos. ion) m/z 395, 397 [M+1]+.

Provenance & Evidence