Synthesis of some new annelated fused heterocyclic derivatives of biological importance

Abstract

The synthesis of the annelated fused heterocyclic derivatives is divided into two headings: Such as; annelated substrate and annelating reagent. The annelating substrates ortho-amino ester such as 2-amino-4,5-diphenylfuran-3-carboxylate (8), ethyl-5-amino-2- methylpyrozolo-4-carboxylate (2) and ethyl-2-amino-4,5-dimethylthiophene-3_carboxy_ late (14) were prepared from bezoin (7), ethyl(ethoxy methylene)malonitrile (1) and butanone (13) respectively by using Gewald method and annelating reagents such as 2- methylthio-2-methyl thiozoline (5) and 2-methylthio-imidazoline (11) were synthesized from ethanol amine (3) and ethylene diamine (9) respectively by using Jenson and Hofmann procedure. The annelating substrates were used to synthesize 2,3-diphenylfurano- 6, 7-dihydroimidazo(3 ,4-d]pyrimidin-4-one (12), 2-methyl-6,7 -dihydropyrazoio (3,4-d]thiozolo(l,2-d] pyrimi-din-4-one (6) and 2,3-dihydro-6,7-dimethyl-5H-thiazolo (3,2-a]thieno(2,3-d]pyrimidin-5-one (15) by one step reaction in dry acetic acid. in vitro antimicrobial activity of fused heterocyclic derivatives were evaluated. All these synthesized products of the fused heterocyclic derivatives have been employed as test chemicals for determining their antibacterial and antifungal activities against a number of human and plant pathogens. All the synthesized compounds dcmonstrated mild growth inhibition against antibiotic susceptible standard and clinically isolated strains of gram-positive and gram-negative bacteria as well as fungal pathogens.