Methane → 9-Iodo-3-methyl-7-oxo-2,3-dihydro-7H-[1,3,4]oxadiazino[6,5,4-ij]quinoline-6-carboxylic acid

関与物質

反応条件

反応手順

Ethyl 2-(2,3-difluoro-5-iodobenzoyl)-3-(2-formyl-2-methylhydrazino)prop-2-enoate (Preparation 30, 1.02 g) in 8 mL of water is treated with KOH pellets (0.410 g) and the reaction mixture is heated in an oil bath, under a nitrogen atmosphere, at 105° C. for 1.75 h while volatiles were condensed into a Dean-Stark trap. At this time, the Dean-Stark trap was removed, 1 mL of an aqueous solution of KOH (0.956 g) is added to the mixture, and heating is continued at 105° C. for 4 days. The mixture is cooled to room temperature, treated with formic acid (1.68 g), and is warmed to 45-50° C. A 37% aqueous formaldehyde (0.396 g) is added and the mixture is heated at 70° C. for 30 minutes. The resulting slurry is cooled in an ice bath at 0-5° C., reacted with 29% aqueous ammonium hydroxide (1.46 mL), and allowed to warm to room temperature where it is stirred for 35-40 minutes. Charcoal (44 mg) is added to the mixture which is stirred for 30 minutes and filtered through a pad of solka-floc rinsing with water. The filtrate is diluted with saturated brine and a mixture of chloroform/methanol (95/5) and filtered through a pad of solka-floc. The organic layer is separated, dried with anhydrous sodium sulfate, and concentrated at reduced pressure to obtain 252 mg (28%) of the title compound. Physical characteristics: MS (ESI+) m/z 373 (M+H)+.

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