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With hydrogenchloride; iron In ethanol; water at 80 - 100℃;
General procedure: The appropriate nitro compound was dissolved in an ethanol/water mixture (5:1) (about 2-3M), and concentrated hydrochloric acid (0.5-1 eq.) and iron powder (3-8 eq.) were added. The reaction mixture was heated at 80 to 100° C. until the reaction had gone to completion (about 1 to 6 h). The hot reaction mixture was filtered through kieselguhr. The filtercake was washed with methanol and the filtrate was concentrated under reduced pressure. The crude product was then purified either by means of normal phase chromatography (eluent: cyclohexane/ethyl acetate mixtures or dichloromethane/methanol mixtures) or preparative RP-HPLC (water/acetonitrile gradient or water/methanol gradient); According to General Method 9A, the crude product (about 23.8 mmol) 5-nitropyridine-2-carboxamide was reacted. The product obtained was purified by means of normal phase chromatography (eluent: dichloromethane/ methanol (9:1) with 1.5percent concentrated ammonia). Yield:1.40 g (42percent of theory) LC/MS [Method 5]: Rt=0.50 mm; MS (ESIpos):mlz=138 (M+H), ‘H-NMR (400 MHz, DMSO-d5): ö [ppm]=7.89 (d, 1H), 7.70 (d, 1H), 7.64 (bs, 1H), 7.11 (bs, 1H), 6.95 (dd, 1H),5.90 (s, 2H).
With hydrogenchloride; iron; In ethanol; water; at 80 - 100℃;
General procedure: The appropriate nitro compound was dissolved in an ethanol/water mixture (5:1) (about 2-3M), and concentrated hydrochloric acid (0.5-1 eq.) and iron powder (3-8 eq.) were added. The reaction mixture was heated at 80 to 100 C. until the reaction had gone to completion (about 1 to 6 h). The hot reaction mixture was filtered through kieselguhr. The filtercake was washed with methanol and the filtrate was concentrated under reduced pressure. The crude product was then purified either by means of normal phase chromatography (eluent: cyclohexane/ethyl acetate mixtures or dichloromethane/methanol mixtures) or preparative RP-HPLC (water/acetonitrile gradient or water/methanol gradient); According to General Method 9A, the crude product (about 23.8 mmol) 5-nitropyridine-2-carboxamide was reacted. The product obtained was purified by means of normal phase chromatography (eluent: dichloromethane/ methanol (9:1) with 1.5% concentrated ammonia). Yield:1.40 g (42% of theory) LC/MS [Method 5]: Rt=0.50 mm; MS (ESIpos):mlz=138 (M+H), ?H-NMR (400 MHz, DMSO-d5): oe [ppm]=7.89 (d, 1H), 7.70 (d, 1H), 7.64 (bs, 1H), 7.11 (bs, 1H), 6.95 (dd, 1H),5.90 (s, 2H).
With pyridine; ammonium chloride; 2,4,6-tripropyl-1,3,5,2,4,6-trioxatriphosphinane-2,4,6-trioxide; In ethyl acetate;
General procedure: A solution of the appropriate carboxylic acidcarboxylic acid hydrochloride (1 eq.) and the appropriate amine or amine hydrochloride (1.1-1.9 eq.) in pyridine (about 0.1 M) was heated to 60° C., and T3P (50percent in ethyl acetate, 1.5-15 eq.) was added dropwise. Alternatively, T3P was added at RT and the mixture was then stirred at RTheated to 50 to 90° C. After 1 to 20 h, the reaction mixture was cooled to RT and either purified directly by meanspreparative RP-HPLC (water-acetonitrile gradient or water- methanol gradient) or admixed with water and ethyl acetate. The aqueous phase was extracted with ethyl acetate.combined organic phases were washed with aqueous buffer solution (pH=5), with saturated aqueous sodium hydrogen- carbonate solution and with saturated aqueous sodium chloride solution, dried over sodium sulphate and concentrated under reduced pressure. The crude product was then optionally purified either by means of normal phase chromatography (eluent: cyclohexane/ethyl acetate mixtures or dichloromethane/methanol mixtures) or preparative RP-HPLC(water/acetonitrile gradient or water/methanol gradient); According to General Method 58, 4.00 g (23.8 mmol) of <strong>[30651-24-2]5-nitropyridine-2-carboxylic acid</strong> and 1.91 g (35.7 mmol, 1 .5 eq.) of ammonium chloride were reacted. After workup, the crude product was used for the next stage without thrther purification. LC/MS [Method 1]: R=0.39 mm; MS (ESIpos):mlz=168 (M+H),
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