Thiochromene candidates: design, synthesis, antimicrobial potential and in silico docking study

New sets of thiochromenes hybridized with five-membered rings as pyrazole and oxazole and/or six-membered ring as pyrimidine and thiopyrimidine were constructed. The novel constructed compounds were evaluated for their antimicrobial potential against B. subtilis and S. aureus as examples of gram-positive-bacteria, E. coli and P. aeruginosa as examples of gram-negative bacteria in addition to A. flavus and C. albicans as fungal strains. The results recorded promising antimicrobial potential with inhibition zone diameter range from 8 to 25 mm against the tested bacteria. Regarding antifungal activity, all the screened compounds revealed antifungal effect against A. flavus except thiochromene derivative 4 with zone of inhibition ranged from 9 to 16 mm. Moreover, all compounds recorded moderate to high antifungal potential towards C. albicans (ZI range = 8–19 mm) except thioxopyrazolothiochromene derivative 6 which did not exhibit any effect. To suggest mode of action of these candidates as antimicrobials, in silico docking study was carried out inside dihydropteroate synthase enzyme. Compound 8c recorded the best binding energy score (−5.47 kcal/mol) forming good fitting within DHPS active site.