反应详情

Ethyl 3-(2,6-dimethylpiperidino)propionate hydrochloride may be obtained by working according to the method described in Example 6 for the preparation of ethyl 3- diisopropylaminopropionate, but starting with ethyl 3bromopropionate (18.1 g), 2,6-dimethylpiperidine (27 cc) and ethanol (30 cc). The reaction mixture is concentrated to dryness under reduced pressure (2.7 kPa) and the residue obtained is taken up with water (50 cc) and 4N aqueous hydrochloric acid solution (30 cc). The aqueous phase is washed with ethyl ether (2×80 cc) and neutralized with 4N aqueous sodium hydroxide solution (40 cc). The insoluble oil is extracted with ethyl ether (3×120 cc); the organic extracts are then washed with water (2×80 cc) and concentrated to dryness under reduced pressure (2.7 kPa) at 40° C. The residue is dissolved in ethyl ether (100 cc). A 4.5N solution (13.4 cc) of gaseous hydrochloric acid in ethyl ether is added to the solution obtained. A product precipitates. It is separated by filtration, washed and dried in the air. Ethyl 3-(2,6-dimetylpiperidino)-propionate hydrochloride (14.4 g), m.p. 146° C., is thereby obtained.

1. concentrationThe reaction mixture is concentrated to dryness under reduced pressure (2.7 kPa)
2. customthe residue obtained
3. washThe aqueous phase is washed with ethyl ether (2×80 cc)
4. extractionThe insoluble oil is extracted with ethyl ether (3×120 cc)
5. washthe organic extracts are then washed with water (2×80 cc)
6. concentrationconcentrated to dryness under reduced pressure (2.7 kPa) at 40° C
7. dissolutionThe residue is dissolved in ethyl ether (100 cc)
8. additionA 4.5N solution (13.4 cc) of gaseous hydrochloric acid in ethyl ether is added to the solution
9. customobtained
10. customA product precipitates
11. customIt is separated by filtration
12. washwashed
13. customdried in the air