Elaboration of Guareschi Product for the Synthesis of Biologically Significant 3-Aminofuropyridine and Related Compounds

Abstract

Furopyridines are heterocyclic compounds having immense biological significance. Literature survey revealed that fuopyridines exhibit various biological activities such as anticancer, antibacterial, antiviral, antituberculotic, antioxidant and cytotoxic activities. The current research work was designed to synthesize furopyridine derivatives such as lkyl/aryl urea and alkyl/aryl thiourea substituted furopyridines Pyridine was synthesized by using economically beneficial protocol of Guareschi reaction. The reaction has been widely used in organic synthesis due to its mild conditions and high yields and the versatility of starting material. The synthesis of pyridone was achieved by reacting cyano acetamide and acetyl acetone in the presence of a sodium bicarbonate base, using water as the solvent, resulting in a high yield of the desired product. The pyridone was O-alkylated with phenacyl halide by SN2 reaction in the presence of potassium carbonate/acetonitrile, the yield of product was moderate because the solubility ofpyridone was not good enough This step was followed by intramolecular cyclization using sodium methoxide as base, leading to the formation of aminofuropyridine. Further, ethyl thiourea, phenyl urea and phenyl thiourea derivatives of furopyridine were synthesized from aminofuropyridine using different isocyanates. Characterization of the synthesized derivatives was done by using physical parameters including 'HNMR and 13CNMR.