Synthesis of some imidazolopyridopyazine from pentachloropyridine

In recent years, considerable attention has been given to the synthesis of benz- and bisimidazole derivatives due to their various pharmacological activities [1,2]. 2-chloromethyl- 1H-benzimidazole derivatives were prepared by condensing 2-chloromethyl-1Hbenzimidazole with different aliphatic, aromatic, and heteroaromatic amines. Several papers have been reported the preparation of these important compounds [3,4]. In this paper, firstly we have established a new method for the synthesis of these compounds in a short reaction time with high yields under ultrasonic irradiation then the reaction of N- ( 1Hbenzimidazole- 2- ylmethyl) aniline 3 with pentachloropyridine 4 in the presence of potassium carbonate in CH3CN as a solvent at reflux gave 1,2,4-trichloro-5-phenyl-5,6- dihydrobenzo[4,5]imidazo[1,2-a]pyrido[3,4-e]pyrazine 5 in good yields. The structure of products confirmed by IR, 1H-NMR and 13C- NMR.