Synthesis
Indazole-3-carboxylic acid (10 g, 61.7 mmol) was used as a raw material, which was dissolved in DMF (100 mL), and carbonyldiimidazole (11 g, 67.84 mmol) was slowly added at room temperature, and gas was observed to be released during the reaction for 15 min. Subsequently, the reaction mixture was heated to 65 °C and maintained for 2 hours. After completion of the reaction, the mixture was cooled to room temperature, N,O-dimethylhydroxylamine hydrochloride (4.14 g, 67.8 mmol) was added and the mixture was again heated to 65 °C and reacted overnight. At the end of the reaction, the reaction mixture was cooled, the reaction was quenched with water, extracted with dichloromethane (CH2Cl2) and the organic phase was washed with water. The organic phases were combined and concentrated after drying to afford the target product N-methoxy-N-methyl-1H-indazole-3-carboxamide (10.3 g, 81.4% yield).
References
[1] Tetrahedron Letters, 2007, vol. 48, # 14, p. 2457 - 2460
[2] Tetrahedron, 2007, vol. 63, # 2, p. 419 - 428
[3] Patent: WO2008/71451, 2008, A1. Location in patent: Page/Page column 50
[4] Patent: WO2013/40215, 2013, A1. Location in patent: Paragraph 00334
[5] Patent: US2013/267495, 2013, A1. Location in patent: Paragraph 0409
