Studies on Polyfunctionally Substituted Azoles and Azines and Utility of These• Compounds as Pesticides Agents

Abstract

1.1 Utility of 1H-benzimidazole-2-acetonitrile for syntheses of novel polyfunctionally substituted heterocyclic compounds

1.1.1 Novel syntheses ofPyrido[1,2-a)benzimidazole Derivatives

It has been found that pyrido[1,2-a]benzimidazoles 3a,b, 9a,b,

23, 28, 29 were obtained via condensation reaction of 1H­ benzimidazole-2-acetonitrile 2 with -diketone, -ketoester, nitriloester, and -ketonitrile compounds. In the same manner, compound 2 was condensed with acetylacetone or benzoyl ace­ tone in glacial acetic acid and acetic anhydride to afford com­ pound 3a,b. Compound 3a undergoes coupling reaction with aryl diazonium chloride to afford 2-arylazopyrido[ 1,2-a]benzimidazole 6-8. Also, compounds 6-8 was obtained through reaction of compound 2 with arylazo of acetylacetone 5a-c in the previous reaction condition. On the other hand, ethyl acetoacetate, ethyl benzoylacetate and ethyl cyanoacetate were condensed with com­ pound 2 to afford 9a,b and 23 respectively. Compounds 9a,b or 23 were reacted with aryldiazonium chloride to give 2-arylazo­