Selenium Dioxide → HCID 12875021, compound

Participants

Reaction Steps

A mixture of 30.4 g of ethyl 1,4-dihydro-6-ethoxy-1-ethyl-7-methyl-4-oxo-1,8-naphthyridine-3-carboxylate (Compound VIII where R1 =R2 =R3 =C2H5) and 100 ml of sulfolane was stirred at 140°-145° C. and 22 g of selenium dioxide in limited amounts was added thereto. After reacting the mixture under the same conditions for 5 hours and then allowing it to cool, chloroform was added thereto. The insoluble materials were removed by filtration. The filtrate was washed successively with 3% sodium carbonate solution, water, dried over anhydrous sodium sulfate and evaporated. To the residue was added isopropanol and the precipitated crystals were collected by filtration to obtain 22.0 g of ethyl 1,4-dihydro-6-ethoxy-1-ethyl-7-formyl-4-oxo-1,8-naphthyridine-3-carboxylate, m.p. 169°-170° C.

Provenance & Evidence