反应详情

温度

40 °C

An ice-cold suspension of the hydrochloride salt of nicotinoyl chloride (5 grams (g), 28 millimoles (mmol)) in dichloroethane (DCE, 150 milliliters (mL)) was treated with glycine methyl ester hydrochloride (3.7 g, 29 mmol) in portions, followed by dropwise addition of triethylamine (Et3N, 15.6 mL, 0.111 moles (mol)) via syringe. The reaction mixture was allowed to come to room temperature under nitrogen over 14 hours (h), washed with water (2×100 mL), brine (100 mL), dried over magnesium sulfate (MgSO4) and purified by silica gel chromatography (ethyl acetate/hexanes gradient) to yield an orange solid (1.8 g, 33%). The aqueous washings of the crude reaction mixture were saturated with sodium chloride (NaCl), extracted with dichloromethane (CH2Cl2) and purified by silica gel chromatography (ethyl acetate/hexanes gradient) to yield a yellow solid (1.6 g, 29%; total yield 3.4 g, 62%): mp 66-68° C.; 1H NMR (300 MHz, CDCl3) δ 9.04 (d, J=2.2 Hz, 1H), 8.76 (dd, J=4.8, 1.5 Hz, 1H), 8.15 (dt, J=8.1, 1.8 Hz, 1H), 7.42 (dd, J=8.1, 4.8 Hz, 1H), 6.84 (br s, 1H), 4.28 (d, J=5.2 Hz, 2H), 3.82 (s, 3H); ESIMS m/z 195 (M+1). Method B A mixture of nicotinic acid (10 g, 81 mmol), p-toluenesulfonyl chloride (17 g, 89 mmol), benzyltriethylammonium chloride (1.85 g, 8.1 mmol), and potassium carbonate (K2CO3, 44.9 g, 320 mmol) in chloroform (CHCl3, 500 mL) was stirred mechanically at 40° C. for 1 h. Glycine methyl ester hydrochloride (10.2 g, 81 mmol) and K2CO3 (11.2 g, 80 mmol) were then added and stirred at 50° C. for 90 minutes (min). The reaction mixture was filtered through Celite® and the filtrate was concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (2% methanol/ethyl acetate) to give the desired product as an orange gum which solidified upon standing at room temperature (4.7 g, 30%): 1H NMR (400 MHz, CDCl3) δ 9.04 (d, J=2.2 Hz, 1H), 8.76 (dd, J=4.8, 1.5 Hz, 1H), 8.15 (dt, J=8.1, 1.8 Hz, 1H), 7.42 (dd, J=8.1, 4.8 Hz, 1H), 6.84 (br s, 1H), 4.28 (d, J=5.2 Hz, 2H), 3.87 (s, 3H); ESIMS m/z 195 (M+1).

1. customThe aqueous washings of the crude reaction mixture
2. extractionextracted with dichloromethane (CH2Cl2)
3. custompurified by silica gel chromatography (ethyl acetate/hexanes gradient)
4. customto yield a yellow solid (1.6 g, 29%; total yield 3.4 g, 62%)
5. stirringstirred at 50° C. for 90 minutes (min)
6. filtrationThe reaction mixture was filtered through Celite®
7. concentrationthe filtrate was concentrated under reduced pressure
8. customThe crude product was purified by silica gel column chromatography (2% methanol/ethyl acetate)