[Synthesis]
The general procedure for the synthesis of 3-(2-pyridyl)aniline from phenyl-2-pyridyl ketoxime was as follows: phenyl(2-pyridyl)ketoxime (5.0 g, 25.2 mmol) was dissolved in ice-cold mixed solvent of acetic acid (50 mL) and ethanol (100 mL). Under stirring, zinc powder (50 g) was added in batches of 2 g. After addition, the reaction mixture was stirred at room temperature for 24 hours. After completion of the reaction, the unreacted zinc powder was removed by filtration and washed well with ethanol. The filtrate and washings were combined and concentrated under reduced pressure. Several 10 mL of water were added to the concentrate and the acetic acid was removed by evaporation. The pH of the mixture was adjusted to about 12 with aqueous KOH and then extracted with diethyl ether (3 x 50 mL). The organic phases were combined, dried over anhydrous Na2SO4, and the solvent was evaporated under reduced pressure to afford the target product 3-(2-pyridyl)aniline in a yield of 4.5 g (96.8% yield). The product was subjected to IR, 1H NMR, 13C NMR and elemental analysis to confirm the structure.IR (KBr, cm-1): 3445(b), 3307(b), 3255(s), 3180(s), 3101(w), 1630(s), 1604(s), 1549(w), 1519(s), 1477(s), 1466(s), 1441(s), 1363(s). 1441(s), 1363(s), 1282(s), 1252(s), 1211(w), 1161(w), 1097(s), 1038(s), 766(s), 658(w), 640(w), 543(s).1H NMR (400 MHz, CDCl3): δ 8.53 (1H, d, J=4.8Hz ), 7.56(1H, t, J=7.6Hz), 7.39(1H, d, J=8.0Hz), 7.30(1H, t, J=7.6Hz), 7.24(1H, t, J=6.4Hz), 7.19(1H, d, J=6.4Hz), 7.10(1H, t, J=6.2Hz), 5.21(1H, s), 5.21(1H, s). 2.75 (2H, s, NH2).13C NMR (100 MHz, CDCl3): δ 158.6, 154.2, 149.6, 136.7, 131.0, 129.2, 128.7, 128.5, 123.1, 56.2. Elemental analysis (C12H12N2) calculated values: C, 78.23; H, 6.57; N Calculated values for elemental analysis (C12H12N2): C, 78.23; H, 6.57; N, 15.21. Measured values: C, 77.64; H, 5.98; N, 15.13%. |