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Cyanoacetic acid (51 g., 6 mole) was dissolved in 150 ml. of dioxane, the solution cooled to 5° C. and piperidine (53 g., 0.6 mole) dripped in while maintaining the temperature at 10°-15° C. Then, 37% aqueous formaldehyde (109.5 g., 1.35 mole) was slowly added at 0°-10° C. After two hours, the ice bath was removed and the mixture stirred overnight at 20°-25° C. It was then stripped at 15 mm. pressure and bath temperature of 48° C. The residue was chilled, mixed with 100 ml. of ether, saturated with sodium chloride and the ether layer separated. This extract was washed with two 25 ml. portions of cold 5% aqueous potassium carbonate and finally with 10 ml. of ice water. The ether solution was dried over anhydrous magnesium sulfate, filtered, stripped and fractionated using a Vigreux column. The fraction boiling at 86°-88° C./2 mm. was of practically analytical quality, 40.8 g., Rf 0.66 on silica gel using chloroform-methyl alcohol (90:10) development. This is, however, a known compound.

1. temperaturewhile maintaining the temperature at 10°-15° C
2. customthe ice bath was removed
3. custompressure and bath temperature of 48° C
4. temperatureThe residue was chilled
5. additionmixed with 100 ml
6. customof ether, saturated with sodium chloride and the ether layer separated
7. washThis extract was washed with two 25 ml
8. dry with materialThe ether solution was dried over anhydrous magnesium sulfate
9. filtrationfiltered