3-((Acetyloxy)methyl)-7-amino-8-oxo-5-thia-1-azabicyclo(4.2.0)oct-2-ene-2-carboxylic acid → HCID 20499081, compound

Participants

Reaction Steps

A mixture of 1 g of 3-acetyloxymethyl-7-amino-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid and 1 g of 2-amino-2-difluoromethyl-3-(5-imidazolyl)propionic acid chloride wherein the free amino groups are protected with tertiary-butoxycarbonyl in 50 ml of ethyl acetate is refluxed for 2 hours after which the solvent is removed leaving a residue which is chromatographed on silica gel using benzene-acetone as the eluant to give 7-[[2-amino-2-difluoromethyl-3-(5-imidazolyl)propionyl]amino]-3-acetoxymethyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid wherein the amino groups are protected with tert-butoxycarbonyl. The protected cephalosporin compound is treated with trifluoroacetic acid for 1/2 hour at 25° C. under nitrogen atmosphere then diluted with ether until precipitation stops and filtered to give the di-trifluoroacetic acid salt of the title cephalosporin which can be converted to free base by use of ion exchange resin.

Provenance & Evidence