[Synthesis]
General procedure for the synthesis of 2,5-difluoro-4-iodoaniline from 2,5-difluoroaniline: 2,5-difluoroaniline (0.5 g, 3.9 mmol), NaHCO3 (0.8 g, 9.8 mmol), I2 (2.5 g, 9.8 mmol), and H2O (50 mL) were mixed and stirred at room temperature. After 2 h of reaction, Na2SO3 (1 g, 8 mmol) was added, followed by extraction of the reaction mixture with CH2Cl2 (2 × 50 mL). The organic layers were combined, washed with H2O (50 mL), dried (MgSO4) and purified by fast chromatography through an Al2O3 column. The solvent was evaporated under vacuum to give the brown solid product 2,5-difluoro-4-iodoaniline (0.9 g, 91% yield). The 1H and 13C NMR spectra of the product were consistent with literature data. IR spectra (KBr, cm-1 ): 3464, 3379, 3042, 2926, 2855, 1632, 1501, 1414, 1323, 1298, 1234, 1184, 1167, 864, 837, 795, 733, 596, 444.1H NMR (500.13 MHz, CDCl3): δ= 7.27 (dd, 1H, JH3,F2=9.9, JH3,F5=5.6 Hz, H3), 6.52 (d, 1H, JH6,F5=8.7, JH6,F2=7.7 Hz, H6), 3.91 (br s, 2H, NH2).13C NMR (125.76 MHz, CDCl3): δ=158.0 (d 1JC5,F5=239.1 Hz, C5), 147.4 (d, 1JC2,F2=239.6 Hz, C2), 135.7 (dd, 2JC1,F2=14.7, 3JC1,F5=10.6 Hz, C1), 123.8 (dd, 2JC3,F2=22.8, 3JC3,F5=3.5 Hz, C3). 102.7 (dd, 2JC6,F5=29.9, 3JC6,F2=3.7 Hz, C6), 62.8 (dd, 2JC4,F5=29.1, 3JC4,F2=8.1 Hz, C4).19F NMR (282.37 MHz, CDCl3): δ=-101.5 (dd, 1F, JF5,F2=13.4 JF5,H6=8.7, JF5,H3=5.6 Hz, F5), -140.0 (ddd, 1F, JF2,F5=13.4, JF2,H3=9.9, JF2,H6=7.7 Hz, F2). High-resolution mass spectrum (EI): m/z calculated value 254.9351 [M]+, measured value 254.9356. |