Following the interaction of 2-chloro-N-(5-aryl-1,3,4-oxadiazole-2-yl) acetamides 1a-b with ammonium thiocyanate in dry acetone, the 5-unsubstituted 2-imino-4-thiazolidinones 4a-b have been synthesized. Compounds 4a-b were subsequently utilized in Knoevenagel condensation with aromatic aldehydes or isatin derivatives to synthesize the series of 5-arylidene/isatinylidene substituted 2-(1,3,4-oxadiazol-2-yl)imino-4-thiazolidinones 5a-h and 6a-d. The structures of target compounds were confirmed by using 1H NMR spectroscopy and elemental analysis. Evaluation of anti-cancer activity in
vitro for the synthesized compounds was performed following the National Cancer Institute protocol against leukemia, melanoma, lung, colon, CNS, ovarian, renal, prostate, and breast cancer cell lines. As a result, the most active compound 5a, namely 2-[5-(4-chlorophenyl)-[1,3,4]oxadiazol-2-ylimino]-5-(4-methoxybenzylidene)thiazolidin-4-one was found to be a highly efficient anti-tumor candidate with average logGI50 and logTGI values of -5.19 and -4.09, respectively

The 18 new thiazolo[4,5-b]pyridin-2-one derivatives have been synthesized using alkylation, cyanethylation, hydrolysis, and acylation reactions. The structures of the obtained compounds have been confirmed by 1H NMR spectroscopy, mass spectrometry, and elemental analysis. The study of the in vivo anti-inflammatory activity of the synthesized substances was assessed by using the functional model of carrageenan-induced rat paw edema. The present results of anti-inflammatory activity have shown that the synthesized compounds demonstrated considerable anti-inflammatory effects. Some of them approach or exceed the comparative drug Ibuprofen in terms of activity.