Linear and Angular Heteroannulated Pyridines Tethered 6-Hydroxy-4,7-Dimethoxybenzofuran: Synthesis and Antimicrobial Activity.

2-Chloropyridine-3-carbonitrile derivative was utilized as a key precursor to build a series of linear and angular annulated pyridines linked to a 6-hydroxy-4,7-dimethoxybenzofuran moiety. Reaction of substrate with various hydrazines afforded pyrazolo[3,4-]pyridines. Treatment of substrate with 1,3-,-binucleophiles including 3-amino-1,2,4-triazole, 5-amino-1-tetrazole, 3-amino-6-methyl-1,2,4-triazin-5(4)-one and 2-aminobenzimidazole produced the novel angular pyrido[3,2-][1,2,4]triazolo[4,3-]pyrimidine, pyrido[3,2-][1,2,4]tetrazolo[1,5-]pyrimidine, pyrido[3',2':5,6] pyrimido[2,1-][1,2,4]triazine and benzo[4,5]imidazo[1,2-]pyrido[3,2-]pyrimidine, respectively. Reaction of substrate with 1,3-,-binucleophiles including cyanoacetamides and 1-benzimidazol-2-ylacetonitrile furnished 1,8-naphthyridines and benzoimidazonaphthyridine. Moreover, reacting substrate with 5-aminopyrazoles gave pyrazolo[3,4-][1,8]naphthyridines. Finally, reaction of compound with 6-aminouracils as cyclic enamines yielded pyrimido[4,5-][1,8]naphthyridines. Some of the synthesized products showed noteworthy antimicrobial efficiency against all types of microbial strains. Structures of the produced compounds were established using analytical and spectroscopic tools.