反应详情

10.0 g (0.028 mol) of the 4-(3,4-dimethylphenoxy)-1-carbobenzyloxy-3-piperidone described in Example 44 are dissolved in 60 ml of dry tetrahydrofurane and the solution is treated dropwise, at room temperature in a nitrogen atmosphere, with 112 ml of a 0.5 M solution of potassium tri-sec.-butyl-borohydride (K selectride) (0.056 mol) in tetrahydrofurane. After the addition has ended, the reaction mixture is stirred for a further 3 hours at room temperature and then concentrated to about 1/3 of the original volume under a water pump vacuum. The solution is cooled to 0° in an ice-water bath, treated dropwise with 130 ml of water and extracted by shaking with twice 150 ml of methylene chloride. The combined organic phases are washed with 0.1 N hydrochloric acid, then with 0.1 N sodium hydroxide solution and finally with water, dried over sodium sulphate and evaporated to dryness under a water pump vacuum. The oily crude product is dissolved in toluene and the solution is filtered through a layer of silica gel. cis-3-hydroxy-4-(3,4-dimethylphenoxy)-1-carbobenzyloxy-piperidine is obtained in the form of a pale yellow oil by elution with a toluene/ethyl acetate mixture (5:1).

1. additionAfter the addition
2. concentrationconcentrated to about 1/3 of the original volume under a water pump vacuum
3. temperatureThe solution is cooled to 0° in an ice-water bath
4. additiontreated dropwise with 130 ml of water
5. extractionextracted
6. stirringby shaking with twice 150 ml of methylene chloride
7. washThe combined organic phases are washed with 0.1 N hydrochloric acid
8. dry with materialwith 0.1 N sodium hydroxide solution and finally with water, dried over sodium sulphate
9. customevaporated to dryness under a water pump vacuum
10. dissolutionThe oily crude product is dissolved in toluene
11. filtrationthe solution is filtered through a layer of silica gel