2-Butyl-5-chloro-3H-imidazole-4-carbaldehyde as a new synthon for the synthesis of fused ring heterocycles via intramolecular 1,3-dipolar cycloaddition reactions

(Chemical Equation Presented) The title compound 2-butyl-5-chloro-3H- imidazole-4-carbaldehyde was transformed into tricyclic heterocycles by substituting the chlorine atom by an unsaturated thiolate or alkoxide and then converting aldehyde function into 1,3-dipole. Chloramine-T was used as an efficient reagent for the generation of 1,3-dipoles, which resulted the formation of fused ring heterocycles via intramolecular 1,3-dipolar cycloaddition reaction. The method is very useful for the construction of many biologically active fused heterocycles.