反应详情

3 g of 14-bromo daunorubicin 13,13-diethoxy ketal, prepared as described in Example 2 from 2.5 g of daunorubicin hydrochloride and isolated by filtration after trituration with a small volume of water, was stirred overnight at 25°-30° C. in 150 ml of a 5% aqueous solution of oxalic acid, at which time hydrolysis of the ketal group was complete. The pH was adjusted to 3.5 using a 5% solution of sodium bicarbonate and then the reaction mixture was kept at 50° C. for 2 days, after which time quantitative HPLC analysis (using the conditions of USP XXI) of the reaction mixture showed the presence of 1.75 g of doxorubicin (as the free substance). Isolation by preparative HPLC using a RP-18 reverse-phase silica gel column gave 1.5 g of doxorubicin hydrochloride having a purity of 98.9%.