反应详情

温度

25 °C

A solution consisting of 0.51 gm. (0.005 mole) diisopropylamine in 10 ml. tetrahydrofuran is chilled in an ice: methanol bath and 3 ml. of 1.68 N butyllithium in pentane is added. To this mixture is then added a solution consisting of 1.25 gm. (0.005 mole) 4-(p-chlorophenyl)-4-dimethylaminocyclohexanone (prepared in Example 2) in 20 ml. tetrahydrofuran. After 5 min. stirring, 1.42 gm. methyl iodide is added. This reaction is stirred for another 30 min. in the cold, and then it is allowed to warm up to 25° C. Stirring is continued for 21/2 hours, when 20 ml. saturated aqueous ammonium chloride is added. Benzene is also added. The organic solvents are removed by evaporation under reduced pressure. The residue thus obtained is transferred to a chromatographic column containing 200 ml. silica gel. The chromatogram is developed with 2 liters of a mixture of 3% methanol in methylene chloride followed by 2 liters of a mixture of 5% methanol in methylene chloride. The appropriate fractions as determined by TLC are combined. The solvent is removed by evaporation under reduced pressure giving the desired 4-(p-chlorophenyl)-2-methyl-4-dimethylaminocyclohexanone. The compound is recrystallized from diethyl ether to give an analytical sample having a melting point at 110° to 111° C. This is recognized to be the cis isomer by NMR spectroscopy.

1. additionTo this mixture is then added a solution
2. stirringThis reaction is stirred for another 30 min. in the cold, and then it
3. stirringStirring
4. custom2 hours, when 20 ml
5. customThe organic solvents are removed by evaporation under reduced pressure
6. customThe residue thus obtained
7. additioncontaining 200 ml
8. customThe solvent is removed by evaporation under reduced pressure