A novel approach has been adopted for the synthesis of Indolizine nucleus. Pyridinium-N-methylides (1a, b) were synthesized by reacting pyridine with different haloacetic acids. Further, the indolizine nucleus were synthesized through 1,3-cycloaddition of pyridinium-N-methylides with electron deficient alkynes or alkenes in presence of MnO2 to give indolizine carboxylates (2a, b). Later on, derivatives of indolizine (4a-d) were prepared by treating 2a and 2b with hydralazine and metformin. Synthesis of indolizine 2-carboxylic acid was achieved, by reacting 2- methyl pyridine with ethylbromopyruvate. The resulting acid was treated with hydralazine and metformin to form corresponding indolizine derivatives (5a, b). Synthesized compounds were characterized by IR and NMR spectroscopic techniques.
