2,6-Lutidine → 5-(3-Cyanophenyl)-1,3-dimethyl-2,4-dioxo-1,2,3,4,7,8-hexahydropyrimido[4,5-a]indolizin-10-yl trifluoromethanesulfonate

Participants

Reaction Steps

Trifluoromethanesulfonic anhydride (221 μL, 1.31 mmol) was added to an ice-cooled solution of 3-(1,3-dimethyl-2,4,10-trioxo-1,2,3,4,7,8,9,10-octahydropyrimido[4,5-a]indolizin-5-yl)benzonitrile (step 7) (350 mg, 1.01 mmol) and 2,6-lutidine (176 μL, 1.51 mmol) in DCM (5 mL). The solution was stirred at ice-bath temperature for 2 hours, further portions of 2,6-lutidine (88 μL, 0.78 mmol) and trifluoromethanesulfonic anhydride (85 μL, 0.50 mmol) were added. The reaction mixture was diluted with dichloromethane (40 mL) and was washed with water (2×20 mL) and sat. brine (1×20 mL). The organic phase was dried with magnesium sulfate and the solvent was removed under vacuum.

Provenance & Evidence