Iodine → N'-(Desmethyl)azithromycin

Participants

Reaction Conditions

Reaction Steps

Azithromycin 1 (0.80 g, 1.02 mmol) and sodium acetate (NaOAc) (0.712 g, 8.06 mmol) were dissolved in 80% aqueous MeOH (25 mL). The solution was heated to 50° C. followed by addition of iodine (I2) (0.272 g, 1.07 mmol) in three batches within 3 minutes. The reaction was maintained at a pH between 8 and 9 by adding 1N sodium hydroxide (NaOH) (1 mL) at 10 min and 45 minute intervals. The solution turned colorless within 45 minutes. Stirring was continuedfor 2 hours. TLC (CH2Cl2/MeOH/NH4OH 10:1:0.05) after 2 hours showed a single major product (Rf=0.66). The reaction was cooled to room temperature, poured into H2O (75 mL) containing NH4OH (1.5 mL) and extracted with CHCl3 (3×30 mL). The combined organic layers were washed with H2O (30 mL) containing NH4OH (1.5 mL), dried over Na2SO4 and the solvent evaporated to give a white residue. The crude was purified on a silica gel column eluting with CH2Cl2/MeOH/NH4OH 18:1:0.05 to 10:1:0.05 to provide compound 2 (0.41 g, 55%).

Provenance & Evidence