143141-23-5

4.2.4 Synthesis of 1-(phenylsulfonyl)-1H-pyrrolo[2,3-b]pyridine (5) In a dry and nitrogen purged round bottom flask, 1H-pyrrolo[2,3-b]pyridine (1.01 g, 8.58 mmol), tetrabutylammonium bromide (81 mg, 0.25 mmol), finely ground sodium hydroxide (1.02 g, 25.41 mmol) and dichloromethane (20 mL) were added. The mixture was cooled to 0 °C in an ice bath and stirred, followed by the slow dropwise addition of benzenesulfonyl chloride (1.35 mL, 10.59 mmol). The reaction mixture was gradually warmed to room temperature and stirred continuously at this temperature for 1 hour. Upon completion of the reaction, water (20 mL) was added for hydrolysis and then extracted twice with dichloromethane. The organic layers were combined, washed with saturated sodium chloride solution, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure to give 2.38 g of a beige solid. The crude product was purified by silica gel column chromatography (eluent: cyclohexane/ethyl acetate=7:3) to give 2.17 g of white solid target product in 99% yield. 1H NMR (300 MHz, CDCl3) δ (ppm): 8.45 (dd, J = 1.5, 4.8 Hz, 1H), 8.20 (d, J = 7.5 Hz, 2H), 7.86 (dd, J = 1.5, 7.8 Hz, 1H), 7.73 (d, J = 4.0 Hz, 1H), 7.57 (dd, J = 7.4 Hz, 1H ), 7.52-7.47 (m, 2H), 7.19 (dd, J = 4.8, 7.8 Hz, 1H), 6.61 (d, J = 4.0 Hz, 1H). 13C NMR (75 MHz, CDCl3) δ (ppm): 144.7 (2C), 138.3, 134.1, 129.9, 129.1 (2C), 128.0 (2C), 126.5, 123.0, 119.0, 105.5.

[1] European Journal of Medicinal Chemistry, 2016, vol. 108, p. 701 - 719
[2] Patent: WO2016/114816, 2016, A1. Location in patent: Paragraph 0290
[3] Organic Letters, 2015, vol. 17, # 19, p. 4710 - 4713
[4] Tetrahedron, 1997, vol. 53, # 10, p. 3637 - 3648
[5] Patent: WO2006/50076, 2006, A1. Location in patent: Page/Page column 61