Preparation of 6-O-methyl erythromycin A crystal Form II - from erythromycin, treating with solvent, and isolating, useful as an antibiotic

摘要

Preparation of 6-O-methylerythromycin A crystal form II comprising: (a) converting erythromycin A to 6-O-methylerythromycin A; (b) treating 6-O-methylerythromycin A with a solvent selected from (i) an 1-5C alkanol (except ethanol or isopropanol), (ii) a 5-12C hydrocarbon, (iii) a 3-12C ketone, (iv) a 3-12C carboxylic ester (except isopropyl acetate), (v) a 4-10C ether, (vi) benzene (optionally substituted by one or more substituents selected from 1-4C alkyl, 1-4C alkoxy, nitro or halo), (vii) a polar aprotic solvent, (viii) a compound of formula HNR1R2 where R1, R2 = H or 1-4C alkyl (provided that R1 and R2 are not both H), (ix) water and a water miscible solvent selected from a water miscible organic solvent and a water miscible alkanol, (x) methanol and a second solvent selected from a 5-12C hydrocarbon, a 2-5C alkanol, a 3-12C ketone, a 3-12C carboxylic ester, a 4-10C ether, benzene (optionally substituted by one or more substituents selected from 1-4C alkyl, 1-4C alkoxy, nitro or halo), (xi) a 5-12C hydrocarbon, a 3-12C carboxylic ester, a 4-10C ether of from 4 to 10 carbon atoms, benzene (optionally substituted by one or more substituents selected from 1-4C alkyl, 1-4C alkoxy, nitro or halo), and a polar aprotic solvent; and (c) isolating the 6-O-methylerythromycin A form II crystals.