Ethyl 2-methyl-2-(6-methyl-5-phenyl-2,3-dihydro-4-oxo-4H-1,3-oxazin-3-yl)-propionate → 2-(2,3-dihydro-6-methyl-4-oxo-5-phenyl-4H-1,3-oxazin-3-yl)-2-methylpropionaldehyde

HRID 1274876Notes

Reaction equation

[CH3:1][C:2]1[O:7][CH2:6][N:5]([C:8]([CH3:15])([CH3:14])[C:9](OCC)=[O:10])[C:4](=[O:16])[C:3]=1[C:17]1[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=1.[H-].[Al+3].[Li+].[H-].[H-].[H-]>O1CCCC1.CCOCC.[Cl-].[Na+].O>[CH3:1][C:2]1[O:7][CH2:6][N:5]([C:8]([CH3:14])([CH3:15])[CH:9]=[O:10])[C:4](=[O:16])[C:3]=1[C:17]1[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=1

Participants

Conditions

Temperature: -40 °C

Procedure

A solution of ethyl 2-(2,3-dihydro-6-methyl-4-oxo-5-phenyl-4H-1,3-oxazin-3-yl)-2-methylpropanoate (43 g) in tetrahydrofuran was added to lithium aluminium hydride (220 ml of a 1M solution in ether) with stirring at -40° C. After 1 hour the solution was cooled to -70° C., diluted with ether, and treated with brine via dropwise addition, initially at -70° C. and then at -30° C. After warning to room temperature the organic layer was dried (magnesium sulphate), evaporated and the residue purified by dry column chromatography on silica gel eluting with dichloromethane to give 2-(2,3-dihydro-6-methyl-4-oxo-5-phenyl-4H-1,3-oxazin-3-yl)-2-methylpropionaldehyde as a cream solid (22.5 g), NMR 1.35(s,6H), 1.95(s,3H), 5.25(s,2H), 7.22-7.38(m,5H), 9.42(s,1H).

Workup

temperatureAfter 1 hour the solution was cooled to -70° C.
customat -30° C
customAfter warning to room temperature
dry with materialwas dried (magnesium sulphate)
customevaporated
customthe residue purified
dry with materialby dry column chromatography on silica gel eluting with dichloromethane

Sources & evidence

ORD record: ord-45e166af6d364581ad0e1ed6a164f470
Source dataset: uspto-grants-2000_12
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06159902

Reaction notes

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