Iodine → N-Demethylerythromycin A

Participants

Reaction Conditions

Reaction Steps

20 g of erythromycin A (=27.2 mmole) and 11.2 g (=136.2 mmole) of sodium acetate were dissolved in 200 ml of an 8:2 methanol/water mixture. The solution was heated to 47° C. Then 6.9 g (=136.2 mmole) of iodine were added. The pH was kept at 8 to 9 by adding dilute aqueous sodium hydroxide solution. After 3 hours, the reaction mixture was worked up by pouring it into a mixture of 1 liter of water and 20 ml of ammonium hydroxide solution. The reaction mixture was extracted with ethyl acetate, and the organic extract was washed with ammonium hydroxide-containing water and concentrated. The crude product remaining after removal of the solvent was recrystallized from acetone/ammonium hydroxide solution 50:3. Melting point 143°-148° C.

Provenance & Evidence