4-Nitrobenzyl chloroformate → HCID 56637969, compound

HRID 1719263Notes

Reaction equation

HRID 1719263 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>[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

5

Reactant 2

HCID 782054-Nitrobenzyl chloroformateHCID 56636482HCID 56636482, compound

Product 1

HCID 56637969HCID 56637969, compoundYield 77.9%

Reagents, catalysts & solvents 2

HCID 142844-(Dimethylamino)pyridineCatalystHCID 6344DichloromethaneSolvent2×

Procedure

To a solution of a mixture (5:1) of methyl 2-[(3S,4R)-3-{(1RS)-1-hydroxyethyl}-4-methylthio-2-oxoazetidin-1-yl]-3-methylbut-2-enoate (755 mg) and 4-dimethylaminopyridine (440 mg) in dichloromethane (6 ml) was added dropwise a solution of p-nitrobenzyl chloroformate (660 mg) in dichloromethane (4 ml) during three minutes period at 0° C. After 1.5 hours, the solution was concentrated, taken up into ethyl acetate (40 ml), and washed with dilute hydrochloric acid, water and brine. The organic layer was dried over magnesium sulfate and evaporated to leave an oil. Chromatography on silica gel (50 g) eluting with 2-10% ethyl acetate in dichloromethane to give methyl 3-methyl-2-[(3S,4R)-4-methylthio-3-{(1R)-1-(p-nitrobenzyloxycarbonyloxy)ethyl}-2-oxoazetidin-1-yl]but-2-enoate (974 mg).

Workup

  1. concentrationthe solution was concentrated
  2. washwashed with dilute hydrochloric acid, water and brine
  3. dry with materialThe organic layer was dried over magnesium sulfate
  4. customevaporated
  5. customto leave an oil
  6. washChromatography on silica gel (50 g) eluting with 2-10% ethyl acetate in dichloromethane

Sources & evidence

ORD record
ord-50ada8a08a42413b979fd96cba87237c
Source dataset
uspto-grants-1985_09
Patent number
US04539152

Reaction notes

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