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With hydrazine hydrate In methanol at 60℃; for 4 h;
The 2,3-dicarbonylindolone-6-carboxylic acid was dissolved in 500 ml of methanol, and hydrazine hydrate (60 ml) was slowly added dropwise, and the temperature was raised to 60 ° C with stirring. After 4 hours of reaction, the methanol was distilled off, added with dilute hydrochloric acid, adjusted to pH 2-3, extracted with DCM (500ml) three times. The organic phases were combined and evaporated to dryness. The solid was filtered and the 2-carbonylindolone-6- Carboxylic acid 45 g, yield: 69percent.
Reference:
[1] Patent: CN106854173, 2017, A, . Location in patent: Paragraph 0020; 0027-0029
With hydrazine hydrate; In methanol; at 60℃; for 4h;
The 2,3-dicarbonylindolone-6-carboxylic acid was dissolved in 500 ml of methanol, and hydrazine hydrate (60 ml) was slowly added dropwise, and the temperature was raised to 60 C with stirring. After 4 hours of reaction, the methanol was distilled off, added with dilute hydrochloric acid, adjusted to pH 2-3, extracted with DCM (500ml) three times. The organic phases were combined and evaporated to dryness. The solid was filtered and the 2-carbonylindolone-6- Carboxylic acid 45 g, yield: 69%.