Phosphorus tribromide → benzyl 2-(6-bromomethyl-2,3-dihydro-4-oxo-5-phenyl-4H-1,3-oxazin-3-yl)-2-methylpropanoate

Participants

Reaction Conditions

Reaction Steps

A solution of phosphorus tribromide (5.1 ml) in ether was added during 0.5 hour to a solution of benzyl 2-(2,3-dihydro-6-hydroxymethyl-4-oxo-5-phenyl-4H-1,3-oxazin-3-yl)-2-methylpropanoate (61.1 g) in a mixture of ether and tetrahydrofuran at -78° C. The mixture was then stirred at -10° C. for 4 hours and at room temperature for 1 hour, then washed (water), dried (magnesium sulphate) and evaporated. Purification of the residue by dry column chromatography on silica gel gave benzyl 2-(6-bromomethyl-2,3-dihydro-4-oxo-5-phenyl-4H-1,3-oxazin-3-yl)-2-methylpropanoate (46.1 g), NMR(CDCl3) 1.5(s,6H), 3.8(s,2H), 5.05(s,2H), 5.3(s,2H), 7.2(s,5H).

Provenance & Evidence