Iodine → N'-(Desmethyl)azithromycin

Participants

Reaction Conditions

Reaction Steps

Azithromycin 1 (0.80 grams (g), 1.02 millimoles (mmol)) and sodium acetate (NaOAc) (0.712 g, 8.06 mmol) were dissolved in 80% aqueous methanol (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 8-9 by adding 1N sodium hydroxide (NaOH) (1 mL) at 10 min and 45 minute intervals. The solution turned colorless within 45 minutes (min), however, stirring was continued for 2 hours (hr). TLC ethylene chloride(CH2Cl2)/MeOH/ammonium chloride (NH4OH) 10:1:0.05) after 2 hours showed a single major product (Rf=0.66). The reaction was cooled to room temperature (rt), poured into H2O (75 mL) containing NH4OH (1.5 mL) and extracted with chloroform (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 amine 2 (0.41 g, 55%).

Provenance & Evidence