A process for the production of azithromycins by methylation of the nitrogen atom in position 9 of the ring structure in 9-deoxo-9a-aza-9a-homoerythromycins in the presence of formaldehyde and in the presence of a reducing agent in non-halogenated solvent; and azithromycin which is free from halogenated organic solvent in a stable anhydrous form; or in the form of a solvate with non-halogenated solvent with the exception of water.
展开▼