Sodium Carbonate → 4-Keto-9-methylphenazine

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Reaction Steps

2 g (0.011 mol) of 9-methylphenazinium methylsulphate are dissolved in 2 l of distilled water and then exposed for 24 hours to UV-radiation (from a source having a power 1.5 kW, at a distance of 30-40 cm) at the temperature of 40° C. in a closed quartz flask, then added with a 0.1M solution of sodium carbonate to the pH of 9.0. Then the irradiation is continued for additional 4 hours. The solution is filtered, added with 40 ml of a 10% solution of sodium carbonate and extracted four times with 200 ml portions of chloroform. The extracts are combined, dried with potassium carbonate and evaporated to the volume of 70 ml, then 250 ml of hot hexane are added and the mixture is cooled. The formed precipitate is filtered off, washed with 200 ml of hexane, recrystallized from 50 ml of water to give 0.83 g of 4-keto-9-methylphenazine (61%) in the form of blue crystals melting at 133°-135° C.

Provenance & Evidence