Patent ID: 6342590
Filing Date: 2002-01-29
Classification: C07H

Abstract:
A process for preparing a 6-O-methylerythromycin A derivative represented by the formula: wherein R1 is:a 2-alkenyl group having 3 to 15 carbon atoms, a benzyl group, or a benzyl group substitued by 1 to 3 of a chlorine atom, an alkoxy group having 1 to 4 carbon atoms, a nitro group or an alkoxycarbonyl group having 2 to 6 carbon atoms, and R2 and R3 are trimethylsilyl, which comprises reacting, in any desired sequence, erythromycin A 9-oxime with a compound of formula R1â€”X (wherein R1 is as defined above, and X is a halogen atom) and with a substituted silylating agent having R2 group to give a compound represented by the formula; (wherein R1, R2 and R3 are as defined above), and then reacting said compound of formula II with a methylating agent selected from the group consisting of methyl bromide, methyl iodide, dimethyl sulfate, methyl p-toluene sulfonate and methyl methane sulfonate, the amount said methylating agent being 1-3 molar equivalents of said compound of formula II, said trimethylsilyl group (R2) protecting the 2â€² hydroxyl group against methylation and the 3â€²-dimethylamino group from being quaternized with the methylating agent.