Dichloromethane → Diphenylmethyl 7-(2-thienylacetamido)-3-(1-acetoxyethyl)-3-cephem-4-carboxylate

Participants

Reaction Steps

To a solution of 7-(2-thienylacetamido)-3-(1-acetoxyethyl)-3-cephem-4-carboxylic acid (stereoisomer A: 88 mg) in mixture (5 ml) of methanol and methylene chloride (1:1) is added a solution of diphenyldiazomethane in ether until the red color of the solution does no more disappear at 55° C on standing. After 3 hours, the reaction mixture is concentrated to give the residue which is stirred in a mixture of ether and petroleum ether. The supernatant is removed, and resulting precipitate is recrystallized from petroleum ether to give diphenylmethyl 7-(2-thienylacetamido)-3-(1-acetoxyethyl)-3-cephem-4-carboxylate (stereoisomer A: 85 mg). m.p. 161-163° C. Yield: 70%.

Provenance & Evidence