One Pot Synthesis of Oximes from Carbonyl Compounds Catalysed by Vanadium(V) Complex

Background: An eco-friendly catalyst was synthesized in good yield and characterized by various physicochemical techniques. The catalytic performance of the environmentally benign complex was investigated via slurry synthesis of oximes. The catalytic studies were successfully carried out using a simple protocol. The fascinating advantage of this protocol is cost effectiveness, simple work up, good yield, short reactions time, and milder reaction conditions. Methods: The complex was prepared by reaction of vanadium pentoxide with hydrazone ligand in 1:1 molar ratios, and to this reaction mixture, potassium carbonate (0.14 g, 1 mmol) was added and ground till fine yellow colour powder appeared. Oximations were carried out by reacting the substrates, 15 % H2O2, ammonia and vanadium(V) complex. The reaction was taken in a mortar and ground till a fine powder appeared. After completion of the reaction, the crude product was extracted using dichloromethane/ water in 1:2, v/v, evaporated and dried under vacuum. Results: We synthesized different varieties of oximes using our newly synthesized complex as a catalyst. The products were characterized by ¹H NMR and ¹³C NMR spectroscopy. The completion of the reaction was monitored by checking the complete disappearance of the aldehyde proton and the appearance of oxime protons. We also grew some single crystals of the products to provide further supporting evidences about the formation of products. Conclusion: Oximation of various carbonyl compounds was prepared quantitatively under the slurry condition, using {[K(H-2O)3][V(O)2L]}2 as a catalyst. The catalytic reactions can be carried out under mild conditions, with ease of scalability, and straightforward work-up procedure, which makes the present protocols greener and better alternative methods for the synthesis of oximes.