The synthesis, anticancer and antimicrobial properties of novel N-aryl-2-(5-aryltetrazol-2-yl)acetamides were discussed. Novel N-aryl-2H-tetrazoles were synthesized and modified in order to obtain the compounds with a satisfactory pharmacological profile. The structures of target substances were confirmed by using 1 H spectroscopy, mass spectrometry and elemental analysis. Anticancer activity screening was carried out within the framework of Developmental Therapeutic Program of the National Cancer Institute's (DTP, NCI, Bethesda, Maryland, USA).
The compounds with significant levels of anticancer activities have been found that can be used for further optimization. The antimicrobial activity of the synthesized substances was evaluated by the value of the MIC and minimum fungicidal and bactericidal concentration. The findings exhibited that the compounds possessed moderate antimicrobial potential

By the reaction of (4-furan-2-yl-thiazol-2-yl)- 3a and (4-thiophen-2-yl-thiazol-2-yl)- 3b acetonitriles with furfural 4 and 5-arylfurfyrals 5a-g 3-furan-2-yl-2-(4-furan/thiophen-2-ylthiazol-2-yl)acrylonitrile derivatives 6a-i were obtained. Anticancer activity screening was carried out within the framework of Developmental Therapeutic Program of the National Cancer Institute's (DTP, NCI, Bethesda, Maryland, USA). It was found out that (2E)-3-(2-furyl)-2-[4-(2-furyl)-1,3-thiazol-2-yl]acrylonitrile (6a) and 2-(4-thiophen-2-yl-thiazol-2-yl)-acrylonitriles 6h,i possessed low activity and 2-(4-furan-2-yl-thiazol-2-yl)acrylonitrile derivatives 6b-g showed moderate action. Compounds 6b-g were sensitive to cell lines of MDA-MB-468 and T-47D Breast Cancer. In this case cytotoxic effect was observed with a range of GP = -38.24 –1.28%.

A series of some new pyrazole-substituted 7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazines was synthesized in this study. The structures of target substances were confirmed by using 1H and 13С NMR spectroscopy, mass spectrometry and elemental analysis. The synthesized compounds have been evaluated for antimicrobial activity against five bacterial strains (Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Staphylococcus aureus) and two fungal strains (Candida albicans and Cryptococcus neoformans). The antimicrobial screening studies of synthesized substances established that 2 of 12 compounds show pronounced antibacterial activity against the strain Staphylococcus aureus.

A series of novel 1,3,4-thia(oxa)diazole substituted 2-(2,4-dioxothiazolidine-5-ylidene)-acetamides 3a-c, 4 and 5a-k have been synthesized following the acylation reaction of 2-amino-5-aryl-1,3,4-oxadiazoles, 5-amino-1,3,4-thiadiazole-2-thiol and it’s S-alkylated derivatives with 2-(2,4-dioxothiazolidine-5-ylidene)acetyl chloride in dioxane medium. The functionalization of compounds 3b, 3c, 5d and 5e was carried out on their N3 position under N-alkylation conditions with N-aryl-2-chloroacetamides in DMF/ethanol medium yielded the corresponding 2,4-dioxothiazolidine-3,5-diacetic acid diamides 6a-e and 7a-b. The structures of target compounds were confirmed by using 1H NMR spectroscopy and elemental analysis. The antioxidant activity evaluation in vitro of the synthesized compounds was performed by the method of scavenging effect on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals. As a result, the highly active compound 4, namely 2-(2,4-dioxothiazolidin-5-ylidene)-N-(5-mercapto-[1,3,4]thiadiazol-2-yl)acetamide was found to be the most efficient candidate among all compounds with a radical scavenging ability of 88.9%, which was comparable that for ascorbic acid (92.7%). The experimentally calculated IC50 value of 43.1 μM for compound 4 was lower than for ascorbic acid (50.5 μM).

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