Analogifremgangsmåde til fremstilling af imidazolderivater af rifamycin SV eller af 25-desacetylrifamycin SV

1388880 3-Imidazole derivatives of rifamycin SV GRUPPO LEPETIT SpA 28 Dec 1972 [19 Jan 1972] 59832/72 Heading C2C Novel 3-imidazole derivatives of rifamycin SV having the general Formula (I) and the corresponding 25-desacetyl and 16, 17, 18, 19, 28, 29-hexahydro derivatives, wherein R is hydrogen, C 1-6 alkyl, phenyl or phenyl- C 1-6 alkyl; and R 1 and R 2 together represent a carbocyclic residue forming with the double bond of the adjacent imidazol moiety a benzene ring; a mono- or poly-substituted benzene ring wherein the substituents are selected from C 1-6 alkyl, C 1-6 alkoxy, halo, carbalkoxy, carboxy, sulpho, sulphamoyl, nitro, trifluoromethyl, carbamyl, mono- and di-C 1-6 alkylcarbamyl and methylenedioxy; or a substituted or unsubstituted polynuclear aromatic radical composed of 2 or 3 fused rings each of 5-6 carbon atoms, are prepared by reacting 3-formylrifamycin SV or a 25-desacetyl or 16, 17, 18, 19, 28, 29-hexahydro derivative thereof, with an orthodiamine of formula wherein R, R 1 and R 2 are as defined above, and then oxidizing the product with air, a cupric salt, mercuric oxide, manganese dioxide, isoamyl nitrite, potassium ferricyanide or lead tetraacetate, and if the rifamycin moiety in the obtained compound is in the quinone form, reducing it to the corresponding hydroquinone with aqueous ascorbic acid. The compounds (I) have antibacterial, antiviral and anti-cancer activity and may be admixed with a pharmaceutical carrier to provide pharmaceutical compositions having such activity.