3-Pyridinecarboxaldehyde, 2-amino- → 2-(2-Amino-3-pyridyl)-2,3-dihydro-1,3-benzoxazole-7-carbonitrile

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Reaktionsschritte

A mixture of 2-aminopyridine-3-carbaldehyde (300 mg) and 3-amino-2-hydroxy-benzonitrile (330 mg) in methanol (10 ml) was stirred at 50° C. for overnight. The resulting suspension was concentrated to dryness to afford 2-(2-amino-3-pyridyl)-2,3-dihydro-1,3-benzoxazole-7-carbonitrile (585 mg) as a pale brown solid, which was used without further purification. 2-(2-amino-3-pyridyl)-2,3-dihydro-1,3-benzoxazole-7-carbonitrile (585 mg) and manganese dioxide (4269 mg) in dichloromethane (50 ml) was stirred at room temperature for 2 hours. The reaction mixture was filtered and the filtrate was evaporated. The residue was purified by preparative HPLC using a Waters X-Terra reverse-phase column (5 micron silica, 19 mm diameter, 100 mm length) and decreasingly polar mixtures of water (containing 0.2% ammonium carbonate) and acetonitrile as eluent. The fractions were evaporated to dryness to afford 2-(2-amino-3-pyridyl)-1,3-benzoxazole-7-carbonitrile (59.0 mg) as a pale brown solid. NMR Spectrum: (DMSOd6) 6.82 (dd, 1H), 7.59 (dd, 1H), 7.67 (bs, 2H), 7.93 (dd, 1H), 8.18 (dd, 1H), 8.28 (dd, 1H), 8.32 (dd, 1H); Mass spectrum: M+H+ 237;

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