Triethyl phosphonoacetate → Ethenyl-3-cephem-4-carboxylic acid

Beteiligte Stoffe

Reaktionsschritte

A suspension of 200 mg of 7-amino-3-formyl-3-cephem-4-carboxylic acid in 2 ml of THF is treated at room temperature with 1.08 ml of BSA. The reaction mixture is stirred at room temperature for 10 minutes. A clear solution is obtained containing N,O-bistrimethylsilyl-7-amino-3-formyl-3-cephem-4-carboxylic acid. The solution is cooled to 0° and treated dropwise with a mixture of 197 mg of diethylethoxycarbonylmethyl-phosphonate and 98 mg of potassium tert.butylate in 2 ml of THF. After 18 hours stirring at 0° the reaction mixture is worked up as described in example 23). 39 mg (15.5%) of 7-amino-3[E)-2-ethoxycarbonyl]ethenyl-3-cephem-4-carboxylic acid as a brown coloured powder are thus obtained.

Herkunft & Nachweise