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

HRID 377573Notes

Reaction equation

P(Br)(Br)[Br:2].O[CH2:6][C:7]1[O:12][CH2:11][N:10]([C:13]([CH3:25])([CH3:24])[C:14]([O:16][CH2:17][C:18]2[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=2)=[O:15])[C:9](=[O:26])[C:8]=1[C:27]1[CH:32]=[CH:31][CH:30]=[CH:29][CH:28]=1>CCOCC.O1CCCC1>[Br:2][CH2:6][C:7]1[O:12][CH2:11][N:10]([C:13]([CH3:25])([CH3:24])[C:14]([O:16][CH2:17][C:18]2[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=2)=[O:15])[C:9](=[O:26])[C:8]=1[C:27]1[CH:32]=[CH:31][CH:30]=[CH:29][CH:28]=1

Participants

Conditions

Temperature: -10 °C

Procedure

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).

Workup

washwashed (water)
dry with materialdried (magnesium sulphate)
customevaporated
customPurification of the residue
customby dry column chromatography on silica gel

Sources & evidence

ORD record: ord-e332b796c361411c81b06dd2545753c7
Source dataset: uspto-grants-2000_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06028032

Reaction notes

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