Abstract
Dry distillation of 4-aminobutyric acid and its ethyl ester, as acetyl, benzoyl, or nicotinyl derivative, with equal volume of soda lime or calcium oxide, affords 2-methyl-, 2-phenyl-, or 2-(3-pyridyl)-2-pyrroline in respective yield of 25, 85, or 95%. The yield increases if the dry distillation is carried out on the esters. Similar cyclization of the acetyl and benzoyl derivatives of glutamic acid by dry distillation only afforded 2-phenyl-2-pyrroline in 15% yield and 2-methyl-2-pyrroline was not obtained. From the diethyl nicotinylglutamate, a picrate was obtained in 20% yield of the starting material as golden yellow needles, m. p. 201-202°, the structure of which is still unknown. Catalytic reduction of the 2-pyrroline derivatives with palladium-carbon as a catalyst affords pyrrolidine derivatives in quantitative yield. For example, myosmine affords dl-nornicotine.
