反应详情

A mixture of ethyl 4-(2,3-dihydro-6-methyl-4-oxo-5-phenyl-1,3-oxazin-3-yl)-4-methyl-3-oxo-pentanoate (500 mg), N-bromosuccinimide(258 mg) and benzoyl peroxide (10 mg) was refluxed under a lamp whilst stirring in benzene for 10 minutes. After cooling, the solid was filtered, the filtrate evaporated and the residue purified by column chromatography (hexane/ethyl acetate 4:1) to give ethyl 2-bromo-4-(2,3-dihydro-6-methyl-4-oxo-5-phenyl-1,3-oxazin-3-yl)-4-methyl-3-oxo-pentanoate (Compound 190, 400 mg ) as a yellow gum, NMR 1.21(t,3H), 1.55(d,6H), 1.94(s,3H), 4.15(q,2H), 5.23(s,1H), 5.26(d--d,2H) and 7.21-7.37(m,5H).

1. temperaturewas refluxed under a lamp
2. temperatureAfter cooling
3. filtrationthe solid was filtered
4. customthe filtrate evaporated
5. customthe residue purified by column chromatography (hexane/ethyl acetate 4:1)