Coumarin substituted pyrrolo-fused heterocyclic systems by 1,3-dipolar cycloadditon reactions

A variety of new pyrrolo-fused heterocyclic systems bearing a 3-carbonylchromen-2-one moiety on the pyrrole rings was obtained based on 1,3-dipolar cycloaddition reactions of corresponding cycloimmonium-ylides, generated in situ from the quaternary salts of several N-heterocycles with 3-(2-bromoacetyl)-2H-chromen-2-one, with electron-deficient alkynes. The synthetic strategies were both one-pot, three-component and classical multistep 1,3-dipolar cycloaddition reactions. The all newly synthesized compounds were structurally characterized by elemental analysis, IR and NMR spectroscopy.