Antimicrobial Activity of Halogen- and Chalcogen-Functionalized Thiazoloquinazolines

: The investigation is devoted to the assessment of the potential antimicrobial use of new chalcogen- functionalized thiazolo[2,3-b]quinazolin-5-ones, halides and trihalides of thiazolo[3,2- a]quinazolin-10-ium and tribromides thiazino[3,2-a]quinazolin-11-ium. The compounds under study were obtained by electrophilic intramolecular heterocyclization. A high bactericidal and fungicidal effect against some gram-positive and gram-negative bacteria and fungi has been revealed for the investigated compounds. The "structure-activity" relationship has been established; the influence of the chalcogen's nature and the type of substituents in the thiazoline and pyrimidine cycles on the biological activity of the investigated thiazolo- and thiazinoquinazolines is shown. Angular 4-methyl-5-oxo-1- ((trihalogenotellanyl)methylidene)-8-(trifluoromethyl)-1,2,4,5-tetrahydrothiazolo[3,2-a]quinazolin-10- ium halides have been found to show the highest bactericidal activity to the gram-negative culture of Escherichia coli.