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 and Crystal Structure of Trans-4-[(5-(2,4-Dichlorophenoxy)-3-methyl-1-phenyl-1H-pyrazol-4-yl)methyleneamino]-1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-one

The title compound trans-4-[（5-（2,4-dichlorophenoxy）-3-methyl- 1-phenyl-1H-pyrazol-4-yl）methyleneamino]- 1,5-dimethyl-2-phenyl-1,2-dihydropyrazol-3-one 3 （C28H23Cl2N5O2, Mr = 532.41） has been synthesized and its crystal structure was determined by single-crystal X-ray diffraction analysis. It crystallizes in triclinic, space group P1- with a = 8.9438（4）, b = 11.6065（5）, c = 14.2215（6）A, α = 112.566（1）, β = 92.324（2）, γ = 102.91（1）°, V= 1315.65（10） A^3, Z = 2, Dc = 1.344 g/cm^3,μ（MoKa） = 0.282 mm^-1, λ = 0.71073 A, F（000） = 552, the final R = 0.0587 and wR = 0.1578 for 5071 observed reflections （I 〉 2σ（I））. X-ray analysis reveals that the product is a thermodynamically stable trans isomer. Intra- and intermolecular C（ 12）-H（12）…O（1） and C（28）-H（28）...O（1）# 1 hydrogen bonds were observed in the title compound.

Two New Schiff Bases Based on 5-Chloro-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde: Syntheses, Crystal Structures and Properties

Two new Schiff bases based on 5-chloro-3-methyl-1-phenyl-1 H-pyrazole-4-carbaldehyde, namely, N-((5-chloro-3-methyl-1-phenyl-1 H-pyrazol-4-yl)methylene)-4-morpholinoaniline(Ⅲa) and N-((5-chloro-3-methyl-1-phenyl-1 H-pyrazol-4-yl)methylene)-3-fluoro-4-morpholinoaniline(Ⅲb), were synthesized and characterized by IR, LC-MS, 1 H NMR and 13 C NMR spectroscopy. Meanwhile, the three-dimensional configurations of the two title compounds were further characterized by single-crystal X-ray diffraction analyses. Both the compounds are thermodynamically stable trans-isomers. Moreover, the fluorescence properties and antioxidant activities against DPPH of the two target compounds have been investigated, and the results showed that the title compounds both have fluorescence performance and certain antioxidant activities against DPPH radical.

Coupling Reaction of 4-Chloro-7-H-Pyrrolo[2,3-d]Pyrimidine with 2,3,5-Tri-O-Acetyl-b-D-Ribofuranosyl Chloride

Coupling reaction of 4-chloro-7-H-pyrrolo[2,3-d]pyrimidine with 2,3,5-tri-O-acetyl -β-D-ribofuranosyl chloride under the basic condition was investigated. An abnormal coupling reaction, in which the heterocyclic base attacked at the carbon of 1,2-O-methylidene moiety instead of anomeric carbon of ribose was observed and the structure of products 5a, 5b were identified by NMR and X-Ray diffraction.

(Z)-N-(3-(2-Chloro-4-nitrophenyl)-4-methylthiazol-2(3H)-ylidene) Pivalamide: Synthesis and Crystal Structure

Synthesis of the title compound was carried out by base-catalyzed cyclization of 1-pivaloyl-3-(2-chloro-4-nitrophenyl) thiourea with α-bromoacetone produced in situ. The structure was confirmed by the spectroscopic and elemental analysis and single crystal X-ray diffraction data. It crystallizes in the triclinic space group P-1 with unit cell dime sions a = 8.7137(10), b = 10.2010(14), c = 10.6593(13), α = 62.671(9), β = 82.701(10), γ = 79.762(10), V = 827.21(8) ?3, Z = 2.

Green,mild and efficient bromination of aromatic compounds by HBr promoted by trans-3,5-dihydroperoxy-3,5-dimethyl-1,2-dioxolane in water as a solvent

A combination of HBr and trans-3,5-dihydroperoxy-3,5-dimethyl-1,2-dioxolane as anew and powerful oxidant was found effective for facile brotnination of different aromatic compounds at room temperature in water as a green solvent.Mild reaction conditions,high selectivity and yield,high reaction rate and non-toxicity are some of the major advantages of this synthetic protocol.

An approach to synthesis of(Z)-2-chloro-1,3-diarylpropen-1-ones by Vilsmeier reagent(bis-(trichloromethyl)carbonate/DMF)

A series of（Z）-2-chloro-1,3-diarylpropen-1-ones were unexpectedly synthesized in moderate yields by treatment of easily available 2,3-epoxy-1,3-diarylpropan-1-ones with Vilsmeier reagent,which was derived from bis（trichloromethyl） carbonate（BTC, triphosgene） and DMF.A possible mechanism was also proposed,where sequential ring-opening,halogenation and elimination reactions were involved.

A Novel One-Pot and Efficient Procedure for Synthesis of New Fused Uracil Derivatives for DNA Binding

Hydrazinolysis of 6-chloro-1-methyluracil followed by condensation of the product with different aromatic aldehyde gives the respective hydrazones which undergoes oxidative cyclization using thionyl chloride to obtain pyrazolo[3,4-d]pyrimidines in good yields. On the other hand, nitrosation of 6-aminouracils followed by the reaction with different arylidineanilines gives new xanthine derivatives. Finally, indenopyrrolopyrimidine and indenopteridine are obtained in good yields via the reaction of 6-aminouracils and 5,6-diaminouracil with ninhydrin respectively. The newly synthesized compounds show binding, chelation and fragmentation of the nucleic acid DNA.

Mild and Efficient Synthesis of 1-（6-Chloroquinoxalin-2-yl）-2- [4-（trifluoromethyl）-2,6-dinitrophenyl] Hydrazine Derivatives by Microwave Irradiation

Some 1-（6-chloroquinoxalin-2-yl）-2-[4-（trifluoromethyl）-2,6-dinitrophenyl] hydrazine derivatives have been synthesized via both conventional and microwave assisted organic synthesis（MAOS） methods. The MAOS method is more effective on synthesizing these compounds than the conventional method in regard to the higher chemical yields of products（76%-98%） and the shorter reaction time（1-15 min）.

Purification and characterization of a novel carbonyl reductase with high stereo-selectivity

A novel NADPH-dependent carbonyl reductase was separated from Candida parapsilosis CCTCC 203011.The enzyme gave a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE),which was purified through ammonium sulfate,Diethylamino Ethanol(DEAE)sepharose Fast flow(FF),phenyl-sepharose FF and blue sepharose FF chromato graphy from cell-free extract.The molecular mass of the enzyme was about 30 kDa.The optimum pH and temperature for reduction were 4.5℃ and 35℃,respectively.The Cu2+had strong restrictive effect on enzyme activity.In addition,the carbonyl reductase was an enzyme with high substrate specificity and stereo-selectivity,and showed high asymmetric reduction activity towards a-hydroxyacetophenone and ethyl 4-chloro acetoacetate.For the asymmetric reduction of a-hydroxyacetophenone and ethyl 4-chloro acetoacetate,(S)-1-phenyl-1,2-ethanediol and(R)-ethyl 4-chloro-3-hydroxybutanoate were produced by the purified enzyme,with the 100% and 94.3%e.e.value,respec-tively.Therefore,the enzyme could be one of the effective biocatalysts for asymmetric synthesis of chiral alcohols.The amino acid sequences of one peptide from the purified enzyme were analyzed by LC-MASS-MASS,and the car-bonyl reductase showed some identity to the hypothetical protein CaO19.10414 reported.