Synthesis, oxygenation and catalytic performance of manganese complex with p-aminomethyl benzoic acid Schiff base

Abstract

The amino acid Schiff base complex (Sal-AMBA-Mn) was prepared with p-amino-methylbenzoic acid, salicylaldehyde and Mn(OAc)₂·4H₂O. Its structures was characterized with IR and UV spectra. Oxygenation mechanism of the complex in N, N-dimethylformamide solution was investigated. The results show that lower temperature is in favor of the oxygenation, and energy, enthalpy and entropy are −3.8 kJ/mol, −4.2 J/mol and −161.44 J/(mol·K), respectively. In the presence of the manganese complex, dehydroepiandrosterone acetate is effectively oxidized by molecular oxygen and the corresponding enone 7-ketodehydroepiandrosterone acetate is obtained. The yield is 62.1% when the oxidation is carried out under the reaction conditions of 60 °C, 2 MPa of O₂ pressure, C₅H₅N as a solvent and molar ratio of the substrate to the complex of 1:10.

Keywords

amino acid Schiff base / manganese complex / oxygenation / catalysis / dehydroepiandrosterone acetate / aerobic oxidation