4-Nitrobenzyl chloroformate → HCID 56629932, compound

HRID 1719262Notes

Reaction equation

[OH:1][CH: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]([CH: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 a mixture (1:3) of methyl 2-[(3S,4R)-3-{(1RS)-1-hydroxyethyl}-4-methylthio-2-oxoazetidin-1-yl]-3-methylbut-2-enoate (1.84 g) and 4-dimethylaminopyridine (1.23 g) in dichloromethane (20 ml) was added a solution of p-nitrobenzyl chloroformate (1.60 g) in dichloromethane (3 ml) at 0° C. After stirring at 0° C. for 1.5 hours, the mixture was diluted with ethyl acetate (150 ml) and washed with dilute hydrochloric acid, water, a dilute aqueous sodium bicarbonate, and brine. Drying over magnesium sulfate and removal of the solvent left an oil (3.1 g), which was chromatographed on silica gel (90 g) eluting with 10-25% ethyl acetate in hexane to give a mixture (1:3) of methyl 3-methyl-2-[(3S,4R)-4-methylthio-3-{(1RS)-1-(p-nitrobenzyloxycarbonyloxy)ethyl}-2-oxoazetidin-1-yl]-but-2-enoate (2.90 g) as an oil.

Workup

washwashed with dilute hydrochloric acid, water
dry with materialDrying over magnesium sulfate and removal of the solvent
waitleft an oil (3.1 g), which
customwas chromatographed on silica gel (90 g)
washeluting with 10-25% ethyl acetate in hexane

Sources & evidence

ORD record: ord-10a90607b062421ea7bb2183f6cac081
Source dataset: uspto-grants-1985_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04539152

Reaction notes

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