反应详情

A solution of 1 mmol of 3-ethoxycarbonylmethyl-2-oxo-piperidine-3-carboxylic acid ethyl ester, 1 mmol of calcium chloride, and 5 ml of methanol is cooled to 0° C. and treated with one portion of 1 mmol of sodium borohydride, keeping the temperature at 0-5° C. with cooling for 2 hours. The mixture is allowed to warm to room temperature overnight. The solids are filtered and washed with methanol. The methanol filtrate is concentrated. The residue is triturated with diethyl ether and decanted. The residue is treated with water and the separated solid is filtered and washed with water. The aqueous filtrates are saturated with potassium carbonate and extracted with dichloromethane (3×) methylene chloride. The combined organic extracts and are dried over potassium carbonate, filtered, and concentrated. From the residue the crude title compound is identified on the basis of the Rf value. The title compound is used without further purification in the next stage.

1. customat 0-5° C.
2. temperaturewith cooling for 2 hours
3. filtrationThe solids are filtered
4. washwashed with methanol
5. concentrationThe methanol filtrate is concentrated
6. customThe residue is triturated with diethyl ether
7. customdecanted
8. additionThe residue is treated with water
9. filtrationthe separated solid is filtered
10. washwashed with water
11. extractionextracted with dichloromethane (3×) methylene chloride
12. dry with materialThe combined organic extracts and are dried over potassium carbonate
13. filtrationfiltered
14. concentrationconcentrated
15. customThe title compound is used without further purification in the next stage