N-bromobutanimide → (5E)-5-{(2E)-2-[(1-bromo-2-methylindolizin-3-yl)carbonyl]but-2-en-1-ylidene}-4-methylidene-2-phenyl-4,5-dihydro-6H-1,3-oxazin-6-one

Participants

Reaction Steps

N-Bromosuccinimide (10.64 g; 59.8 mmol) is added portionwise to a solution of (5E)-4-methylidene-5-{(2E)-2-[(2-methylindolizin-3-yl)carbonyl]but-2-en-1-ylidene}-2-phenyl-4,5-dihydro-6H-1,3-oxazin-6-one (22.8 g; 59.8 mmol) in 350 mL of DCM and 105 mL of NMP. After 10 min of stirring at ambient temperature, the yellow precipitate formed is filtered off, washed with DCM and dried under vacuum to give 23.2 g (85%) of the yellow powder.

Provenance & Evidence