Propylphosphonic anhydride → Camptothecin

Participants

Reaction Steps

A solution of 2.0 g (0.10 mmoles) of m-PEG20k acid, 60 mg (0.06 mmoles) of diaminopimelic camptothecin TFA salt, 0.064 ml (0.10 mmoles) of a 50% solution of 1-propanephosphonic acid cyclic anhydride in ethyl acetate and 25 mg (0.20 mmoles) of N-dimethylamino pyridine in 20 ml of dry dichloromethane was stirred at room temperature overnight followed by washing with 1% aqueous sodium bicarbonate and 0.1 N HCl solution. The organic layer was dried over anhydrous sodium sulfate, and the solvent was removed by distillation in vacuo. The residue was crystallized from 2-propanol to yield 1.85 g (93% yield) of product.

Provenance & Evidence