Preparation of erythromycin A derivatives, comprises reacting erythromycin A 9-N-aryl hydrazone with halogenated triphenyl methane compound

摘要

Erythromycin A 9-N-aryl hydrazone or a salt or hydrochloride thereof is reacted with a halogenated triphenyl methane compound in the presence of an organic base and after protecting the hydroxyl groups in the 2' and 4'' positions with silyl groups the resulting compound is methylated with methyl chloride in the presence of an alkaline base and an organic solvent. Finally the protecting silyl and triphenylmethyl hydrazone groups are removed with an organic acid and an inorganic salt. A method for preparing erythromycin A derivatives comprises the following steps: (1) reacting erythromycin A 9-N-aryl hydrazone or a salt or hydrochloride thereof with a halogenated triphenyl methane compound in the presence of an organic base to form erythromycin A 9-N-triphenylmethyl hydrazone; (2) protecting the hydroxyl groups in the 2' and 4'' positions with silyl groups; (3) methylating with methyl chloride in the presence of an alkaline base and an organic solvent; and (4) removing the protecting silyl groups and the triphenylmethyl hydrazone with an organic acid and an inorganic salt.