Acetic Acid → (E)-(6R,7R)-3-[1-(4-Amino-benzyl)-2-oxo-pyrrolidin-3-ylidenemethyl]-8-oxo-7-(2-phenylsulfanyl-acetylamino)-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid

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Reaction Steps

(E)-(6R,7R)-3- [1-(4-allyloxycarbonylamino-benzyl)-2-oxo-pyrrolidin-3-ylidenemethyl]-8-oxo-7-(2-phenylsulfanyl-acetylamino)-5-thia-1-aza-bicyclo[4.2.0]oct-2-ene-2-carboxylic acid imidazole salt (1:1) (400.0 mg, 0.57 mmol) was suspended in 20 ml dichloromethane and treated with N,O-bis(trimethylsilyl)-trifluoroacetamide (240.7 ml, 9.11 mmol). After 15 min, bis(triphenylphosphine)palladium(II) chloride (10.0 mg, 0.014 mmol), acetic acid (0.65 ml, 11.4 mmol) and tributyltin hydride (1.53 ml, 5.70 mmol) were added. After 45 min the suspension was poured under stirring on 250 ml diethyl ether, containing 3 ml of a hydrochloric acid-saturated diethyl ether solution and was stirred for 1 h. The solid material was collected by filtration, suspended in 4 ml water: acetonitrile (1:1) and the pH was adjusted to 2 with 1M hydrochloric acid. To the suspension an equal amount of MCI gel (75-150μ, Mitsubishi Kasei Corporation) was added, the organic solvent was evaporated and the residue was chromatographed on MCI gel (75-150μ, Mitsubishi Kasei Corporation) with a gradient of water:acetonitrile (9:1, 4:1, 2:1, 1:1, 1:3). The organic solvent was evaporated and the aqueous phase was freeze-dried.

Provenance & Evidence