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ABSTRACT. The present study describes the synthesis of 4,5-dihydro-6-(4-methoxy-3-methylphenyl)-3(2H)-pyridazinone derivatives. The synthesis of the first target compound, 4,5-dihydro-6-(4-methoxy-3-methylphenyl)-3(2H)-pyridazinone (1), was achieved by Friedel-Crafts acylation of o-cresyl methyl ether with succinic anhydride and subsequent cyclization of the intermediary g-keto acid with hydrazine hydrate. Condensation of compound 1 with aromatic aldehydes in the presence of sodium ethoxide affords the corresponding 4-substituted benzyl pyridazinones (3a-d). The dihydropyridazinone 1 underwent dehydrogenation upon treatment with bromine/acetic acid mixture to give (4). Pyridazine (5) has been synthesized upon the reaction of pyridazinone (1) with 1,3-diphenyl-2-propen-1-one under the Michael addition reaction. N-dialkylaminomethyl derivatives 6a-b have been obtained from the reaction of pyridazinone 1 with formaldehyde and secondary amine, whereas reaction of 1 with formaldehyde gives N-hydroxymethyl derivative (7). This study also includes the synthesis of the 3-chloropyridazine derivative 8 in excellent yield by heating pyridazinone 3b in phosphorus oxychloride. The behaviour of the chloro derivative toward sodium azide, benzyl amine and anthranilic acid was also studied. The proposed structures of the products were confirmed by elemental analysis, spectral data and chemical evidence.

A series of novel amino acid derivatives has been synthesized by the reaction of 4-[4-methoxy-3-methylphenyl]-4-oxobutenoic acid with primary and secondary amines. The treatment of amino acids with hydrazine afforded pyridazine. Phenylhydrazone was obtained from the reaction of the acid with phenyl hydrazine in ethanol. On the other hand, the acid underwent heterocyclization upon the treatment with 2-aminopyridine, o-phenylenediamine, aryldithiocarbamates and thiourea derivatives to give the corresponding pyridopyrimidine, quinoxalone, 2-thioxo-1,3-thiazole and 4-hydroxy-1,3-thiazole, respectively. The thiazolopyridazine derivatives were obtained from the reaction of 4-hydroxy-1,3-thiazole with hydrazine and phenylhydrazine, respectively. The behaviour of the 4-hydroxy-1,3-thiazole toward acetic anhydride and bromine was also studied. The proposed structures of the products were based on microanalytical and spectroscopic data. Some of the synthesized compounds also exhibited anti-microbial activities.

During water treatment, potentially hazardous chemical by-products may be formed. Alachlor (2-chloro-N-(2, 6-diethylphenyl)-N-(methoxymethyl) acetamide) is a widely used pre-emergence herbicide. The present study investigated the toxicity of alachlor and its disinfection by-products on freshly isolated rat hepatocytes. Hepatocytes were harvested by a collagenase perfusion technique and were exposed to different concentrations of alachlor and its by-products for up to 2 h. Cell viability, the leakage of aspartate transaminase (AST) and alanine transaminase (ALT) and glutathione (GSH) depletion were determined throughout the incubation period. The cell viability of the hepatocytes exposed to 100 microg ml(-1) alachlor was decreased by 20% compared with the control after 60 min of incubation. At the same concentration of alachlor the leakage of ALT and AST was increased by 56% and 45%, respectively. Cell viability of the hepatocytes was decreased upon exposure to 2-chloro-N-(3-chloro-2,6-diethylphenyl)-N-(methoxymethyl) acetamide (CCDMA) and 2-chloro-N-(3-chloro-2,6-diethylphenyl) acetamide (CCDA)--the by-products of alachlor and chlorine--after 60 min of exposure. At 100 microg ml(-1) CCDMA the AST leakage was increased significantly (73%) after 30 min of incubation. The reaction mixture of alachlor (100 microg ml(-1)) and chlorine dioxide (1 ppm) caused significant increases in cell loss and ALT and AST levels by 22%, 40% and 34%, respectively, as early as 15 min incubation. Alachlor (100 and 200 microg ml(-1)) caused significant decreases in GSH contents (62%) in isolated hepatocytes. The reaction mixture of alachlor and chlorine dioxide led to significant glutathione depletion (44%) after 60 min of incubation. The by-products of alachlor and chlorine--CCDMA and CCDA--depleted GSH almost completely (93%). This investigation suggested that the by-products formed from the reaction of alachlor and chlorine decreased GSH and increased the leakage of liver enzymes, especially AST.

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New and innovative textile fabrics coatings were facilely developed. The coating was developed based on synthesis of novel charring and antibacterial organic agent in conjunction with chitosan. N-[2,3-dibromo-4-(4-methoxy-3-methylphenyl)-4-oxobutanoyl]anthranilic acid was synthesized as organic antibacterial, reinforcement, and charring agent (OA) and then, dispersed in chitosan solution followed by coating on textile fabrics using immersion route forming new flame retardant coating layer. The developed organic molecule structure was elucidated using spectroscopic techniques. The mass loadings of developed organic agent dispersed in chitosan solution were varied between 20–60 wt.%. The coated textile fabrics have special surface morphology of fiber shape aligned on textile fibers surface. The thermal stability and charring residues of the coated textile fabrics were enhanced when compared to blank and organic agent free coated samples. Furthermore, the flammability properties were evaluated using LOI (limiting oxygen index) and UL94 tests. Therefore, the coated textile fabrics record significant enhancement in flame retardancy achieving first class flame retardant textile of zero mm/min rate of burning and 23.8% of LOI value compared to 118 mm/min. rate of burning and 18.2% for blank textile, respectively. The tensile strength of the coated textile fabrics was enhanced, achieving 51% improvement as compared to blank sample. Additionally, the developed coating layer significantly inhibited the bacterial growth, recording 18 mm of clear inhibition zone for coated sample when compared to zero for blank and chitosan coated ones.

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