反应详情

温度

20 °C

To a continually stirred, ice-cold solution of 2,3′-bipyridine-3-carboxylic acid (0.28 g, 1.40 mmole) in dry tetrahydrofuran (10 ml) and triethylamine (0.20 ml, 1.43 mmole) ethyl chloroformate (0.14 ml, 1.46 mmole) was added drop-by-drop over a 30 minute period. The precipitated product was then filtered and washed several times with tetrahyrofuran (3×2 ml). The THF phases were combined, cooled to +10° C., and while stirring under an argon atmosphere, sodium borohydride (0.185 g, 4.9 mmole) was added and then methanol (0.90 ml, 22.2 mmole) was added drop-by-drop over a 1 hour period during which time the temperature increased to 20° C. (Soai et al., 1987). The material was stirred for an additional 1 hour at room temperature. Then, 1N hydrochloric acid was carefully added, the solvent was evaporated under vacuum to 5 ml and washed with dichloromethane (3×5 ml). Sodium carbonate (0.85 g) was added to the aqueous phase, which was then extracted with dichloromethane. The combined fractions were dried with magnesium sulfate and evaporated under vacuum (2 Hg mm, 45° C.) giving a pure product (0.22 g, 84%). 1H-NMR, δ, ppm, 8.71 (1H, dd, J=2.1, 0.6 Hz, C2′-H), 8.55 (1H, dd, J=4.8, 1.5 Hz, C6-H), 8.52 (1H, dd, J=4.8, 1.8 Hz, C6′-H), 7.95 (1H, dd, J=7.8, 1.5 Hz, C4-H), 7.91 (1H, ddd, J=7.8, 2.1, 1.8 Hz, C4′-H), 7.35 (1H, ddd, J=7.8, 4.8, 0.6 Hz, C5′-H), 7.31 (1H, dd, J=7.8, 4.8 Hz, C5-H), 4.58 (2H, s, CH2—O).

1. filtrationThe precipitated product was then filtered
2. washwashed several times with tetrahyrofuran (3×2 ml)
3. temperaturecooled to +10° C.
4. stirringwhile stirring under an argon atmosphere
5. stirringThe material was stirred for an additional 1 hour at room temperature
6. customthe solvent was evaporated under vacuum to 5 ml
7. washwashed with dichloromethane (3×5 ml)
8. additionSodium carbonate (0.85 g) was added to the aqueous phase, which
9. extractionwas then extracted with dichloromethane
10. dry with materialThe combined fractions were dried with magnesium sulfate
11. customevaporated under vacuum (2 Hg mm, 45° C.)