Acetic Anhydride → HCID 20461628, compound

HRID 543557Notes

Reaction equation

HRID 543557 reaction equation
[CH2:1]([CH:4]1[N:7]([C:8]([C:28]([O:30][CH2:31][C:32]2[CH:37]=[CH:36][CH:35]=[CH:34][CH:33]=2)=[O:29])=[P:9]([C:22]2[CH:27]=[CH:26][CH:25]=[CH:24][CH:23]=2)([C:16]2[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=2)[C:10]2[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=2)[C:6](=[O:38])[CH:5]1[CH:39]([OH:41])[CH3:40])[CH:2]=[CH2:3].[C:42](OC(=O)C)(=[O:44])[CH3:43]>ClCCl>[CH2:1]([CH:4]1[N:7]([C:8]([C:28]([O:30][CH2:31][C:32]2[CH:33]=[CH:34][CH:35]=[CH:36][CH:37]=2)=[O:29])=[P:9]([C:10]2[CH:11]=[CH:12][CH:13]=[CH:14][CH:15]=2)([C:22]2[CH:23]=[CH:24][CH:25]=[CH:26][CH:27]=2)[C:16]2[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=2)[C:6](=[O:38])[CH:5]1[CH:39]([O:41][C:42](=[O:44])[CH3:43])[CH3:40])[CH:2]=[CH2:3]

Participants

4

Reactant 2

HCID 7918Acetic AnhydrideHCID 20461600HCID 20461600, compound

Product 1

HCID 20461628HCID 20461628, compound

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

A mixture of one cis and two trans-isomers of 4-allyl-3-(1-hydroxyethyl)-1-(1-benzyloxycarbonyl-1-triphenylphosphoranylidenemethyl)azetidin-2-one (5.0 g) in dry dichloromethane (150 cm3) was treated with 4-N,N-dimethylaminopyridine (1.22 g) followed by acetic anhydride (2.27 g) and the solution was stirred overnight at room temperature. The solution was evaporated under reduced pressure and the residue was chromatographed using high performance liquid chromatography, eluting with a 6:4 ethyl acetate/60°-80° petroleum ether mixture. This gave one cis and two trans-isomers of 4-allyl-3-(1-acetoxyethyl)-1-(1-benzyloxycarbonyl-1-triphenylphosphoranylidenemethyl)azetidin-2-one. The yields were the cis isomer (1.10 g, 21%) one trans isomer (0.28 g, 5%) and the other trans isomer (1.23 g, 23%). The cis-isomer crystallised (m.p. 156°-160° decomp). The infra-red spectra of all three isomers were identical; νmax (CHCl3) 3000, 1730, 1635 and 1610 cm-1.

Workup

  1. customThe solution was evaporated under reduced pressure
  2. customthe residue was chromatographed
  3. washeluting with a 6:4 ethyl acetate/60°-80° petroleum ether mixture

Sources & evidence

ORD record
ord-e7c74131dedd4d1ab1df7603619e3c92
Source dataset
uspto-grants-1984_05
Patent number
US04446146

Reaction notes

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