反应详情

Sodium cyanoborohydride (0.17 g, 27 mmol) and 5.2 g of 3A molecular sieves were slowly added at room temperature to a stirred solution of 1-phenylmethyl-3-methoxy-4-piperidone (5b, 1 g, 4.56 mmol) from Example 3 in 40 ml of methanol, 2.55 g (27 mmol) of aniline and 3.57 ml of 2.55N hydrochloric acid in methanol. The reaction mixture was stirred at room temperature for 3 days, after which time the molecular sieves were filtered off and the solution was made acidic with 10ml of 10% hydrochloric acid. The methanol was evaporated under vacuum and the residue was diluted with 20 ml of water, then extracted with ether (50 ml). The aqueous layer was then made alkaline with 10% sodium hydroxide (solution and extracted with 3×100 ml of ether. The combined organic layers were dried, then concentrated under vacuum and purified by column chromatography (silica gel; ethyl acetate/hexane; 1:1) to yield the intermediates cis-1-phenylmethyl-3-methoxy-4-phenylaminopiperidine (7b, 0.52 g, 38.23%) and trans-1-phenylmethyl-3-methoxy-4-phenylaminopiperidine (7b, 0.05 g, 3.7%).

1. filtrationafter which time the molecular sieves were filtered off
2. customThe methanol was evaporated under vacuum
3. additionthe residue was diluted with 20 ml of water
4. extractionextracted with ether (50 ml)
5. extractionextracted with 3×100 ml of ether
6. customThe combined organic layers were dried
7. concentrationconcentrated under vacuum
8. custompurified by column chromatography (silica gel; ethyl acetate/hexane; 1:1)