Synthesis and Some New Indolizine and Pyrrolo[1,2-a]quinoline Derivatives via Nitrogen Ylides

The pyridinium bromides 2a,b reacted with dimethyl acetylenedicarboxylate (DMAD) to give the indolizine derivatives 6a,b.Bromide salts 2a,b reacted also with β-nitrostyrene, ethyl acrylate and with acrylamide to give the corresponding indolizine derivatives 8a,b and 10a-d.Reaction of the quinolinium salts 12a,b with DMAD, β-nitrostyrene and with ethyl acrylate as dipolarophiles furnished the corresponding pyrrolo[1,2-a]quinoline derivatives 16a,b, 18a,b and 20a,b, respectively.Bromide salts 2b and 22 underwent intramolecular cyclization via elimination of water and hydrogen bromide molecules when heated at reflux condition to give the angularly fused indolizine and pyrrolo[1,2-a]quinoline structures 21 and 23, respectively.