Synthesis and Quantum Chemical Studies of polyfunctionally Substituted Pyridines Incorporating Pyrimidine Moiety for Corrosion Inhibition

Condensation of β-Oxo anilide 1 with malononitrile afforded 1,8-naphthyridine derivative 5. The reaction of 1 with each of cyanothioacetamide and ethyl cyanoacetate yields pyridine derivatives 7 and 10. Also, 1 reacted with each of arylidenecyanothioacetamide or a mixture of acetaledelyde/cyanothioacetamide to yield 5-acetylnicotinonitrile derivatives 15 and 17 respectively. Treatment of 15 with hydrazine hydrate afforded hydrazinonicotinonitrile derivative 18 . Furthermore, compound 15 was reacted with ethyl chloroactate to afford thieno[2,3– b ]pyridine derivative 20. Compound 17 reacts with elementary sulfur to yield the thienopyridine derivative 21 . Compound 21 reacted with arylidinemalononitrile yielding the isoquinolines 22a,b .Quantum chemical calculation optimization of DFT and frequency of synthesized compounds using Gaussian 09 and B3LYP methods. The basis set 6-31G (d,p) from which the descriptor was obtained explains the reactivity or stability of the synthesized compounds and their investigation as corrosion inhibitors. The results demonstrate the compound's potential as effective inhibitors of organic corrosion of some metals.