3-aryl-6-phenyl-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazines were obtained with good yields (81-95%) via the heterocyclization reaction of 1-phenyl-2-((5-aryl-1,3,4-oxadiazole-2-yl)thio)ethane-1-ones in acetic acid. The physicochemical characteristics of the synthesized compounds were established, the structures were confirmed by the data of IR, ¹H and ¹³C NMR spectra, as well as the results of X-ray diffraction analysis. The cytotoxic, antibacterial and antifungal properties of these compounds were evaluated. In vitro screening results showed that compounds 8, 9 and 12 significantly inhibit (54-65%) the growth of HeLa, HBL-100 and CCRF-CEM cancer cell lines. It was found that the cytotoxicity of the synthesized compounds increases in the series of oxadiazoltiones (1-4) - S-derivatives (5-8) - triazolothiadiazines (9-12). Compounds 5-16 do not exhibit antimicrobial properties.

Two heterocyclic Schiff bases namely (E)-2-(1-(2-phenylhydrazono)ethyl)pyridine (or 2-acetyl pyridine phenyl hydrazone) (2APPH) and (E)-2-(1-triazylidineethyl)pyridine (or 2-acetyl pyridine semicarbazone) (2APSC) were synthesized, characterized and their corrosion inhibition behaviour as well as mechanism of inhibition were investigated by different techniques. Structural characterization includes NMR, Mass, IR and UV-visible spectroscopy and elemental analysis. Corrosion inhibition behaviour of aforesaid compounds on mild steel in 1M hydrochloric acid was examined by electrochemical methods including potentiodynamic polarization analysis and electrochemical impedance spectroscopic techniques. The mechanism of corrosion inhibition was explored and supplemented by adsorption and surface morphological studies. Quantum mechanical investigations on corrosion behaviour of compounds were also conducted and satisfying correlation was noticed between the results of corrosion measurement methods and quantum mechanical evaluations.

Obtained by the interaction of 2-amino-3,3-dichloroacrylonitrile and chlorosulphonyl isocyanate (Z)-(5-(dichloromethylene)-2-oxoimidazolidin-4-ylidene)sulfamoyl chloride reacts easily with excess of the aliphatic amine to form new (Z)-N-(5-(dichloromethylene)-2-oxoimidazolidin-4-ylidene)-N'-substituted sulfonamides. According to the National Cancer Institute (USA) examinations, two of the six synthesized sulfonamides showed a high anticancer activity.