[Synthesis]
A solution of 1-fluoro-2-nitrobenzene (34.5 g, 244 mmol) and 2-amino-3-cyano-5-methylthiophene (33.1 g, 240 mmol) in anhydrous THF (160 mL) was added slowly and dropwise to a vigorously stirred anhydrous tetrahydrofuran (THF, 100 mL) suspension of sodium hydride (NaH, 13.5 g, 60% dispersed in mineral oil, 336 mmol), cooled in an ice bath, and under nitrogen protection. mmol) in a solution of anhydrous THF (160 mL). After dropwise addition, the reaction mixture was stirred at room temperature for 10 hours. Subsequently, additional sodium hydride (NaH, 1.53 g, 95%, 72 mmol) was slowly added to the reaction mixture and stirring was continued for 8 hours at room temperature. Upon completion of the reaction, the mixture was poured into crushed ice and the pH was adjusted to 8 with saturated ammonium chloride (NH4Cl) solution. the precipitate was collected by filtration and dried to give the crude product. The crude product was purified by silica gel column chromatography (eluent: 10% ethyl acetate/hexane) to afford 2-(2-nitroanilino)-3-cyano-5-methylthiophene (47.9 g, 77% yield) as a dark solid. Thin layer chromatography (TLC) Rf value was 0.62 (25% ethyl acetate/hexane). The melting point is 105-107°C. Nuclear magnetic resonance hydrogen spectrum (1H NMR, CDCl3): δ 2.47 (d, J = 1.0 Hz, 3H, CH3), 6.78 (q, J = 1.0 Hz, 1H, Ar-H), 6.95 (ddd, J = 1.0, 7.0, 8.5 Hz, 1H, Ph-H), 7.18 (dd, J = 1.0, 8.5 Hz, 1H, Ph-H) , 7.50 (dd, J = 1.5, 7.0, 8.5 Hz, 1H, Ph-H), 8.24 (dd, J = 1.5, 8.5 Hz, 1H, Ph-H), 9.61 (s, 1H, NH). Mass spectrum (MS, ESI): m/z 258 ([M-H]? , 100%). |
[References]
[1] Bioorganic and Medicinal Chemistry Letters, 2013, vol. 23, # 7, p. 1953 - 1956
[2] Patent: US2010/266711, 2010, A1. Location in patent: Page/Page column 14
[3] Patent: WO2008/50341, 2008, A2. Location in patent: Page/Page column 33
[4] Patent: WO2004/94390, 2004, A1. Location in patent: Page 13-14
[5] Russian Journal of Bioorganic Chemistry, 2005, vol. 31, # 4, p. 378 - 382 |