GB1260996A - A process for the manufacture of phenazine derivatives - Google Patents

Abstract

1,260,996. Preparing 1-hydroxy-6-alkoxyphenazine 5,10-dioxides. F. HOFFMANN-LA ROCHE & CO. A.G. 2 April, 1970 [22 April, 1969], No. 15635/70. Headings C2A and C2C. The antibiotic myxin, and other 1-hydroxy-6- alkoxy-phenazine 5,10-dioxides in which the alkoxy group has 1 to 7 carbon atoms, are prepared by reacting a mono-alkali metal salt of 1,6-dihydroxyphenazine 5,10-dioxide iodinin with an alkylating agent in an aprotic polar organic solvent for the salt and recovering the 6- alkoxy compound. The preferred solvent is hexamethylphosphoric triamide, or dimethylformamide or dimethylsulphoxide may be used. The alkali metal salt (e.g. Na or K) may be prepared in situ in the aprotic solvent by reacting iodinin with an equimolar amount of alkali metal alkoxide therein. Alternatively it is prepared by treating iodinin with an excess of aqueous alkali metal hydroxide, filtering off the required salt and drying it. Alkylating agents may be dialkyl sulphates, alkyl iodides, or alkyl tosylates. The 6-alkoxy compound is recovered from the aprotic solvent by addition of ice-water or a non-solvent such as chloroform and is purified e.g. by chromatography on silica gel or alumina. 1-Hydroxy-6-(3-methylbutoxy)-phenazine 5,10- dioxide is prepared by alkylating the potassium salt of iodinin with 1-bromo-3-methylbutane in hexamethylphosphoric triamide. Reference has been directed by the Comptroller to Specification 1,177,697.