反应详情

温度

104 °C

4-(Diphenylmethoxy)-1-(methyl)piperidine (prepared by neutralization of the commercial HCl salt; 4 g, 14.2 mmol, 1 equiv.) in anhydrous toluene (20 mL) was stirred at room temperature under nitrogen. Ethyl chloroformate (4.66 g, 43 mmol, 4.1 mL, 3 equiv.) was added dropwise over 5 minutes, whereupon significant effervescence was noted. The mixture was heated over the course of 1 h to reflux with an oil bath (bath temperature 104° C.). The mixture was then cooled to room temperature, whereupon more ethyl chloroformate (4 mL) was added. The mixture was heated at reflux (bath T=104° C.) for 7 h and again cooled to room temperature. The cooled mixture was concentrated and the residue purified by dry column chromatography (4×8.5 cm silica bed; 2:1 heptane:ethyl acetate) to yield 3.49 g (72%) of 4a as a slightly yellow oil. 1H NMR was consistent with the structure.

1. temperatureThe mixture was heated over the course of 1 h
2. additionwas added
3. temperatureThe mixture was heated
4. temperatureat reflux (bath T=104° C.) for 7 h
5. temperatureagain cooled to room temperature
6. concentrationThe cooled mixture was concentrated
7. customthe residue purified
8. dry with materialby dry column chromatography (4×8.5 cm silica bed; 2:1 heptane:ethyl acetate)