Synthesis
In a 3000 L reactor, 438 kg of p-iodoaniline, 190 kg of 2-hydroxypyridine, 58 kg of 8-hydroxyquinoline, 207 kg of potassium carbonate and 1500 kg of N,N-dimethylformamide (DMF) were added and the system was started with stirring under nitrogen protection. The reaction mixture was heated to reflux temperature and kept reacting overnight. The progress of the reaction was monitored by chromatographic analysis until the reaction was complete. Upon completion of the reaction, the resulting potassium iodide was removed by filtration. Subsequently, some DMF was recovered by distillation under reduced pressure and filtered after the system was cooled to 50 °C to obtain 1-(4-aminophenyl)-1H-pyridin-2-one crude. The crude product was dissolved in 740 kg of ethanol, heated until completely dissolved and then added 55 kg of activated carbon for decolorization. The decolorized solution was thermally filtered and the filtrate was crystallized by cooling. The crystallized product was collected by filtration, dried and packed to finally obtain 1-(4-aminophenyl)-1H-pyridin-2-one with 95% yield and 99% purity.
References
[1] Patent: CN107382836, 2017, A. Location in patent: Paragraph 0021; 0022
[2] Patent: US2015/158865, 2015, A1. Location in patent: Paragraph 1127; 1128
[3] European Journal of Medicinal Chemistry, 2017, vol. 125, p. 411 - 422
[4] Patent: WO2014/139145, 2014, A1. Location in patent: Page/Page column 37
[5] Patent: WO2014/139465, 2014, A1. Location in patent: Page/Page column 38
