Study of the Toxicity of 1-Bromo-3-Chloro-5,5-Dimethylhydantoin to Zebrafish

Objective 1-Bromo-3-chloro-5,5-dimethylhydantoin （BCDMH） is a solid oxidizing biocide for water disinfection.The objective of this study was to investigate the toxic effect of BCDMH on zebrafish.Methods The developmental toxicity of BCDMH on zebrafish embryos and the dose-effect relationship was determined.The effect of BCDMH exposure on histopathology and tissue antioxidant activity of adult zebrafish were observed over time.Results Exposure to 4 mg/L BCDMH post-fertilization was sufficient to induce a number of developmental malformations,such as edema,axial malformations,and reductions in heart rate and hatching rate.The no observable effects concentration of BCDMH on zebrafish embryo was 0.5 mg/L.After 96 h exposure,the 50% lethal concentration （95% confidence interval （CI）） of BCDMH on zebrafish embryo was 8.10 mg/L （6.15-11.16 mg/L）.The 50% inhibitory concentration （95% CI） of BCDMH on hatching rate was 7.37 mg/L （6.33-8.35 mg/L）.Histopathology showed two types of responses induced by BCDMH,defensive and compensatory.The extreme responses were marked hyperplasia of the gill epithelium with lamellar fusion and epidermal peeling.The histopathologic changes in the gills after 10 days exposure were accompanied by significantly higher catalase activity and lipid peroxidation.Conclusion These results have important implications for studies on the toxicity and use of BCDMH and its analogs.

Synthesis of 1-Bromo-3-methoxy-4-propoxy-5-iodobenzene——A Novel Efficient Process for the Synthesis of Brominated Aromatic Compound

The reaction of aromatic carboxylic acid with oxalyl chloride gives rise to the corres- ponding acid chloride which without purification is treated with the sodium salt of mercapto- pyridine oxide in the presence of 2,2-azo-bisisobutyronitrile (AIBN), radical initiator to give a brominated aromatic compound. After etherification and oxidation, 5-iodovaniline was converted to trisubstituted benzene carboxylic acid which give 1-bromo-3-methoxy-4-propoxy-5-iodo- benzene by this new brominating process with a yield of 74 %.

Synthesis and Crystal Structure of Methyl 3-(5-Bromo-1-ethyl-1H-indole-3-carbonyl)aminopropionate

Methyl 3-（5-bromo-l-ethyl-lH-indole-3-carbonyl）aminopropionate has been synthesized by the acylation of 5-bromo-3-trichloroacetylindole with β-alanine methyl ester, followed by alkylation with ethyl iodide, in 82.6% yield. Its crystal structure was gotten and determined by X-ray diffraction method. The crystal is of monoclinic, space group P2/c with a = 11.7927（8）, b = 14.9342（8）, c = 9.0060（5） A, β = 101.558（6）°, V = 1553.93（16） A3, Z = 4, Dc= 1.510 g/cm3, 2 = 0.71073 A,μ（MoKa） = 2.656 mm-1, Mr = 353.22 and F（000） = 720. The structure was refined to R = 0.0401 and wR = 0.0825 for 1704 observed reflections with I 〉 2σ（I）. In the crystal structure, intermolecular N（2）-H（2）...O（1） hydrogen bond and weak intermolecular bonds （C（1）-H（1）...O（1） and C（10）-H（10B）-O（2）） are formed, and π-π stacking also exists.

Synthesis and Crystal Structure of 4-Bromo-5-ethoxy-3-methyl-5- (naphthalen-1-yl)-1-tosyl-1H-pyrrol-2(5H)-one

The title compound 4-bromo-5-ethoxy-3-methyl-5-（naphthalen-l-yl）-l-tosyl-lH- pyrrol-2（5H）-one 1 （C24H22BrNO4S, Mr = 500.40） has been synthesized and its crystal structure was determined by single-crystal X-ray diffraction analysis. It crystallizes in monoclinic, space group P21/n with a = 8.8562（15）, b = 18.118（3）, c = 14.055（2）A, β = 99.855（3）^o, V= 2221.9（6）A3, Z = 4, Dc = 1.496 g/cm^3,μ= 1.975 mm^-1, 2 = 0.71073A, F（000） = 1024, R = 0.0607 and wR = 0.1371.

Preconcentration/Separation of Some Metal Ions Using Sodium Dodecyl Sulfate Coated Alumina Modified with Bis（5-bromo- 2-hydroxy-benzaldehyde）-2-methyl-1,5-pentane Diimine （BBHBPDI） Prior to Their Flame-AAS Determination

Preconcentration/separation of Co（II）, Fe（III）, Pb（II）, Cr（IIl）, Cu（II） and Cd（II） ions using bis（5-bromo- 2-hydroxy-benzaldehyde）-2-methy1-1,5-pentane diimine （BBHBPDI） on SDS coated alumina has been reported. The influences of the analytical parameters including pH, ligand and SDS amount, type and concentration of eluent and sample volume on metal ions recoveries were investigated. At optimum values of all variables the relative standard deviation are between 2.5-2.7 and preconcentration factor was 375, while recoveries for all understudy metal ions are higher than 95%, determination limits are between 1.5-2.7. The method has been successfully applied to determination of Co（II）, Fe（III）, Pb（II）, Cr（III）, Cu（II） and Cd（II） ions content in some real samples.

Competition of Aromatic Bromination and Nitration in Concentrated Sulfuric Acid

Composition of bromine and nitric acid in concentrated sulfuric acid is effective for bromination of strongly deactivated aromatic compounds and for nitration and bromination of moderately deactivated compounds in one stage. The question why brominating agent is more reactive than nitrating agent in relation to strongly deactivated aromatic compounds and is less reactive in relation to moderate deactivated ones is discussed.