With hydrogenchloride; iron In water; isopropyl alcohol at 10 - 20℃; for 2 h;
To a solution of 13.1 (17.5g, 84.l4mmol, 1.0 eq) in Isopropyl alcohol (525mL) was added Iron powder (23.6g, 420 mmol, 5.Oeq) and stirred. To this mixture was added 6N HC1 (7OmL) dropwise at 10°C. The reaction mixture was stirred at r.t. for 2h. After completion of reaction saturated NaHCO3 solution was added to pH 8. Reaction mixture was filtered through celite. Filtrate was extracted with ethyl acetate. Organic layers were combined, washed with brine, dried over Na2504 and concentrated in vacuo to obtain 11.2 (14g, 93.47percent). MS(ES): m/z 178 [M+H]t
89%
With iron; ammonium chloride In water; isopropyl alcohol at 70℃; for 2 h;
b) 4,6-Dichloropyridine-2,3-diamine (A92) To a stirred suspension of 4,6-dichloro-3-nitropyridin-2-amine A91 (0.51 g, 2.5 mmol) in a mixture of water (11 mL) and propan-2-ol (22 mL) was added iron powder (0.68 g, 12 mmol followed by NH4CI (0.64 g, 12.2 mmol) at room temperature and the mixture was then heated to 70 °C for 2 hours. The cooled reaction mixture was filtered through celite and washed with EtOAc (150 mL). The resulting solution was washed with saturated aqueous NaHC03, brine, dried over Na2S04, filtered and evaporated under reduced pressure then dried to give the title compound as light brown crystals (0.39 g, 89percent); H NMR (400 MHz, CDCIs) 5 6.76 (s, 1 H), 4.44 (s, 2H), 3.56 (s, 2H).LCMS-A: rt 5.53 min, m/z (positive ion)178.1 [M+H]+.
A solution of of 4.81 g (27 mmol) <strong>[24484-99-9]4,6-dichloro-pyridine-2,3-diamine</strong> (synthesis described in J. E. Schelling, C. A. Salemink, Rec. Trav. Chim. Pays-Bas 91 , 650 [1972]) in 50 ml THF was treated with 5.22 g (27 mmol) of a 30percent solution of glyoxal in water and the mixture was stirred for 3 days at room temperature. The reaction mixture was evaporated and the residue was partitioned between dichloromethane and diluted sodium carbonate solution. The organic phase was dried over sodium sulfate and evaporated. The residue was chromatographed on a silica gel column with cyclohexane/ethyl acetate as eluent yielding 6,8-dichloro- pyrido[2,3-b]pyrazine as off-white fine needles; HPLC/MS (B): 1.93 min, [M+H] 200. 1H NMR (400 MHz, CDCI3) delta = 9.16 (d, J=1.7, 1 H), 9.05 (d, J=1.7, 1H), 7.89 (s, 1 H).
Chemistry
Pharmaceutical Intermediates
Inhibitors/Agonists
Material Science
Life Science
For Research Only
80K+ Compounds
Competitive Price
1-2 Day Shipping
