Poly(ethylene glycol)-supported Liquid-phase Parallel Synthesis of Di(aryloxyacetyl)thiosemicarbazides

An efficient poly(ethylene glycol) (PEG)-supported liquid-phase parallel approach to di(aryloxyacetyl)thiosemicarbazides is described. PEG-bound phenol reacted with chloroacetic acid to afford PEG-bound phenyloxyacetic acid, which was readily converted into corresponding phenyloxyacetyl chloride. Subsequent nucleophilic substitution with ammonium thiocyanate followed by addition of aryloxyacetic acid hydrazides gave PEG-bound di(aryloxyacetyl)thiosemi-carbazides, which were easily cleaved to give the resulting library of 1-aryloxyacetyl-4-(4'-methoxylcarbonylphenyloxyacetyl)thiosemicarbazides in good to high yield and high purity.

One-pot Synthesis of 1-Aryloxyacety l-4-(4'-nitrophenyloxyacetyl)-thiosemicarbazides under Phase Transfer Catalysis and Microwave Irradiation

The 1-aryloxyacetyl-4-(4-nitrophenyloxyacetyl)-thiosemicarbazides (3a-h) are synthe- sized via reaction of 4-nitrophenyloxyacetyl chloride with ammonium thiocyanate and aryloxyacetic hydrazides (2a-h) under phase transfer catalysis and microwave irradiation in excellent yield.

New tricks for an old dog: Visible light-driven hydrogen production from water catalyzed by fac-and mer-geometrical isomers of tris(thiosemicarbazide) cobalt(Ⅲ)

Increasing interest has been paid to the development of earth‐abundant metal complexes as promising surrogates of platinum for the electrocatalytically and photocatalytically driven hydrogen evolution reaction.In this work,we report on molecular H2‐evolving catalysts based on two octahedral complexes of cobalt thiosemicarbazide,fac‐[Co(Htsc)3]Cl3·3H2O(C1,Htsc=thiosemicarbazide)and mer‐[Co(Htsc)3]Cl3·4H2O(C2),which have facial(fac)and meridional(mer)geometry,respectively.Electrochemical studies confirmed that both C1and C2are active electrocatalysts in MeOH solution using acetic acid as the proton source,with the same overpotential of^640mV and TOF of^210s–1.The complex C1also exhibits electrocatalytic activity for hydrogen evolution reaction in aqueous media free of organic solvent with a moderate overpotential(560mV).Visible light‐driven hydrogen evolution experiments were carried out in combination with fluorescein as photosensitizer and triethylamine as sacrificial reductant in homogeneous environments.Our studies showed that both C1and C2can be used as efficient proton‐reduction catalysts in purely aqueous solution and have the same photocatalytic activities.A TOF of125h–1with a TON of900for photocatalytic H2generation using C1and C2in water were achieved for the noble‐metal‐free homogeneous system.It should be noted that this is the first reported study investigating the effect on the catalytic hydrogen production performance of using fac‐and mer‐isomers of molecular catalysts.

Synthesis and Crystal Structure of Salicylyl-4-phenyl Thiosemicarbazide Lead with a Two-dimensional Network

A two-dimensional lead complex, [Pb（C14N3O2H12S）（NO3）]n·nH2O, was prepared by the reaction of salicylyl-4-phenyl thiosemicarbazide and lead nitrate. The compound （C14H13N4O6PbS, Mr = 572.53） crystallizes in the monoclinic space group P21/c with a = 11.2984（2）, b = 15.6628（7）, c = 11.1118（2）A,β= 113.564（2）°, V = 1802.43（10）A3, Dc= 2.110 g/cm3, Z = 4,μt（MoKα） = 9.515 mm-1, F（000） = 1084, the final R = 0.0394 and wR = 0.0701 for 2552 observed reflections with I 〉 2σ（I）. The Pb（Ⅱ） ion displays a distorted octahedron in which the hypothesized stereochemically active lone pair occupies the apex. The compound exhibits a two-dimensional network structure formed by the zigzag one-dimensional chains joined by two μ-O of two nitrate groups in overlapping. A large ring exists in the two-dimensional layers. The TGA of the title compound has been studied.

Synthesis,Crystal Structure and Fluorescent Properties of 1-(4-(Dimethylamino)benzylidene)-4-(naphthalen-1-yl) Thiosemicarbazide

The title compound, 1-4-（dimethylamino）benzylidene）-4-（naphthalene-1-yl） thiosemicarbazide （DMABNTS, C20H20N4S, Mr = 348.47）, was synthesized and characterized by elemental analysis, 1R, ^1H NMR and MS. The crystal structure of DMABNTS with 1,4-dioxane （Diox, C4H8O2） solvent molecules （DMABNTS·2Diox, C28H36N4O4S, Mr = 524.67） was determined by single-crystal X-ray diffraction. The crystal belongs to monoclinic system, space group P21/c with a = 14.418（4）, b = 7.1702（19）, c = 28.350（7）°A,β= 101.154（6）°, V= 2875.4（13） °A^3, Z= 4, Dc= 1.212 g/cm^3, F（000） = 1120 and μ= 0.151 mm^-1. A total of 6458 reflections were collected, of which 4671 were unique. The structure was solved by direct methods and refined to the final R = 0.0732 and wR = 0.2127 for 3921 observed reflections （I〉 2σ（I））. There exist intermolecular hydrogen bonds （N（2）-H（2B）…S（1A）and N（1）-H（1A）…O（4B）） in the structure. The study of fluorescent properties ＇shows that DMABNTS emits bright solid-state fluorescence in the visible region and exhibits blue photoluminescence.

Microwave-prompted Rapid and Efficient Synthesis of Diacyl Thiosemicarbazides and Semicarbazides in Solvent and Catalyst Free Condition

Eighteen 1-aroyl-4-（2-iodobenzoyl）thiosemicarbazides and corresponding semicarbazides were synthesized in excellent yield under microwave irradiation in solvent and catalyst free condition.

Synthesis and <i>in vitro</i>antibacterial evaluation of some thiosemicarbazides and thiosemicarbazones

In the present study various thiosemicarbazides and thiosemicarbazones were synthesized and screened for their antimicrobial activity. Among the ligands tested, compounds 1, 3, 4 and 5 demonstrated inhibitory effects at 0.4 - 0.5 μM concentrations against E. coli while 1-(4-fluorobenzoyl)-N4-ethyl-thiosemicar-bazide (3) demonstrated the maximum inhibitory effective compound against E. coli, also possessing high water solubility. Instead, compound 3 demonstrated weak antibiotic effects against S. aurous while compounds 4 - 6 demonstrated significant antibacterial effects at 0.4 - 0.42 μM against the latter organism. Chloramphenicol was used as the positive control.

Ethyl thiosemicarbazide intercalated organophilic calcined hydrotalcite as a potential sorbent for the removal of uranium(VI) and thorium(IV) ions from aqueous solutions

This work was conducted to determine the practicability of using a new adsorbent 4-ethyl thiosemicarbazide intercalated, organophilic calcined hydrotalcite （ETSC-OHTC） for the removal of uranium （U（Ⅵ））, and thorium （Th（Ⅳ）） from water and wastewater. The FTIR analysis helped in realizing the involvement of nitrogen and sulphur atoms of ETSC in binding the metal ions through complex formation. Parameters like adsorbent dosage, solution pH, initial metal ions concentration, contact time and ionic strength, that influence adsorption phenomenon, were studied. The optimum pH for maximum adsorption of U（VI） and Th（IV） was found to be in the range 4.0-6.0. The contact time required for reaching equilibrium was 4 hr. The pseudo second-order kinetic model was the best fit to represent the kinetic data. Analysis of the equilibrium adsorption data using Langmuir, Freundlich and Sips models showed that the Freundlich model was well suited to describe the metal ions adsorption. The KF values were 25.43 and 29.11 mg/g for U（Ⅵ） and Th（Ⅳ）, respectively, at 30℃. The adsorbent can be regenerated effectively from U（Ⅵ） and Th（Ⅳ） loaded ones using 0.01 mol/L HC1. The new adsorbent was quite stable for many cycles, without much reduction in its adsorption capacity towards the metals.

Syntheses and Antiproliferative Activities of Novel Diarylthiosemicarbazide Derivatives

A series of novel N-methylpicolinamide-moiety containing diarylthiosemicarbazide derivatives was prepared and evaluated for their in vitro antiproliferative activity against three cancer cell lines（human alveolar epithelial cell A549, human lung cancer cell H460 and human colorectal cancer cell HT-29） by 3-（4,5-dimethyl）thiazolyldiphenyltetrazoliumromide（MTT） assay. Six compounds（Tb--7g） with halogen substituents exhibited preferable cytotoxicity against one or more cell lines in a low micromolar range. Especially, the most promising compound 7g exhibited remarkable antiproliferative activity with the IC50 values of 2.2, 1.8 and 5.2 μmol/L against A549, H460 and HT-29 cell lines respectively, which is comparable to sorafenib.

Synthesis and Crystal Structure of a Mn(II) Complex with Thiosemicarbazone Derivative of Pyridine-3-carbaldehyde Showing Unusual Coordination Mode of Tridentate Thiosemicarbazone

The title complex Mn（HL）4（NCS）2（CH3CH2OH）2 has been achieved via selfassembly by incorporating manganese（Ⅱ） into pyridine-3-carbaldehyde thiosemicarbazonate ligand, and characterized by elemental analysis and single-crystal X-ray diffraction study. The crystal crystallizes in triclinic, space group PI^-, with a = 8.896（2）, b = 9.530（2）, c = 14.520（4）°A, α = 87.035（4）, β= 88.112（4）, γ= 69.434（4）°, V= 1150.9（5）°A^3, Z = 1, Mr = 984.17, Dc = 1.420 g/cm^3,μ（MoKα） = 0.612 mm^-1, F（000） = 511, the final R = 0.0574 and wR = 0.1547 for 2855 observed reflections with I〉2σ（I）. The complex contains one six-coordinated manganese ion connected by two thiosemicarbazide ligands, in which the thiosemicarbazone ligand acts as a monodentate ligand and coordinates to the center metal atoms via the pyridyl nitrogen atoms, two ethanol molecules and two isothiocyanic anions to give rise to a mononuclear structure. The coordination of a potentially tridentate thiosemicarbazone in manganese（Ⅱ） complex without using its sulfur and imine nitrogen sites is unusual. Hydrogen bonds existing in the complex link the different components to stabilize the crystal structure.

Some Novel Schiff Bases from Pyruvic Acid with Amines Containing N &S Donor Atoms: Synthesis, Spectral Studies and X-Ray Crystal Structures

Four Schiff bases, from pyruvic acid (1) with amines containing N and S donor atoms, thiocarbohydrazide (2, 61%), 2-methyl-3-thiosemicarbazide (3, 26%), S-benzyldithiocarbazate (4, 51%) and S-n-octyldithiocarbazate (5, 63%) have been successfully synthesized. The conventional method was used and a series of novel linear and cyclic Schiff bases were obtained with or without catalyst. All the Schiff bases were fully characterized by CHN elemental analysis, FT-IR, 1H & 13C NMR, EI-MS and two of the Schiff bases were further characterized by X-ray crystallographic structure analysis. Compound 2 crystallizes in the triclinic space group P-1 and unit cell dimensions are: a = 4.1777(8), b = 5.9538(11), c = 13.458(3) &ARING;, α = 92.759(6), β = 90.813(6), γ = 100.040(6)°, R1 = 0.0439. Compound 3 crystallizes in the orthorhombic space group P n a 2(1) and unit cell dimensions are: a = 5.5992(2), b = 11.3962(5), c = 10.6473(5), α = 92.759(6), β = 90.813(6), γ = 100.040(6)°, R1 = 0.0285. Compounds 2 and 3 were obtained as cyclic Schiff bases which are triazine derivatives.

The Reactions of 1-Acetothiosemicarbazidc with P(NR_2)_3 PC1_3 and PCI_5

A Series of new heterocyciophosphorus compounds were synthesizec oy cyclocondensa-tion of 1-acetothiosemicarbazide with P(NR2)3. The further reaction of these compounds with P(NR2)3 gave different compounds depending upon different reaction conditions. The 1-acetothiosemicarbazide can also condense with PCl3 and PCl5 similarly, The reaction mechanism, the spectral properties and chemical properties of these products were also studied and discussed.

Antibacterial Activities of New Schiff Bases and Intermediate Silyl Compounds Synthesized from 5-Substituted-1,10-phenanthroline- 2,9-dialdehyde

Schiff bases are known to possess anticancer, antibacterial, antifungal, antitubercular, anti-inflammatory, antimicrobial and antimalarial properties. In this paper antibacterial studies against variety of plants and human pathogenic bacteria with eight newly synthesized Schiff bases and several intermediate silyl compounds have been reported. The antibacterial activities of the synthesized compounds were primarily determined by paper disc diffusion method. The minimum inhibitory concentration (MIC) of each compound was also determined by tube dilution process. Seven different human pathogenic bacteria and eighteen different plant pathogenic bacteria were used for the antibacterial activity studies. While all synthesized compounds have shown significant antibacterial activity, one intermediate silyl compound has shown remarkably high antibacterial property. 5-substituted derivatives have shown relatively higher activity than non-substituted compounds. Polar substituent which increases hydrophilicity may have a positive impact on the antibacterial property.

Synthesis of 5-Substituted 2, 9-Dimethyl-1,10-Phenanthroline Dialdehydes and Their Schiff Bases with Sulfur-Containing Amines

Eight new Schiff bases of 5-nitro and 5-bromo-substituted 1,10-phenanthroline-2,9-dicarboxaldehydes with sulfur-containing amines, thiosemicarbazide, S-alkyl/aryl dithiocarbazates and 2-mercaptoaniline have been synthesized and characterized by a variety of spectroscopic methods. The condensation reactions of the dialdehydes with the amines were carried out both in the presence and absence of conc. sulfuric acid. A significant increase in yield of the Schiff bases was observed when the reactions were carried out in the presence of sulfuric acid.

An Expedient Method for the Synthesis of Thiosemicarbazones under Microwave Irradiation in Solvent-free Medium

A simple, efficient and eco-friendly method for the synthesis of thiosemicarbazones from thiosemicarbazides and aldehyde under microwave irradiation has been reported, and no solvent and catalyst were used. And the technique of microwave irradiation coupled with solvent-free condition proved to be a quite valuable method in the organic synthesis.

Preparation and application of novel chitosan-cellulose composite materials to adsorb Pb(Ⅱ)and Cr(Ⅵ)ions from water

This paper reported the preparation and application of novel chitosan-cellulose composite absorbents for the adsorption of Pb(II)and Cr(VI)ions in water.First,oxycellulose or dialdehyde cellulose(DAC)was prepared by sodium periodate oxidation of microcrystalline cellulose(MCC).Second,based on the mechanism of the Mannich reaction,a chitosan/cellulose-based adsorbent(TSFCD)was produced through a cross-linking reaction of thiosemicarbazide(TS)with DAC and chitosan(CS),which was designed specifically for the adsorption of Cr^(6+)ions from water.Similarly,another chitosan/cellulose-based adsorbent(DBFCM)was also prepared with 2,5-dithiobiurea(DB)as the cross-linking agent for the adsorption of Pb^(2+)ions in water.The adsorption performance of TSFCD and DBFCM for Cr^(6+)and Pb^(2+)ions,respectively,was investigated under various process conditions.Variables included adsorption temperature,time,initial metal ion concentration,pH,and adsorbent dosage.The adsorption kinetics of TSFCD and DBFCM were studied,and isothermal models were developed.Results showed that the adsorption amount increased with the increase of the reaction time,and reached a maximum at about 300 min for the TSFCD/Cr^(6+)system,and at about 240 min for DBFCM/Pb^(2+)system.The adsorption performance of TSFCD for Cr^(6+)and DBFCM for Pb^(2+)improved at higher temperature,and leveled off at 40℃ and 50℃,respectively.In addition,the removal rate of Cr^(6+)increased from 49.96%to 70.22%when the TSFCD dosage increased from 0.5 g/L to 3.5 g/L.Similarly,the removal rate of Pb^(2+)increased from 22.23%to 99.45%with the increase of DBFCM dosage from 0.5g/L to 5.0g/L.The adsorption processes of Pb^(2+)and Cr^(6+)were in line with the pseudo-second-order kinetic and the Langmuir isothermal model.