The Journal of Antibiotics Chemical Modification of Erythromycins. Ix.1} Selective Methylation at the C-6 Hydroxyl Group of Erythromycin a Oxime Derivatives and Preparation of Clarithromycin
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چکیده
Although erythromycin A contains five hydroxyl groups, regioselective methylation at the C-6 hydroxyl group was achieved to the extent of 90%when a 9-0-substituted erythromycin A 9-oxime was employedas substrate. The methylation and its selectivity are dependent on an O-protecting group at the 9-oxime, solvent, base, and methylating reagent. In particular, the use ofa polar aprotic solvent is indispensable for the methylation. Among the 9-oxime derivatives, 2'-0,3'-7V-bis(benzyloxycarbonyl)-7V-
منابع مشابه
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