General Papers ARKIVOC 2005 (i) 137-142 Conclusions We have synthesized a series of 2-amino-3-cyanopyridine derivatives by one-pot method under microwave irradiation and solvent-free conditions, thus providing a facile, rapid, efficient and environmentally friendly method. Experimental Section General Procedures. Melting points were determined in a capillary tube and were uncorrected. The 1H NMR spectra were recorded on a DPX 400 MHz spectrometer with TMS as internal standard. The IR spectra were obtained with SE-1730 instrument as potassium bromide pellets. Elemental analyses were determined by using a Perkin-Elmer 240c elemental analysis instrument. Typical procedure for the preparation of 2-amino-3-cyanopyridines The preparation of 4: A dry flask (25 mL) charged with aldehyde (2 mmol), methyl ketone (2 mmol), malononitrile (2 mmol) and ammonium acetate (3 mmol) was placed in a microwave oven. The flask was then connected with refluxing equipment. After being irradiated for 7-9 min, the reaction mixture was washed with ethanol (2 mL). The crude products were purified by recrystallization from 95% ethanol to afford pure products. 4-(4-Chlorophenyl)-6-(4-methoxyphenyl)-2-amino-3-cyanopyridine (4a). Colour- less crystals (0.557g, 83%); mp 195–196 °C. IR (KBr): . 3454 and 3361 (NH2), 3232 (ArH), 2201 (CN) cm-1.1H NMR (400MHz, DMSO-d6): d 8.12 (2H, d, J=8.4 Hz, ArH), 7.70 (2H, d, J=8.4 Hz, ArH), 7.63 (2H, d, J=8.4 Hz, ArH), 7.23 (1H,s, PyrH), 7.04 (2H, d, J=8.4 Hz, ArH), 6.99 (2H, s, NH2), 3.83 (3H, s, OCH3). Anal. Calcd for C19H14ClN3O: C, 67.96; H, 4.20; N, 12.51. Found: C, 67.58; H, 4.58; N, 12.20. 4-(4-Methoxyphenyl)-6-(4-methoxyphenyl)-2-amino-3-cyanopyridine (4b). Colourless crystals (0.530g, 80%); mp 159–160 °C. IR (KBr): . 3458 and 3361 (NH2), 3232 (ArH), 2201 (CN) cm-1. 1H NMR (400MHz, DMSO-d6): d 8.10 (2H, d, J=8.4 Hz, ArH), 7.64 (2H, d, J=8.4 Hz, ArH), 7.19 (1H, s, CH), 7.11 (2H, d, J=8.4 Hz, ArH), 7.03 (2H, d, J=8.4 Hz, ArH), 6.88 (2H, s, NH2), 3.84 (3H, s, OCH3), 3.82 (3H, s, OCH3). Anal. Calcd for C20H17N3O2: C, 72.49; H, 5.17; N, 12.68. Found: C, 72.73; H, 4.85; N, 12.94. 4-(4-Methoxyphenyl)-6-(2,4-dichlorophenyl)-2-amino-3-cyanopyridine (4c). Colourless crystals (0.555g, 75%); mp 184–185 °C. IR (KBr): . 3467 and 3364 (NH2), 3309 (ArH), 2201 (CN) cm-1. 1H NMR (400MHz, DMSO-d6): d 7.08-7.75 (9H, m, ArH and NH2), 6.19 (1H, s, CH). Anal. Calcd for C19H13Cl2N3O: C, 61.64; H, 3.54; N, 11.35. Found: C, 671.25; H, 3.90; N, 11.03. 4-(4-Methoxyphenyl)-6-phenyl-2-amino-3-cyanopyridine (4d). Colourless crystals (0.512g, 85%); mp 180–182 °C. IR (KBr): . 3462 and 3307 (NH2), 3184 (ArH), 2201 (CN) cm-1. 1H NMR (400MHz, DMSO-d6): d 8.11-8.12 (2H, m, ArH), 7.66 (2H, d, J=8.4 Hz, ArH), 7.48-7.49 (3H, m, ArH), 7.25 (1H, s, CH), 7.11 (2H, d, J=8.4 Hz, ArH), 6.96 (2H, s, NH2), 3.85 (3H, s, OCH3). Anal. ISSN 1424-6376 Page 140 ©ARKAT USA, Inc
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