Key Intermediates: A Simple and Highly Selective Synthesis of 5-<i>Amino</i>-1-<i>aryl</i>-1<i>H</i>-<i>pyrazole</i>-4-<i>carbonitriles</i>for Applications in the Crop Protection

A series of six pyrazoles was synthesized by Michael-type addition reaction. The molecules 5-amino-1-aryl-1H-pyrazole-4-carbonitrile (3a-f) were synthesized from (ethoxymethylene)malo-nonitrile (1) and fluorinated and non-fluorinated aryl hydrazines (2a-f) using ethanol and fluorinated ethanol as solvents at reflux. An excellent regio-selectivity was found when pyrazole derivatives were formed as an exclusive product. No other regioisomer or uncyclised hydrazide was observed. Their structures were confirmed by spectroscopy data (1H, 13C, 19F, COSY (correlation spectroscopy), HSQC (heteronuclear single-quantum correlation spectroscopy) and HMBC (heteronuclear multiple-bond correlation spectroscopy);MS (mass-spectrometry). The yields ranged from good to excellent (47% - 93%) under mild reaction conditions. It would indicate a high selectivity in the one-step work procedure. These products (3a-f) and derivatives have a potential academic and industrial use as key intermediates, in special, for application in crop protection.

A Two-dimensional Metallic Oxide Constructed from Molybdenum Clusters and Ag(Ⅰ)-[3-(2-pyridyl)-pyrazole] Cationic Coordination Components

A new polyoxomolybdate compound [Ag 3 （HL） 4 ]（PMo 12 O 40）] 1 （HL=3-（2-pyridyl）pyrazole） has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction,elemental analyses,TG and IR spectroscopy.The compound crystallizes in triclinic,space group P1 with a=10.375（3）,b=12.076（3）,c=13.196（4）,α=84.170（4）,β=71.961（3）,γ=86.326（4）°,V=1563.1（7）3,C 32 H 28 Ag 3 Mo 12 N 12 O 40 P,M r=2726.52,D c=2.897 g/cm 3,μ（MoKα）=3.366 mm 1,F（000）=1284,Z=1,the final R=0.0587 and wR=0.1312 for 4139 observed reflections （I 2σ（Ⅰ））.X-ray diffraction analyses reveal that the PMo 12 O 40 3clusters in compound 1 are linked by four Ag 3 （HL） 4 3＋ units via the terminal oxygen atoms to form a two-dimensional architecture.The symmetrical unit of Ag 3 （HL） 4 3＋ exhibits two distinct Ag（Ⅰ） environments：a two-coordinate {AgN 2 } site and a five-coordinate {AgN 3 O 2 } site which links to two molybdate clusters.

Synthesis and Crystal Structure of a Polyoxomolybdate Framework Modified by Mn-L Units(L=3-(2-Pyridyl)pyrazole)

A new polyoxomolybdate compound,namely {[MnII（L）（4,4？-Hbipy）（H2O）2]2 [Mo5O15（PO4）2]}.2H2O 1（L = 3-（2-pyridyl）pyrazole,4,4＇-Hbipy = protonated 4,4＇-bipyridine）,was designed and synthesized under hydrothermal conditions.Single-crystal X-ray diffraction analysis result reveals that the [Mo5O15（PO4）2]6-cluster in compound 1 links to two MnII cations via the oxygen of PO43-,which is further coordinated by one 3-（2-pyridyl）pyrazole,one 4,4＇-Hbipyridine,and two water molecules.

A Two-dimensional Metallic Oxide Constructed from Molybdenum Clusters and Zn(Ⅱ)-[3-(2-pyridyl)pyrazole] Cationic Coordination Components

A new polyoxomolybdate compound [Zn（HL）2（Mo8O26）（4,4＇-Bipy）]·（4,4＇-Bipy） （HL = 3-（2-pyridyl）pyrazole, 4,4＇-Bipy = 4,4＇-bipyridine） 1 has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction, elemental analyses, TG and IR spectroscopy. The compound crystallizes in monoclinic, space group C2/c with a = 18.060（4）, b = 13.870（3）, c = 19.360（4） A, β = 93.50（3）°, V = 4840.5（17） 3, C36H30Mo8N10O26Zn, Mr = 1851.59, Dc = 2.541 g/cm^3, μ（MoKα） = 2.589 mm·1, F（000） = 3560, Z = 4, the final R = 0.0328 and wR = 0.0870 for 4005 observed reflections （I 〉 2σ（I））. X-ray diffraction analyses reveal that compound 1 is constructed from Mo8O264-units linked by Zn（HL）22＋ and 4,4＇-Bipy. Mo8O264-is connected by Zn（HL）2^2＋ via terminal oxygen atoms along the [010] axis forming chains, which are further linked by 4,4＇-Bipy along the [001] axis forming a two-dimensional network structure.

Synthesis, Structural Characterization and Antimicrobial Activity of a Novel Cobalt(II) Complex Based on 3-Methyl-1-Phenyl-4-(2-Thienoyl)-Pyrazol-5-One

New cobalt(II) complex, [Co(O2C15H11N2S)2(OH2)2]∙2H2O (1∙2H2O), has been synthesized upon reaction of cobalt chloride hexahydrate (Co(Cl)2∙6H2O) with 3-methyl-1-Phenyl-4-(2-thienoyl)-pyrazol-5-one (referred as HL) in ethanol at room temperature. Single crystal X-ray diffraction (XRD), spectroscopic methods, and microelemental analyses were used to characterize 1∙2H2O. Compound 1∙2H2O crystallizes in the orthorhombic crystal system with a Pbca space group and with the cobalt atom being pseudo-octahedral coordinated. The broth microdilution technique was used to screen the free ligand (HL) and the complex (1∙2H2O) for antimicrobial activities. HL has a low activity (MIC > 100 μg/mL) on all microorganisms, whereas compound 1∙2H2O displayed moderate activity (10 ∙2H2O exhibited bactericidal and fungicidal activity respectively on all the bacteria and yeasts tested. These findings reveal that the antimicrobial activity of HL was enhanced upon coordination to Co(II) ion against all microorganisms (bacteria and fungus).

A One-dimensional Metallic Oxide Constructed from Molybdenum Clusters and Mn(Ⅱ)-[3-(2-pyridyl) pyrazole] Cationic Coordination Components

A new polyoxomolybdate compound [Mn II （L） 2 （Mo 8 O 26） 0.5 ] 2n （1,L=3-（2-pyridyl）pyrazole） has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction,elemental analyses,TG and IR spectroscopy.The compound crystallizes in the triclinic system,space group P1 with a=10.063（4）,b=11.554（5）,c=11.554（5）,α=88.89,β=74.839（4）,γ=74.839（4）o,V=1249.8（9） 3,C 16 H 14 MnMo 4 N 6 O 13,M r=937.03,D c=2.490 g/cm 3,μ（MoKα）=2.521 mm 1,F（000）=898,Z=2,the final R=0.0390 and wR=0.0970 for 4000 observed reflections （I 2σ（Ⅰ））.Single-crystal X-ray diffraction analysis results reveal that compound 1 owns a chain structure based on β-[Mo 8 O 26 ] 4anions,which are linked by Mn II （L） 2 units via the terminal oxygen atoms.

Synthesis, Structural Characterization and Antimicrobial Activity of a Novel Cobalt(II) Complex Based on 3-Methyl-1-Phenyl-4-(2-Thienoyl)-Pyrazol-5-One

New cobalt(II) complex, [Co(O2C15H11N2S)2(OH2)2]∙2H2O (1∙2H2O), has been synthesized upon reaction of cobalt chloride hexahydrate (Co(Cl)2∙6H2O) with 3-methyl-1-Phenyl-4-(2-thienoyl)-pyrazol-5-one (referred as HL) in ethanol at room temperature. Single crystal X-ray diffraction (XRD), spectroscopic methods, and microelemental analyses were used to characterize 1∙2H2O. Compound 1∙2H2O crystallizes in the orthorhombic crystal system with a Pbca space group and with the cobalt atom being pseudo-octahedral coordinated. The broth microdilution technique was used to screen the free ligand (HL) and the complex (1∙2H2O) for antimicrobial activities. HL has a low activity (MIC > 100 μg/mL) on all microorganisms, whereas compound 1∙2H2O displayed moderate activity (10 ∙2H2O exhibited bactericidal and fungicidal activity respectively on all the bacteria and yeasts tested. These findings reveal that the antimicrobial activity of HL was enhanced upon coordination to Co(II) ion against all microorganisms (bacteria and fungus).

Synthesis and Crystal Structure of 7-Ethoxycarbonyl-2-methyl-6-methylthio-1H-imidazo[1,2-b]pyrazole

The title compound 7-ethoxycarbonyl-2-methyl-6-methylthio-lH-imidazo[1,2-b]- pyrazole （Mr = 239.29） was synthesized and structurally characterized by IR, ^1H NMR and single-crystal X-ray diffraction. It belongs to the triclinic system, space group P1, with a =8.0461（10）, b = 8.5534（11）, c = 9.5605（12）А,α= 64.804（2）,β= 74.231（2）, γ= 76.885（2）°, V = 568.27（12）А^3, Z = 2,Dc= 1.398 g/cm^3,μ= 0.274 nunl, F（000） - 252, the final R = 0.0454 and wR = 0.1261. A total of 3360 reflections were collected, of which 2466 were independent （R_int = 0.0138） and 2154 were observed with I〉2σ（I）.

Synthesis and Herbicidal Activity of 5-Heterocycloxy-3-substituted-1-(3-trifluoromethyl)phenyl-1H-pyrazole

The authors synthesized a series of novel 5-heterocycloxy-3-substituted-1-（3-trifluoromethyl）phenyl-1H- pyrazole derivatives. Herbicidal activities of the two intermediate compounds and thirteen target compounds were evaluated via Brassica napus and Echinochloa crusgalli（L.） Beauv tests. Bioassay results show that some of the compounds exhibit better inhibiting activities against Brassica napus and some of the compounds exhibit bleaching activities against Echinochloa crusgalli（L.） Beauv at 100 μg/mL.

Use of Solid-Supported Reagents towards Synthesis of 2-Arylbenzoxazole, 3, 5-Diarylisoxazole and 1, 3, 5-Triarylpyrazole

Herein we report a convenient and efficient synthesis of 2-Arylbenzoxazole from the Schiff’s bases of 2-Aminophenol, 3, 5-Diarylisoxazole from α, β-unsaturated ketoxime and 1,3,5-Triarylpyrazole from 2-pyrazoline and N-Arylhydrazone by using milder, less toxic and less expensive-NBS-SiO2, KMnO4-Al2O3, PCC-SiO2 and ACC-Al2O3 as solid-supported oxidizing agents at room temperature. Within the framework of Green Chemistry, the use of solid supported reagents has many advantages such as 1) they are easy to remove from reactions by filtration 2) excess reagents can be used to drive the reaction without introducing any difficulties in purification 3) such solid-supported reagents react differently, mostly more selectively, than their unbound counterparts and 4) toxic, noxious and explosive chemicals are handled more safely when contained on solid support.

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.

Synthesis, Crystal Structure, Fluorescent Property and DFT Calculations of a New Zn(Ⅱ) Complex Based on 3-(2-Pyridyl)-5-(4-pyridyl)-1H-1,2,4-triazole

A new coordination compound Zn（2,4＇-bpt）2（H2O）（1） based on the versatile ligand 2,4＇-Hbpt（2,4？-Hbpt = 3-（2-pyridyl）-5-（4-pyridyl）-1H-1,2,4-triazole） was prepared by hydrothermal reactions. The structure of complex 1 has been characterized by X-ray single-crystal diffraction, elemental analysis, X-ray powder diffraction, IR spectrum analysis and thermogravimetric analysis. Single-crystal X-ray diffraction analysis indicates that the complex belongs to monoclinic system, space group C2/c with a = 23.877（3）, b = 0.7483（9）, c = 1.2492（2） A, b = 92.681（2）°, V = 2230.6（4） A^3, Z = 4, Dc = 1.572 g/cm^3, m = 1.143 mm^-1, Mr = 527.85 and F（000） = 1080. The final R = 0.0581 and wR = 0.0898 with I 〉 2s（I）. 1 is a 0D motif which is connected by hydrogen bonds to form a corrugated 1D pattern. In addition, 1 shows strong photoluminescent emissions in the solid state at room temperature which can be used as potential optical materials. Theoretical calculations based on density functional theory（DFT） were employed in order to explicate the stability and chemical reactivity of 2,4＇-Hbpt with different conformations. The results indicated that conformation I is more stable and prior to coordination in the reactions.

Three New Zn(Ⅱ)/Cd(Ⅱ) Coordination Polymers Constructed with 2-Mercaptonicotinic Acid and 1,2-Di(4-pyridyl)ethylene: Syntheses and Structure Analysis

Three new Zn（Ⅱ）/Cd（Ⅱ） coordination polymers based on 2-mercaptonicotinic acid （H2mna） with 1,2-di（4-pyridyl）ethylene （dpe） introduced as a bridging ligand have been synthesized via hydrothermal method and structurally characterized by single-crystal X-ray diffraction as well as elemental analysis and IR. As reported in this paper, [Zn2（dpe）0.5（mna）2] （1） can be classified as a two-dimensional layer structure in which the 1D chain composed of Zn（Ⅱ） and mna ligands is bridged by dpe ligands, while the complex named [Zn4（dpe）4（mna）4] （2） is a tetra-nuclear cluster compound. These two compounds are further extended to three-dimensional structures by hydrogen bonds along with C–H…π and π…π interactions. Compound 3 with general formular [Cd2（dpe）0.5（mna）2]·H2O belongs to a three-dimensional porous structure in which the 2D metal layers formed by the coordination of Cd（Ⅱ） and mna ligands are connected with the bridging of dpe ligands.

Hydrothermal Syntheses and Crystal Structures of Six Complexes Constructed from 1,3,5-Benzenetricarboxylic Acid and 4'-(4-Pyridyl)-2,2':6',2''-terpyridine Mixed Ligands

Six new transition metal complexes, [Zn（HBTC）（PYTPY）]n·n PYTPY（1）, [Cu（HBTC）（PYTPY）]n·n PYTPY（2）, [Co（HBTC）（PYTPY）]n·n DMF（3）, [Mn（HBTC）（PYTPY）]n·n DMF（4）, [Cd（HBTC）（PYTPY）（H2O）]n·2nH2O（5）, and [Co（HBTC）（PYTPY）（H2O）2]（6）,（H3BTC = 1,3,5-benzenetricarboxylic acid, PYTPY = 4＇-（4-pyridyl）-2,2＇：6＇,2＇＇-terpyridine, DMF = N,N？-dimethylformamide）, have been synthesized and characterized by elemental analysis, IR and X-ray single-crystal diffraction. Complexes 1~5 all feature one-dimensional chain structures, and complex 6 exhibits a zero-dimensional structure. Complexes 1~5 present three-dimensional（3D） supramolecular frameworks via π-π stacking interactions, whenas 6 has also a 3D supramolecular structure assembled by hydrogen bonding. Meanwhile, complexes 1 ~ 6 exhibit the thermal stabilities and photoluminescent properties.

Catalytic Kinetic on the Thermal Decomposition of Ammonium Perchlorate with a New Energetic Complex Based on 3,5-Bis(3-pyridyl)-1H-1,2,4-triazole

A new energetic complex,[Co（3,3？-Hbpt）（Htm）]·H_2O（1,3,3？-Hbpt = 3,5-bis（3-pyridyl）-1H-1,2,4-triazole and H_3tm = trimesic acid）,has been synthesized by hydrothermal reactions and characterized by single-crystal X-ray diffraction,elementary analysis,IR spectroscopy,thermogravimetric analysis and X-ray powder diffraction. Single-crystal X-ray diffraction indicates that the complex belongs to triclinic system,space group P 1 with a = 10.0911（1）,b = 10.2573（1）,c = 10.6393（1） ？,α = 103.793（2）,β = 101.041（2）,γ = 107.918（3）o,V = 974.9（2） ？~3,Z = 2,D_c = 1.732 g·cm-3,μ = 0.941 mm^（-1）,M_r = 508.31,F（000） = 518,the final R = 0.0523 and wR = 0.0935 with I 〉 2σ（I）. In the title complex,Co（Ⅱ） ions are connected by Htm2-anions generating 1D ladder-like chains which are linked by 3,3？-Hbpt to form 1D cages. In addition,the thermal decomposition of ammonium perchlorate（AP） with complex 1 was explored by differential scanning calorimetry（DSC）. AP is completely decomposed in a shorter time in the presence of complex 1,and the decomposition heat of the mixture is 2.531 kJ·g^（-1）,significantly higher than that of pure AP. By Kissinger＇s method,the ratio of Ea/ln（A） is 11.05 for the mixture,which indicates that complex 1 shows good catalytic activity toward the AP decomposition.

Syntheses, Structures and Photoluminescence of the Cadmium(Ⅱ) and Copper(Ⅱ) Complexes Based on 4'-(4''-Pyridyl)-2,2':6',2''-terpyridine and 1,4-Benzenedicarboxylic Acid Ligands

Two new metal-organic complexes [Cd2（1,4-BDC）（4-pytyp）（H2O）4]·（1,4-BDC）（1） and [Cu2（1,4-BDC）（4-pytyp）2（H2O）2]·（1,4-BDC）·8H2O（2）（4-pytyp = 4＇-（4＇＇-pyridyl）-2,2＇：6＇,2＇＇-terpyridine, 1,4-H2 BDC = 1,4-benzenedicarboxylic acid） have been synthesized under hydrothermal conditions and characterized by elemental analysis, infrared analysis and X-ray single-crystal diffraction. The scrutiny of single-crystal structure reveals that complex 1 forms to a 3D supramolecular network linked by π-π stacking interactions and hydrogen bonds. X-ray diffraction analysis reveals that complex 2 exhibits a 3D supramolecular network linked through complicated hydrogen bonds. The thermogravimetric analysis and photoluminescent properties of 1 and 2 are discussed in detail.

Synthesis, Crystal Structure and Biological Activity of 4-Amino-2,4-dihydro-5-((3,5-dimethyl-1H-pyrazol-1-yl)methyl)-3H-1,2,4-triazole-3-thione Schiff Base

The target compound 1,2,4-triazole Schiff base containing pyrazole ring was synthesized by 4-amino-2,4-dihydro-5-（（3,5-dimethyl- lH-pyrazol-1-yl）methyl）-3H-1,2,4-triazole-3-thione and 3,4,5-trimethoxy benzaldehyde.The structure was confirmed by IR,~1H NMR,H RMS,elemental analysis and single-crystal X-ray diffraction.The crystal belongs to the triclinic system,space group P1 with a = 7.8772（17）,b = 8.2986（18）,c = 15.392（3） A,α= 93.360（4）,β= 94.609（4）,γ= 93.584（4）°,C（18）H（22）N6O3S,Mr= 402.47,V= 998.9（4） A^3,Z= 2,F（000） = 422,Dc =1.335 g/cm^3,μ= 0.194 mm^（-1）,the final R = 0.0533 and wR = 0.1329 for 3517 observed reflections with I 2σ（I）.The preliminary bioassay results indicate that the target compound has good fungicidal activity against Gibberlla nicotiancola in EC50 value and F.O.f.sp.niveum in EC（95） value.

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.

Insight into the Detailed Mechanism of HRh(CO)(PPh_3)_3 Catalyzed Hydroformylation of 1-Phenyl-1-(3-pyridyl)ethene:A DFT Study

Density functional calculations have been used to study the mechanism of 1-phenyl-1-（3-pyridyl）ethene hydroformylation using rhodium catalyst.Our calculations reveal that the rate-determining step is the oxidative addition of hydrogen molecule and the preferred path is the one involving ts3ans for the lowest activation free-energy （ΔrGa）,63.8 kJ/mol.This reaction is demonstrated to be strong exothermic by-96.6 kJ/mol of branched products and-98.2 kJ/mol of linear products.And the predominant product is the linear 3-phenyl-3-（3-pyridal）propanal （pr-ns） determined by both thermodynamics and kinetics.These results are in agreement with the practicality experimental studies.

A Mini-Review 5-Amino-N-Substituted Pyrazoles as Building Blocks for Bioactive Molecules

In this review a five-membered heterocyclic ring having two adjacent nitrogen atoms known as Pyrazole, we have framed 5-amino-N-substituted pyrazoles in particular focusing on its substantial role as a building block and starting materials for producing enormous heterocyclic skeletons. The existence of this moiety in larger compounds renders them to expose medicinal, pharmacological and biological therapeutic activities. Enormous drugs contain 5-amino-N-substituted pyrazoles such as celecoxib anti-inflammatory, antipsychotic, anti-obesity, analgesic, and antidepressant. We reported various routes of synthesis and the use of these compounds.