The oximation of a variety of carbonyl compounds was efficiently carried out with DOWEX(R)50WX4/ NH 2 OH·HCl system. The reactions were performed in ethanol to give Z-aldoximation isomers of aldehydes and E-oximaton of acetophenone derivatives in a perfect selectively. The oximation of compounds with two carbonyl groups was carried out selectively on one carbonyl moiety. Also, the oximation of aldehydes over ketones has been accomplished successfully by this system.

In this study, oxalic acid has been successfully loaded on Fe3O4/PEG-400 under ultrasonic irradiation and Fe3O4/PEG/oxalic acid as a new nanomagnetic catalyst has been synthesized. The chemical structure of the catalyst has been investigated by FT-IR spectrum, XRD, EDX and SEM methods. The catalyst has been used for the synthesis of 3-acyl-5-hydroxy-3-pyrrolin-2-one derivatives from the corresponding aldehydes, anilines and dimethyl acetylenedicarboxylate (DMAD) by one-pot and three-component the MCR reaction in the excellent yields (90-95 %) of products within 24 hours at room temperature. The fourteen samples are available. The recovered catalyst could be satisfactorily used for the second and third run without regeneration. This method has green and eco-friendly profile. Also, this research introduces an improvement mechanism for the types of this reaction. The chemical structures of new compounds have been characterized by FT-IR, 1H-NMR, 13C-NMR, and Mass spectra.