反应详情

Under a nitrogen atmosphere, alpha-(4-picolylthio)-p-nitroacetophenone (0.45 g., 1.56 mmoles) and sodium cyanoborohydride (0.10 g., 1.56 mmoles) were dissolved in 15 ml. of dry methanol and a trace of bromocressol green pH indicator added (blue at 5.5, yellow at pH 3.8). The reaction was blue-green in color. Methanolic hydrogen chloride was added dropwise until the reaction turned yellow (pH approximately 4). Small additions of the methanolic hydrogen chloride were made, whenever the reaction darkened, for a period of 4 hours. The reaction was then left to stir for an additional 16 hours. The reaction mixture was concentrated to an oil which was taken up in 10 ml. of water and the product extracted into ethyl acetate (3 times 20 ml.). The combined ethyl acetate was back-washed with saturated sodium bicarbonate (2 times 15 ml.) and then with saturated sodium chloride, dried over anhydrous sodium sulfate and evaporated to yield 4-[2-hydroxy-2-(4-nitrophenyl)ethylthiomethyl]pyridine [0.347 g.; m.p. 135° -137° C.; ir (KBr): 3.25, 6.25, 6.6, 7.35, 9.35, 11.75, 13.75μ; pnmr/DMSO-d6 /TMS/τ: 7.2 (d, 2H), 6.5 (broad s, 1H). 6.2 (s, 2H), 5.1 (t, 1H), 2.6 (d, 2H), 2.3 (d, 2H), 1.7 (d, 2H), 1.4 (d, 2H)].

1. customwhenever the reaction darkened
2. waitThe reaction was then left
3. concentrationThe reaction mixture was concentrated to an oil which
4. extractionof water and the product extracted into ethyl acetate (3 times 20 ml.)
5. washThe combined ethyl acetate was back-washed with saturated sodium bicarbonate (2 times 15 ml.)
6. dry with materialwith saturated sodium chloride, dried over anhydrous sodium sulfate
7. customevaporated