4-Nitrobenzyl chloroformate → HCID 56624843, compound

HRID 1719261Notes

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-5253a5856fb342ff9dd7aa0440da7f03
Source dataset: uspto-grants-1985_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04539152

Reaction notes

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