Cyclization of 3-Alkylamino-4-hydroxybutanamides in Alkaline Medium.

R = C6H5CH2 (a), C4H9 (b). Amides are known to undergo hydrolysis in the presence of both acid and base catalysts; as a rule, the hydrolysis is irreversible [3]. Our attempts to isolate substituted pyrrolidinone were unsuccessful. Presumably, it is not formed under the given conditions due to the presence of excess alkali. The IR spectrum of hydrochloride IVa contained a band at 1775 cm which is typical of carbonyl group in saturated lactones. The corresponding band in the IR spectrum of I was observed at 1640 cm. 4-Benzylaminofuran-2-one hydrochloride (IVa). A solution of 2.5 mmol of potassium hydroxide in ethanol was added with stirring to a heated solution of 1 mmol of N-benzyl-3-benzylamino-4-hydroxybutanamide in ethanol. The substrate consumption was monitored by TLC. After cooling, the mixture was acidified with hydrochloric acid to pH 335. The organic phase was diluted with ethyl acetate3diethyl ether (1 : 1), the precipitate was filtered off, and the filtrate was dried and evaporated under reduced pressure. The oily residue crystallized on addition of ethyl acetate. The precipitate was filtered off. Yield 73%. Colorless crystals, mp 1803181oC. IR spectrum, n, cm: 1140, 1355, 1430 (CAOAC), 1575 (dNH2 ), 1775 (CIO), 2405 (NH2 ). Found, %: C 58.06; H 6.24; Cl 15.71; N 6.10. C11H14ClNO2. Calculated, %: C 58.02; H 6.15; Cl 15.60; N 6.15.