4-Nitrobenzyl chloroformate → HCID 56624843, compound

HRID 851354Notes

Reaction equation

[OH:1][C@H:2]([C@@H:4]1[C@@H:7]([S:8][CH3:9])[N:6]([C:10](=[C:15]([CH3:17])[CH3:16])[C:11]([O:13][CH3:14])=[O:12])[C:5]1=[O:18])[CH3:3].Cl[C:20]([O:22][CH2:23][C:24]1[CH:29]=[CH:28][C:27]([N+:30]([O-:32])=[O:31])=[CH:26][CH:25]=1)=[O:21]>CN(C)C1C=CN=CC=1.ClCCl.C(OCC)(=O)C>[CH3:16][C:15]([CH3:17])=[C:10]([N:6]1[C@H:7]([S:8][CH3:9])[C@@H:4]([C@@H:2]([O:1][C:20]([O:22][CH2:23][C:24]2[CH:25]=[CH:26][C:27]([N+:30]([O-:32])=[O:31])=[CH:28][CH:29]=2)=[O:21])[CH3:3])[C:5]1=[O:18])[C:11]([O:13][CH3:14])=[O:12]

Participants

Conditions

Temperature: 0 °C

Procedure

To a solution of methyl 2-[(3S,4R)-3-{(1S)-1-hydroxyethyl}-4-methylthio-2-oxoazetidin-1-yl]-3-methylbut-2-enoate (376 mg) and 4-dimethylaminopyridine (336 mg) in dichloromethane (3 ml) was added p-nitrobenzyl chloroformate (358 mg) at -30° C. under a nitrogen atmosphere. After stirring for one hour at 0° C., the mixture was diluted with ethyl acetate and washed with dilute hydrochloric acid, water, a dilute aqueous sodium bicarbonate, and brine. Drying over magnesium sulfate and the removal of the solvent left an oil (635 mg), which was chromatographed on silica gel (25 g) eluting with 10-25% ethyl acetate in hexane to afford methyl 3-methyl-2-[(3S,4R)-4-methylthio-3-{(1S)-1-(p-nitrobenzyloxycarbonyloxy)ethyl}-2-oxoazetidin-1-yl]-but-2-enoate (566 mg) as an oil.

Workup

washwashed with dilute hydrochloric acid, water
dry with materialDrying over magnesium sulfate
customthe removal of the solvent
waitleft an oil (635 mg), which
customwas chromatographed on silica gel (25 g)
washeluting with 10-25% ethyl acetate in hexane

Sources & evidence

ORD record: ord-415920c75a564bc8a57d087478b4abc6
Source dataset: uspto-grants-1983_05
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04383945

Reaction notes

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