Utility of 2, 4-Dihydroxybenzylidene Thiosemicarbazones in the Synthesis of Some Bioactive and Anti-Corrosive Heterocyclic Compounds

The important organic compound 3-((2,4-dihydroxybenzylidene) amino)-2-thioxoimidazolidin-4-one (3) has been prepared by the reaction of 2,4- dihydroxybenzaldhyde with thiosemicarbazide to give 2,4 dihydroxybenzylidene thiosemicarbazone (1), followed by cyclization of compound 1with ethyl chloroacetate in the presence of fused sodium acetate. The synthesized compound 3 was considered as the started material for synthesis some novel  thiohydantoin derivatives (4-13).Also2,4-dihydroxybenzylidene thiosemicarbazone(1) was used for the preparation of 2 and5.All the synthesized compounds have been characterized on the bases of IR, ¹H-NMR, ¹³C-NMR, mass spectrometer and elemental analyses. Some of 2-thiohydantoin derivatives (5,6,11) were tested for in-vitro antibacterial activity against Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis), Gram-negative bacteria (Salmonella typhimurium, Escherichia coli) and fungi (Candida albicans and Aspergillusfumigatus). This paper also interested with flame retardants and anticorrosive additives based on some previously prepared thiohydantoin derivatives 4-((2-(5-(4-methoxyphenyl) thiazol-2- yl) hydrazono)methyl) benzene-1, 3-diol (5),5-(2-chlorobenzylidene-3-(2, 4-dihydroxybenzylidene) amino)-2-thioxoimidazolidin-4-one (6),and 4 -(2-chlorophenyl)-1- (2,4- dihydroxybenzylidene )-6- oxo-2-thioxo-2,3,5,6- tetrahydro-1H-imidazo [4,5c]pyridine -7-carbonitrile (11), which were physically added to epoxy organic coating. The flame retardants technique was observed via a limited oxygen index (LOI) method, and anti-corrosive was evaluated with salt spray (or salt fog) test. The coating evaluation showed that, the incorporation of thiohydantoin derivatives into varnish improved the flame residency, corrosion resistance, and some physical properties of mild steel perversely coated with modified epoxy varnish