Hydrogen Peroxide → 3-Cyano-7,8-difluoro-1-methyl-4-oxo-1,4-dihydrobenzo[b][1,8]naphthyridine

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A solution of 0.47 g of potassium iodide in 5 cm3 of water is added with stirring at approximately 20° C. to a suspension of 8.6 g of 3-cyano-7,8-difluoro-1-methyl-4-oxo-1,2,3,4-tetrahydrobenzo[b][1,8]naphthyridine in 350 cm3 of ethanol. The suspension is heated to 77° C., and 4 cm3 of 33% by weight hydrogen peroxide are added in the course of 10 minutes at this temperature. The reaction mixture is kept refluxing for a further 30 minutes and is then cooled to approximately 20° C. 10 cm3 of 1N sodium thiosulphate solution are added in the course of 5 minutes at this temperature. The precipitate obtained is drained at approximately 20° C. and washed with twice 20 cm3 of water. The wet product obtained is dried under reduced pressure (20 kPa) at approximately 50° C. 8 g of 3-cyano-7,8-difluoro-1-methyl-4-oxo-1,4-dihydrobenzo[b]-[1,8]naphthyridine are obtained in the form of a light yellow solid, melting point 380° C.

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