Novel 2-thiazolylphthalazine derivatives were efficiently synthesized under ultrasound irradiation, resulting in high yields and short reaction times after optimization of the reaction conditions. All prepared compounds were fully characterized using spectroscopic methods. They were screened for their antimicrobial activity against Gram-positive and Gram-negative bacteria as well as for antifungal activity. The antimicrobial activity profile of the tested compounds showed some promising results. The potent activity of compounds 4d, 7b (117% zone inhibition) and 7c (105% zone inhibition) against Salmonella sp., exceeding that of the reference drug Gentamycin is particularly noteworthy. In general, the newly synthesized thiazolylphthalazine derivatives showed higher antimicrobial activity against the tested Gram-negative bacteria than against Gram-positive bacteria and fungi.
Keywords: antimicrobial activity; hydrazonoyl chlorides; thiazolylphthalazinediones; ultrasound irradiation.