Cytarabine → urea Ara-C

Participants

Reaction Conditions

Reaction Steps

A solution of PEG-diamine dihydrochloride (6), (3.0 g, 0.08 mmol) in 80 mL of toluene is azeotroped for 2 hours. The solution is cooled to 30° C. followed by the addition of triphosgene (0.02 g, 0.06 mmol) and DIEA (0.07 g, 0.5 mmol). This mixture is stirred for 3 hours at 70-80° C. followed by cooling to room temperature and addition of 60 mL of ethyl ether. PEG-isocyanate (7) is collected by filtration under nitrogen, and immediately added to a solution of 1 (0.27 g, 1.1 mmol) and DMAP (0.14 g, 1.1 mmol) in anhydrous pyridine (30 mL) and the reaction is stirred at 45° C. overnight. The solvent is removed in vacuo, and the residue is crystallized from IPA to yield PEG-urea-Ara-C (8).

Provenance & Evidence