Síntese limpa promovida por ultrassom de 5-alquilideno-2pirrolidinonas derivadas do ácido levulínico

Abstract

This work describes the 5-alkylidene-2-pyrrolidinone synthesis by the reaction of methyl 7,7,7-trifluoro-4-methoxy-6-oxo-4-heptenoate and alkyl- and arylamines. The reaction was carried out using ethanol as solvent under ultrasonic conditions. When alkylamines were allowed to react, the 5-alkylidene-2-pyrrolidinones were obtained in good yields after 30-90 minutes of sonication. The reaction of aniline resulted in an excellent yield after 105 minutes. Reactions of substituted anilines yielded the products in a range of bad to excellent yields. Alkyl amines that contain bulky groups did not show ciclization (amines 2a and 2b) or gave mixtures that contain the cyclic product (5-alkylidene-2-pyrrolidinone) and the acyclic intermediate (β-enaminoketone) in the cases of 2c and 2d. All products were identified by 1H and 13C NMR, mass spectrometry and infrared spectroscopy.