Synthesis of 2‐Thioxohydropyridine‐3‐Carbonitrile, 2‐Alkylthiopyridine,Thienopyridine, Pyrazolopyridine Derivatives and Their Theoretical Calculations

Cyanothioacetamide ( 1 ) reacted with but‐2‐enal ( 2 ) to give the corresponding 4‐methyl‐2‐sulfanylpyridine‐3‐carbonitrile ( 7 ) which was used as a good starting material for the synthesis of 1‐(3‐amino‐4‐methylthieno[2,3‐b]pyridin‐2‐yl)ethan‐1‐one ( 10 ), 3‐amino‐4‐methylthieno[2,3‐b]pyridine‐2‐carboxamide ( 15 ), 3‐amino‐4‐methylthieno[2,3‐b]pyridine‐2‐carboxylate ( 18 ) and 3‐amino‐4‐methylthieno[2,3‐b]pyridin‐2‐ylarylketone 25a‐c through its reactions with each of (1‐chloroacetone ( 8 ), 3‐chloropentane‐2,4‐dione ( 11 ) or ethyl 2‐chloro‐3‐oxo‐butanoate ( 19 )), 2‐chloroacetamide ( 13 ), ethyl 2‐chloroacetate ( 16 ) and 2‐bromo‐1‐arylethan‐ 1 ‐one 23a‐c , respectively. Considering the data of elemental analyses, IR, ¹HNMR, mass spectra and theoretical calculations, structures of the newly synthesized heterocyclic compounds were elucidated.     

A Novel Conversion of 2, 4‐Diaryl‐2, 3‐dihydro‐1 H‐1, 5‐benzodiazepines into 2, 4‐Diaryl‐3 H‐1, 5‐benzodiazepines

A novel conversion of 2, 4‐diaryl‐2, 3‐dihydro‐1 H‐1, 5‐benzodiazepins into 2, 4‐diaryl‐3 H‐1, 5‐benzodiazepines by the reaction with m‐chloroperbenzoic acid (MCPBA) was reported.     

Trans‐3,5‐dihydroperoxy‐3,5‐dimethyl‐1,2‐dioxalane/HBr System as New,Effective, Mild and Non‐toxic Reagent for Synthesis of 2‐Aryl‐1H‐benzothiazoles and 2‐Aryl‐1‐arylmethyl‐1H‐benzimidazoles

Ttrans‐3,5‐dihydroperoxy‐3,5‐dimethyl‐1,2‐dioxalane has been used as new, effective, solid, inexpensive and nontoxic oxidant for in situ generation of Br⁺ from HBr. This system has been applied as catalyst for synthesis of 2‐aryl‐1H‐benzothiazoles and 2‐aryl‐1‐arylmethyl‐1H‐benzimidazoles at room temperature in excellent yields and high purity.     

Darstellung,Kristallstrukturen, Schwingungsspektren und Normalkoordinatenanalysen der mer‐Trihalogeno‐tris‐Pyridin‐Osmium(III)Komplexe mer‐[OsX3Py3], X = Cl,Br, I

Synthesis, Crystal Structures, Vibrational Spectra, and Normal Coordinate Analyses of the mer ‐Trihalogeno‐tris‐Pyridine‐Osmium(III) Complexes mer‐[OsX₃Py₃], X = Cl, Br, I By reaction of the hexahalogenoosmates(IV) with pyridine and iso‐amylalcohol mer‐trihalogeno‐tris‐pyridine‐osmium(III) complexes are formed and purified by chromatography. X‐ray structure determinations on single crystals have been performed of mer‐[OsBr₃Py₃] (monoclinic, space group P2₁/n, a = 9.098(5), b = 12.864(5), c = 15.632(5) Å, β = 90.216(5)°, Z = 4) and mer‐[OsI₃Py₃] (monoclinic, space group P2₁/n, a = 9.0952(17), b = 13.461(4), c = 15.891(10), β = 91.569(5)°, Z = 4). The pyridine rings are twisted propeller‐like against the N₃ meridional plane with mean angles of 49° (Cl), 46° (Br), 44° (I). Based on the molecular parameters of the X‐ray structure determinations and assuming C₂ point symmetry, the IR and Raman spectra are assigned by normal coordinate analysis. Due to the stronger trans influence of pyridine as compared with the halide ligands for N'–Os–X ^· axes significantly different valence force constants are observed in comparison with symmetrically coordinated octahedron axes: f_d(OsCl) = 1.74, f_d(OsCl^·) = 1.49, f_d(OsBr) = 1.43, f_d(OsBr ^· ) = 1.18, f_d(OsI) = 0.99, f_d(OsI ^· ) = 0.96, f_d(OsN) between 1.96 and 2.07 and f_d(OsN') between 2.13 and 2.32 mdyn/Å.     

A Three‐Component One‐Pot Synthesis of Functionalized 5,5‐Dicyanocyclopenta‐1,3‐dienes from Arylidene­malononitriles,Activated Acetylenes,and KCN or KSCN

The reaction of dialkyl acetylenedicarboxylates with arylidenemalononitriles in the presence of KSCN in MeCN led to a mixture of dialkyl (3E)‐4‐aryl‐3‐(arylideneamino)‐5,5‐dicyanocyclopenta‐1,3‐diene‐1,2‐dicarboxylates and dialkyl 4‐aryl‐5‐cyanothiophene‐2,3‐dicarboxylates. When these reactions were performed in the presence of KCN, only the functionalized 5,5‐dicyanocyclopenta‐1,3‐dienes were obtained.     

Synthesis,Spectroscopy, and Structures of Mono‐ and Dinuclear Copper(I) Halide Complexes with 1,3‐Imidazolidine‐2‐thiones

Copper(I) halides with triphenyl phosphine and imidaozlidine‐2‐thiones (L ‐NMe, L ‐NEt, and L ‐NPh) in acetonitrile/methanol (or dichloromethane) yielded copper(I) mixed‐ligand complexes: mononuclear, namely, [CuCl(κ¹‐S‐L ‐NMe)(PPh₃)₂] ( 1 ), [CuBr(κ¹‐S‐L ‐NMe)(PPh₃)₂] ( 2 ), [CuBr(κ¹‐S‐L ‐NEt)(PPh₃)₂] ( 5 ), [CuI(κ¹‐S‐L ‐NEt)(PPh₃)₂] ( 6 ), [CuCl(κ¹‐S‐L ‐NPh)(PPh₃)₂] ( 7 ), and [CuBr(κ¹‐S‐L ‐NPh)(PPh₃)₂] ( 8 ), and dinuclear, [Cu₂(κ¹‐I)₂(μ‐S‐L ‐NMe)₂(PPh₃)₂] ( 3 ) and [Cu₂(μ‐Cl)₂(κ¹‐S‐L ‐NEt)₂(PPh₃)₂] ( 4 ). All complexes were characterized with analytical data, IR and NMR spectroscopy, and X‐ray crystallography. Complexes 2 – 4 , 7 , and 8 each formed crystals in the triclinic system with P$\bar{1}$ space group, whereas complexes 1 , 5 , and 6 crystallized in the monoclinic crystal system with space groups P2₁/c, C2/c, and P2₁/n, respectively. Complex 2 has shown two independent molecules, [(CuBr(κ¹‐S‐L ‐NMe)(PPh₃)₂] and [CuBr(PPh₃)₂] in the unit cell. For X = Cl, the thio‐ligand bonded to metal as terminal in complex 4 , whereas for X = I it is sulfur‐bridged in complex 3 .     

Synthesis,Reactions, Characterization and Biological Evaluation of 2,3′‐Bipyridine Derivatives (III)

1‐Pyridin‐3‐yl‐3‐(2‐thienyl of 2‐furyl)prop‐2‐en‐1‐ones 1a , 1b reacted with 2‐cyanoethanethioamide 2 to afford the corresponding 4‐(thiophen‐2‐yl or furan‐2‐yl)‐6‐sulfanyl‐2,3′‐bipyridine‐5‐carbonitriles 3a , 3b . The synthetic potentiality of compounds 3a , 3b were investigated in the present study via their reactions with several active halogen containing compounds 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4h , 5 , 5a , 5b . Our aim here is the synthesis of 4‐(2‐thienyl or 2‐furyl)‐6‐pyridin‐3‐ylthieno[2,3‐b]pyridin‐3‐amines 6a , 6b , 6c , 6d , 6e , 6g , 6h , 6i , 6j , 6k , 6l , 6m , 6n ,via 6‐(alkyl‐thio)‐4‐(2‐thienyl or 2‐furyl)‐2,3′‐bipyridine‐5‐carbonitriles 5a , 5b , 5c , 5d , 5e , 5i , 5j , 5k , 5l , 5m . The structures of all newly synthesized heterocyclic compounds were elucidated by considering the data of IR, ¹H‐NMR, mass spectra, as well as that of elemental analyses. Anti‐cancer, anti‐Alzheimer, and anti‐COX‐2 activities were investigated for all the newly synthesized heterocyclic compounds.     

The First One‐Pot,Solvent‐Free,Microwave‐Accelerated,Three‐Component Synthesis of Spirothiazolidin‐4‐ones via Staudinger/Aza‐Wittig Coupling/Cyclization

An efficient and rapid, solvent‐free, microwave‐accelerated, one‐pot, three‐component protocol for the synthesis of spirothiazolidin‐4‐ones from organic azides is reported for the first time via Staudinger/aza‐Wittig coupling/cyclization. The solvent‐free approach overcomes the limitations associated with the prevailing solution‐phase methodologies in the case of amines. In particular, its novelty is that it eradicates the vital limitation, i.e., the accumulation of H₂O (by‐product), which is known to affect the yield and rate of the reaction, thus affording the spirothiazolidin‐4‐ones in short reaction times in excellent yields.     

Isocyanide‐Based Three‐Component Synthesis of Highly Substituted 1,6‐Dihydro‐6,6‐dimethylpyrazine‐2,3‐dicarbonitrile, 3,4‐Dihydrobenzo[g]quinoxalin‐2‐amine,and 3,4‐Dihydro‐3,3‐dimethyl‐quinoxalin‐2‐amine Derivatives

A novel and efficient isocyanide‐based multicomponent reaction between alkyl or aryl isocyanides 1 , 2,3‐diaminomaleonitrile ( 2 ), naphthalene‐2,3‐diamines ( 6 ) or benzene‐1,2‐diamine ( 9 ), and 3‐oxopentanedioic acid ( 3 ) or Meldrum's acid ( 4 ) or ketones 7 was developed for the ecologic synthesis, at room temperature under mild conditions, of 1,6‐dihydropyrazine‐2,3‐dicarbonitriles 5a – 5f in H₂O without using any catalyst, and of 3,4‐dihydrobenzo[g]quinoxalin‐2‐amine and 3,4‐dihydro‐3,3‐dimethyl‐quinoxalin‐2‐amine derivatives 8a – 8g and 10a – 10e , respectively, in the presence of a catalytic amount of p‐toluenesulfonic acid (TsOH) in EtOH, in good to excellent yields (Scheme 1).     

Design,Synthesis, and Insecticidal Activity of 1,5‐Diphenyl‐1‐pentanone Analogues

Three series of novel 1,5‐diphenyl‐1‐pentanone derivatives were designed and synthesized. Their structures were characterized by IR, ¹H NMR techniques, and elemental analysis. The insecticidal activities of the new compounds were preliminarily evaluated. The bioassay results indicated that the compounds X11 – X30 displayed better aphicidal activity against Aphis gossypii than compounds X1 – X10 and the lead compound (E)‐1,5‐diphenyl‐1‐penten‐1‐one ( A ). The inhibitory rates of compounds X6 and X29 were 100% against Plutella xylostella (L.) at 600 mg·L^?1. Compounds X12 , X13, X19 , X24, X25 , X26 and X27 showed higher insecticidal activity against Tetranychus cinnabarinus (Boisduval) at 600 mg·L^?1 than the lead compound ( A ).     

Simple,Efficient, and Catalyst‐Free Synthesis of (2‐Amino‐4H‐1‐benzopyran‐4‐yl)phosphonates in Polyethylene Glycol

Several (2‐amino‐4H‐1‐benzopyran‐4‐yl)phosphonates were efficiently synthesized by employing a multicomponent protocol involving a salicylaldehyde, malononitrile or ethyl cyanoacetate, and a trialkyl phosphite in polyethylene glycol. The latter could be recovered and re‐used. No additional solvent or catalyst was required. To the best of our knowledge, this is the first report of the one‐pot preparation of (2‐amino‐4H‐1‐benzopyran‐4‐yl)phosphonic acid dimethyl esters.     

Synthesis,Crystal Structure,Hydrogen Bonding,and Thermal Behavior of a Three‐Dimensional CuII‐benzene‐1,2,4,5‐tetracarboxylate Templated by 1,9‐Diaminononane

Triclinic single crystals of Cu₄(H₃N–(CH₂)₉–NH₃)(OH)₂[C₆H₂(COO)₄]₂ · 5H₂O were prepared in aqueous solution at 80 °C in the presence of 1,9‐diaminononane. Space group P$\bar{1}$ (no. 2) with a = 1057.5(2), b = 1166.0(2), c = 1576.7(2) pm, α = 106.080(10)°, β = 90.73(2)° and γ = 94.050(10)°. The four crystallographic independent Cu²⁺ ions are surrounded by five oxygen atoms each with Cu–O distances between 191.4(3) and 231.7(4) pm. The connection between the Cu²⁺ coordination polyhedra and the [C₆H₂(COO)₄]^4– anions yields three‐dimensional framework with negative excess charge and wide centrosymmetric channel‐like voids. These voids extend parallel to [001] with the diagonal of the nearly rectangular cross‐section of approximately 900 pm. The channels of the framework accommodate [H₃N–(CH₂)₉–NH₃]²⁺ cations and water molecules, which are not connected to Cu²⁺. The nonane‐1,9‐diammonium cations adopt a partial gauche conformation. Thermoanalytical measurements in air show a loss of water of crystallization starting at 90 °C and finishing at approx. 170 °C. The dehydrated compound is stable up to 260 °C followed by an exothermic decomposition yielding copper oxide.     

Design,Synthesis, Antifungal Activities and SARs of (R)‐2‐Aryl‐4,5‐dihydrothiazole‐4‐carboxylic Acid Derivatives

Based on the structure of natural product 2‐aryl‐4,5‐dihydrothiazole‐4‐carboxylic acid, a series of novel (R)‐2‐aryl‐4,5‐dihydrothiazole‐4‐carboxylic acid derivatives were designed and synthesized. Their structures were characterized by ¹H NMR, ¹³C NMR and HRMS. The single crystal structure of compound 9b was determined by X‐ray diffraction analysis. The antifungal activities were evaluated for the first time. The bioassay results indicated that most compounds exhibited moderate to good antifungal activities. The antifungal activities of compound 13a (against Cercospora arachidicola Hori), 13d (against Alternaria solani), and 16e (against Cercospora arachidicola Hori) were 61.9%, 67.3% and 61.9%, respectively, which are higher than those of the commercial fungicides chlorothalonil and carbendazim. Moreover, compound 13d exhibited excellent antifungal activities against 7 kinds of the fungi tested (66.7%, 77.3%, 63.0%, 87.9%, 70.0%, 70.0% and 80.0% at 50 µg?mL). Therefore, 13d can be used as a new lead structure for the development of antifungal agents.     

Synthesis,solid‐state,and charge‐transport properties of conjugated polythiophene‐S,S‐dioxides

An alkylated semiconducting polymer comprising alternating bithiophene‐[all]‐S,S‐dioxide and aromatic monothiophene units in the polymer backbone was synthesized with the intent of modifying the energy gap and lowest unoccupied molecular orbital for use as a stable n‐type semiconductor. Films spun from this semiconducting polymer were characterized utilizing X‐ray scattering, near edge X‐ray absorption fine structure spectroscopy, ultraviolet photoelectron spectroscopy, and thin‐film field effect transistors to determine how oxidation of the thiophene ring systems impacts the structural and electronic properties of the polymer. The thiophene‐S,S‐dioxide polymers have lower optical and electrical band gaps than corresponding thiophene polymers. X‐ray scattering results indicate that the polymers are well ordered with the π–π stacking distances increased by 0.4 Å relative to analogous thiophene polymers. The electrical stability of these polymers is poor in transistors with a drop in the field effect mobility by approximately one order of magnitude upon addition of just 5% of the thiophene‐S,S‐dioxide unit in a copolymer with thiophene. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2013     

Syntheses,Structures, and Electrochemical Properties of Two Bis‐triazole‐bis‐amide‐based Copper(II) Pyridine‐2,3‐dicarboxylate Coordination Polymers

Abstract. Two bis‐triazole‐bis‐amide‐based copper(II) pyridine‐2,3‐dicarboxylate coordination polymers (CPs), [Cu(2,3‐pydc)(dtb)_0.5(DMF)] · 2H₂O ( 1 ) and [Cu(2,3‐pydc)(dth)_0.5(DMF)] · 2H₂O ( 2 ) (2,3‐H₂pydc = pyridine‐2,3‐dicarboxylic acid, dtb = N,N′‐bis(4H‐1,2,4‐triazole)butanamide, and dth = N,N′‐bis(4H‐1,2,4‐triazole)hexanamide), were synthesized under solvothermal conditions. CPs 1 and 2 show similar two‐dimensional (2D) structures. In 1 , the 2,3‐pydc anions bridge the Cu^II ions into a one‐dimensional (1D) chain. Such 1D chains are linked by the dtb ligands to form a 2D layer. The adjacent 2D layers are extended into a three‐dimensional (3D) supramolecular architecture by hydrogen‐bonding interactions. The electrochemical properties of 1 and 2 were investigated.     

Syntheses,antitumor activities,and antiangiogenesis of exo‐3,6‐epoxy‐1,2,3,6‐tetrahydrophthalimidoethanoyl‐ 5‐fluorouracil and its polymers

A new monomer, exo‐3,6‐epoxy‐1,2,3,6‐tetrahydrophthalimidoethanoyl‐5‐fluorouracil (ETFU), was synthesized by the reaction of exo‐3,6‐epoxy‐1,2,3,6‐tetrahydrophthalimidoethanoyl chloride (ETPC) and 5‐fluorouracil (5‐FU). The homopolymer of ETFU and its copolymers with acrylic acid (AA) and vinyl acetate (VAc) were prepared via photopolymerizations with 2,2‐dimethoxy‐2‐phenylacetophenone at 25 °C for 48 h. The structures of the synthesized monomer and polymers were identified by Fourier transform infrared, ¹H NMR, and ¹³C NMR spectroscopy and elemental analysis. The ETFU contents in poly(ETFU‐co‐AA) and poly(ETFU‐co‐VAc) were 26 mol % and 26 mol %, respectively. The number‐average molecular weights of the polymers, as determined by gel permeation chromatography, ranged from 5600 to 17,000. The in vitro cytotoxicities of 5‐FU and the synthesized samples against mouse mammary carcinoma and human histiocytic lymphoma cancer cell lines increased in the following order: ETFU > 5‐FU > poly(ETFU‐co‐AA) > poly(ETFU) > poly(ETFU‐co‐VAc). The in vivo antitumor activities of the polymers against Balb/C mice bearing the sarcoma 180 tumor cells were greater than those of 5‐FU at all doses tested. The inhibitions of the samples for SV40 DNA replication and antiangiogenesis were much greater than the inhibition of the control. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4272–4281, 2000     

Synthesis of 4‐fluoroalkyl‐2H‐pyrido [1, 2‐a] pyrimidin‐2‐ones from 2, 2‐dihydropolyfluoroalkanoic acids

In the presence of N, N′‐dicyclohexylcarbodiimide, 2‐aminopyridine and its derivatives (2) condensed with 2, 2‐di‐hydropolyfluoroalkanoic adds (1) to give the corresponding amides. Subsequent intramolecular Micheal addition‐elimination reactions of the fluorine‐containing amides under basic conditions gave 4‐fluoroalkyl‐2H‐pyrido[1,2‐a]pyrimidin‐2‐ones (3) in good yields.