A Novel Method for the Synthesis of Newfangled Asymmetric Schiff Bases from α‐amino Acids under Ultrasonic Conditions and in Aqueous Medium

Abstract

Chiral Schiff bases were obtained at high yields via a novel technique. Aryl aldehydes and chiral α‐amino acids were treated (1) in the presence of H3PO4 in ethanol at 80°C for 24 h, and (2) in the presence of K2CO3 under ultrasonic conditions in an aqueous ethanol medium within 5 min with yields reaching up to 96%. The results showed that the presented methodology under ultrasonic conditions was effective, practical, and eco‐friendly compared to that using an acidic medium. The corresponding asymmetric Schiff bases were synthesized for the first time, and were characterized by 1H and 13C nuclear magnetic resonance and infrared spectroscopy and high‐resolution mass spectrometry.

Preferential Enrichment of Enantiomer from Amino Acid Schiff Bases by Coordination Interaction and Crystallization

“…They typically occur in one of two possible enantiomeric forms, D forms and L forms [ 2 , 3 , 4 ], and they are also central sources of steric chiral carbon atoms. Salicylaldehyde-modified amino acids are among the most commonly used strategies for obtaining chiral ligands [ 5 , 6 , 7 , 8 , 9 , 10 , 11 ]. Their tridentate chelation coordination modes make it easier to interact with metal ions, which have antibacterial and antitumor activities after forming complexes.…”

Investigation of Methanol Behavior at the Designed Electrochemical Sensor based on Ni(II) Complex and Graphene Nanosheets

“…Recently, Schiff base complexes with different metals have been applied in the electrochemistry field . Such complexes have the property that the central atom (Ni) can be used as a catalyst in electrochemical reduction reactions because of its surface oxidation properties and catalytic behavior toward alcoholic functional group .…”