| 摘要 |
Pyridoimidazorifamycins of the formula <IMAGE> where R is hydrogen or acetyl, R1 and R2 independently denote hydrogen, (C1-4)-alkyl, benzyloxy, mono- or di-(C1- 3)-alkylamino-(C1-4)-alkyl, (C1-3)-alkoxy-(C-4)-alkyl, hydroxymethyl, hydroxy-(C2-4)-alkyl, cyano, halogen, nitro, mercapto, (C1-4)-alkylthio, phenylthio, carbamoyl, or mono- or di-(C1-4)-alkylcarbamoyl, or R1 and R2, together with two neighbouring carbon atoms in the pyridine nucleus, form a benzene ring which is optionally substituted by 1 or 2 methyl or ethyl groups, are prepared by one mol equivalent of rifamycin B being reacted with from about 1 to about 9 mol equivalents of a 2-aminopyridine in the presence of a suitable oxidizing agent. Commercially available starting materials are used in the process.
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