Hydrochloric Acid → 2-(2,3-dihydro-6-methyl-4-oxo-5-phenyl-4H-1,3-oxazin-3-yl)-2-methyl-1-(2-methylenecyclopentyl)propan-1-ol

HRID 1274882Notes

Reaction equation

[C:1]1([CH2:6]Br)[CH2:5][CH2:4][CH2:3][CH:2]=1.[CH3:8][C:9]1[O:14][CH2:13][N:12]([C:15]([CH3:19])([CH3:18])[CH:16]=[O:17])[C:11](=[O:20])[C:10]=1[C:21]1[CH:26]=[CH:25][CH:24]=[CH:23][CH:22]=1.C(OCC)(=O)C.Cl>O1CCCC1.[Zn]>[CH3:8][C:9]1[O:14][CH2:13][N:12]([C:15]([CH3:18])([CH3:19])[CH:16]([CH:2]2[CH2:3][CH2:4][CH2:5][C:1]2=[CH2:6])[OH:17])[C:11](=[O:20])[C:10]=1[C:21]1[CH:26]=[CH:25][CH:24]=[CH:23][CH:22]=1

Participants

Conditions

Temperature: 53 °C

Procedure

A solution of (cyclopent-1-enyl)methylbromide (3.8 g) in tetrahydrofuran was added to a stirred mixture of 2-(2,3-dihydro-6-methyl-4-oxo-5-phenyl-4H-1,3-oxazin-3-yl)-2-methylpropionaldehyde (3.5 g) and zinc powder(1.6 g) in tetrahydrofuran at 20° C. under an inert atmosphere. The temperature increased to 53° C. slowly and after 2 hours, ethyl acetate and hydrochloric acid (1N) were added and the organic phase washed with brine, dried (magnesium sulphate), evaporated and purified by silica gel column chromatography, eluting with n-hexane/ethyl acetate (2:1) to give 2-(2,3-dihydro-6-methyl-4-oxo-5-phenyl-4H-1,3-oxazin-3-yl)-2-methyl-1-(2-methylenecyclopentyl)propan-1-ol (3.66 g), NMR: 1.46(s,3H), 1.61(s,3H), 1.88(s,3H), 1.5-1.9(4H), 2.24(2H), 2.50(1H), 3.24(d,1H), 3.80(s,1H), 4.93(s,1H), 5.06(s,1H), 5.19(d,1H), 5.26(d,1H), 7.22-7.38(5H).

Workup

washthe organic phase washed with brine
dry with materialdried (magnesium sulphate)
customevaporated
custompurified by silica gel column chromatography
washeluting with n-hexane/ethyl acetate (2:1)

Sources & evidence

ORD record: ord-e82b0abb80c2479bad4bbeb0c4b65239
Source dataset: uspto-grants-2000_12
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06159902

Reaction notes

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