反应详情

Referring to Scheme 3 below, N-cyclohexylpyrrolidine prepared in Example 1 (1 molar equivalent) was dissolved in methanol to 0.5M concentration in a three neck reaction flask equipped with a mechanical stirrer and reflux condenser. To the methanolic solution of cyclohexylpyrrolidine, 2 molar equivalents of methyl iodide were added, and the resulting mixture was left to stir overnight. The mixture was heated to reflux and left to stir at reflux for 4 hours. The reaction was cooled down and left to stir overnight. The reaction was complete. The reaction mixture was concentrated on a rotary evaporator. The resulting tan-colored solids were dissolved in isopropyl alcohol and then precipitated out from solution by adding diethyl ether. The precipitate was filtered out and dried on a rotary evaporator at reduced pressure and in hot water bath at 80° C. to give the desired N-methyl-N-cyclohexylpyrrolidinium iodide in 86% yield. N-Methyl-N-cyclohexylpyrrolidinium iodide was converted to the hydroxide by ion-exchanging the iodide ion with hydroxide ion. In a polyethylene plastic bottle, N-methyl-N-cyclohexylpyrrolidinium iodide salt was dissolved in deionized water (1 mmol salt/10 ml H2O). Then Bio-Rad AG 1-X8 resin (1.1 g resin/mmol salt) was added and the slurry-like mixture was gently stirred overnight. The exchange solution was then filtered and a small aliquot was titrated with 0.1N HCl to give 92% yield of the N-methyl-N-cyclohexylpyrrolidinium hydroxide.

1. customequipped with a mechanical stirrer
2. temperaturereflux condenser
3. waitthe resulting mixture was left
4. temperatureThe mixture was heated
5. temperatureto reflux
6. waitleft
7. stirringto stir
8. temperatureat reflux for 4 hours
9. temperatureThe reaction was cooled down
10. waitleft
11. stirringto stir overnight
12. concentrationThe reaction mixture was concentrated on a rotary evaporator
13. dissolutionThe resulting tan-colored solids were dissolved in isopropyl alcohol
14. customprecipitated out from solution
15. additionby adding diethyl ether
16. filtrationThe precipitate was filtered out
17. dry with materialdried on a rotary evaporator at reduced pressure and in hot water bath at 80° C.