Hydrochloric Acid → 9H-Cyclopenta[1,2-b:4,3-b']dipyridin-9-one

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Reaction Steps

To a solution of 200 ml of 10% sodium hydroxide was added 10 g (47 mmole) of 4,7-phenanthrolin-5,6-quinone. This was heated in a water bath at 70°-80° with magnetic stirring for 2 hours. Then the reaction was cooled in an ice bath and acidified with concentrated hydrochloric acid to pH 4-5, keeping the mixture below 20°. The precipitate of side product, 5,6-dihydroxy-4,7-phenanthroline was filtered off and the filtrate was extracted with 5×50 ml of chloroform. After drying with sodium sulfate, the solvent was evaporated, yielding 2.6 g of 1,8-diazafluoren-9-one, m.p. 233°-234.5°.

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