Synthesis of benzonorcaradienes by gold(I)-catalyzed [4+3] annulation

A formal [4 + 3]-annulation of vinyl arenes and diynyl propargyl esters is described. A mechanism involving cationic phosphinegold(I)-catalyzed tandem cyclopropanation/hydroarylation to produce the benzonorcaradiene products is proposed. In accord with this mechanism, the alkynyl cyclopropane can also be prepared with excellent regio- and diastereocontrol.     

Elektrochemische synthesen metallorganischer verbindungen III. Darstellung und umwandlung von π-cyclooctenyl-1,5-cyclooctadiencobalt

By electrolysis of cobalt(II)-acetylacetonate in the presence of 1,5-cyclooctadiene there is obtained π-cyclooctenyl-1,5-cyclooctadienecobalt (I). By heating of I to 60° in 1,5-cyclooctadiene, π-bicyclo[3.3.0]octadienyl-(1,5-cyclooctadiene)cobalt (II) and cyclooctene are formed.     

1,3-Dipolar cycloaddition between a metal-azide (Ph3PAuN3) and a metal-acetylide (Ph3PAuC≡CPh): an inorganic version of a click reaction

This report describes the synthesis and characterization of 1,5-bis-triphenylphosphinegold(I) 1,2,3-triazolate (3((1,5))). The synthesis of the dinuclear complex 3((1,5)) is achieved via an unprecedented inorganic click (iClick) reaction between the metal-azide PPh(3)AuN(3) (1) and the metal-acetylide PPh(3)Au-C≡CPh (2). Characterization of 3((1,5)) includes multinuclear NMR spectroscopy, combustion analysis, and single crystal X-ray crystallography. Experimental characterization is complemented with density-functional-theory (DFT) calculations which indicate the 1,4-isomer 3((1,4)) is less stable by 3.3 kcal mol(-1). The energetic difference lies primarily in the ability of the phenyl group in the 4-position of 3((1,5)) to lie coplanar with the triazolate to create a delocalized π-bonding HOMO orbital.     

2-甲基-1,5-苯并硫氮杂的基态和激发态反应的研究III:2-甲基-1,5-苯并硫氮杂4-(5H)-酮与-4-甲基-1,5-苯并硫氮杂-2(3H)-酮间的互变异构

用化学反应和光谱分析证实了2-甲基(1,5)苯并硫氮杂环庚三烯-4(5H)-酮和4-甲基(1,5)苯并硫氮杂环庚三烯-2(3H)-酮是作为互变异构混合物存在的.     

Raman spectrum of 1,5-hexadien-3-yne

Summary In the liquid phase, 1,5-hexadien-3-yne apparently exists as a mixture of two isomers, namely cis (I) and trans (II) forms with (I) predominating.     

Synthesis and X-ray structures of water-soluble tris(hydroxymethyl)phosphine complexes of rhodium(I)

The water-soluble Rh(I)-THP complexes: RhCl(1,5-cod)(THP) (), [Rh(1,5-cod)(THP)(2)]Cl (), RhCl(THP)(4) (), and trans-RhCl(CO)(THP)(2) () have been synthesized and characterized, where THP = P(CH(2)OH)(3); - are the first potentially useful entries into Rh(I)-THP chemistry, while and are the first structurally characterized Rh(I)-THP complexes.     

Synthesis and Structure of a 3D Manganese Coordination Polymer with 1,3-Bis（benzimidazol-1-ylmethyl）-2,4,6-trimethylbenzene and 1,5-Naphthalenedisulfonate

The organic-inorganic hybrid polymer [Mn(mbbimb)2(1,5-nds)]n 1 has been synthesized using 1,5-naphthalenedisulfonate (1,5-nds) and 1,3-bis(benzimidazol-1-ylmethyl)- 2,4, 6-trimethylbenzene (mbbimb) with Mn(OAC)2·4H2O in solvothermal reaction. The X-ray crystal structure analysis indicates that 1 crystallizes in monoclinic, space group C2/c with a = 21.3546(17), b = 11.8841(7), c = 22.1588(16) , β = 108.058(3)°, C60H54MnN8O6S2, Mr = 1102.17, Ζ = 4, V = 5346.5(7) 3, Dc = 1.369 g/cm3, μ = 0.386 mm-1, F(000) = 2300, S = 1.091, R = 0.0634 and wR = 0.1559 for 4641 observed reflections (I > 2σ(I)). The Mn center is six-coordinated to furnish a distorted octahedral geometry, and the overall framework is a 6-con- nected 3D net.     

Cytotoxicities and Topoisomerase I Inhibitory Activities of 2‐[2‐(2‐Alkynylphenyl)ethynyl]benzonitriles, 1‐Aryldec‐3‐ene‐1,5‐diynes,and Related Bis(enediynyl)arene Compounds

The activities of a series of acyclic enediynes, 2‐(6‐substituted hex‐3‐ene‐1,5‐diynyl)benzonitriles ( 1 – 5 ) and their derivatives 7 – 23 were evaluated against several solid tumor cell lines and topoisomerase I. Compounds 1 – 5 show selective cytotoxicity with Hepa cells, and 2‐[6‐phenylhex‐3‐ene‐1,5‐diynyl]benzonitrile ( 5 ) reveals the most‐potent activity. Analogues 8 – 10 and 13 – 22 also have the same effect with DLD cells; 1‐[(Z)‐dec‐3‐ene‐1,5‐diynyl)‐4‐nitrobenzene 21 shows the highest activity among them. Moreover, 1‐[(Z)‐dec‐3‐ene‐1,5‐diynyl]‐2‐(trifluoromethyl)benzene ( 20 ) exhibits the strongest inhibitory activity with the Hela cell line. Derivatives 9, 10, 18 , and 23 display inhibitory activities with topoisomerase I at 87 μM . The cell‐cycle analysis of compound 5 , which induces a significant blockage in S phase, indicates that these novel enediynes probably undergo other biological pathways leading to the cytotoxicity, except the inhibitory activity toward topoisomerase I.     

Addition reaction of halogens to vinyl(pentafluorocyclopropanes): competition between a radical addition and an electrophilic addition

Vinylpentafluorocyclopropanes 1 react with I(2) to give the (Z)-1,5-adduct 2, whereas 1 reacts with Cl(2), Br(2) or I-Cl to produce (Z)-1,5-adduct 3 predominantly along with small amounts of 1,2-adduct 4, which are formed by a radical mechanism and an ionic mechanism, respectively.     

Gold(I)-catalyzed diastereo- and enantioselective 1,3-dipolar cycloaddition and Mannich reactions of azlactones

Azlactones participate in stereoselective reactions with electron-deficient alkenes and N-sulfonyl aldimines to give products of 1,3-dipolar cycloaddition and Mannich addition reactions, respectively. Both of these reactions proceed with good to excellent diastereo- and enantioselectivity using a single class of gold catalysts, namely C(2)-symmetric bis(phosphinegold(I) carboxylate) complexes. The development of the azlactone Mannich reaction to provide fully protected anti-α,β-diamino acid derivatives is described. 1,3-Dipolar cycloaddition reactions of several acyclic 1,2-disubstituted alkenes and the chemistry of the resultant cycloadducts are examined to probe the stereochemical course of this reaction. Reaction kinetics and tandem mass spectrometry studies of both the cycloaddition and Mannich reactions are reported. These studies support a mechanism in which the gold complexes catalyze addition reactions through nucleophile activation rather than the more typical activation of the electrophilic reaction component.     

A promising class of luminescent derivatives of Silver(I) and Gold(I)-N-heterocyclic carbene

Starting from proligand 1-methyl-2-(phenyl)imidazo[1,5-a]pyridine-2-iumchloride ( 1 .HCl), 1-methyl-2-(phenyl)imidazo[1,5-a]pyridine silver(I)chloride, ( 2 ) has been prepared. Synthesis, structures and photophysical properties of (2,2^/−bipyridyl)-1-methyl-2-(phenyl)imidazo[1,5-a]pyridinesilver(I)hexaflurophosphate, ( 3 ), 1-methyl-2-(phenyl)imidazo[1,5-a]pyridinesilver(I)carbazolate, ( 4 ) and 1-methyl-2-(phenyl)imidazo[1,5-a]pyridinegold(I)carbazolate, ( 5 ) are focused. Herein we have first reported the NHC-Ag-(bpy/carbazole). All the complexes have been characterized by elemental analysis, various spectroscopic studies and finally screened for luminescent properties. All the complexes are strongly emissive. Solid state structures of 2 , 3 , 4 and 5 have been determined by X-ray diffraction studies. Conventionally, complex 2 adopts linear geometry whereas complex 3 embraces triangular planar geometry around Ag; complex 4 and 5 clinches linear geometry around Ag/Au. All the complexes absorb light within 275–343 nm. Complex 3 is luminous at ~407 mn, whereas complex 4 and 5 luminous at ~360 nm having short life time 1.00–6.97 ns. The quantum yield (Φ_em) of the complexes varies 0.106–0.186. It is expected variation of luminescence arises due to change of metal and the chromophore (bpy/carbazole). Density Functional Theory (DFT) and Temparature Dependent Density Functional Theory (TDDFT) calculations were performed to verify crystallographically derived parameters and to calculate the UV–Vis properties of the ground state as well as of the first excited state of the complexes.     

Determination of water soluble imidazo-1,4-benzodiazepines in blood by electron- capture gas--liquid chromatography and in urine by differential pulse polaragraphy.

A sensitive and specific electron-capture gas--liquid chromatographic (GLC--ECD) assay was developed for the determination of 8-chloro-6-(2'-fluorophenyl)-1-methyl-4H-imidazo(1,5a)(1,4)benzodiazepine (I) or 8-chloro-1,4-dimethyl-6-(2'-fluorophenyl)-4H-imidazo (1,5a)(1,4)benzodiazepine (II) in blood. The assay for both compounds involves extraction into benzene--methylene chloride (9:1) from blood buffered to pH 12.6 The overall recovery of I and II from blood is 86% +- 5.0 (S.D.) and the sensitivity limit of detection is of the order of 2 to 3 ng of I or II per milliltre of blood. The major urinary metabolite of I is 8-chloro-6-(2'-fluorophenyl)-1-hydroxymethyl-4H-imidazo(1,5a)(1,4)benzodiazepine, (IA) present as a glucuronide conjugate while 8-chloro-6-(2'-fluorophenyl)-4-hydroxyl-1-methyl-4H-imidazo(1,5a)(1,4)benzodiazepine, (IB) and 8-chloro-6-(2'-fluorophenyl)-4-hydroxy-1-hydroxymethyl-4H-imidazo(1,5a)(1,4) benzodiazepine, (IC) are minor metabolites. The major metabolite IA is extracted into benzene--methylene chloride (9:1) from urine buffered to pH 11.0 (after incubation with glucuronidase--sulfatase as pH 5.0), and analyzed by differential pulse polarography (DPP) in 0.1 M phosphate buffer PH 3). The overall recovery of IA is 84 +- 3.0% (S.D.) with a sensitivity limit of 50 ng per millilitre of urine. The metabolites of compound II have not as yet been elucidated. The GLC--ECD and DPP assays were applied to the determination of blood levels and urinary excretion in dogs following single 10 mg/kg intravenous and oral doses of I and following single 6 mg/kg intravenous and 10 mg/kg oral doses of II. Blood levels of compound I were also evaluated in man following intravenous infusion of single 10 mg doses.     

Synthesis, Characterization and Crystal Structure of a Three-dimensional Coordination Polymer {[Cd(1,5-nds)(Him)2(H2O)]·2H2O}n

A novel cadmium(Ⅱ) coordination polymer {[Cd(1,5-nds)(Him)2(H2O)]·2H2O}n (1,5-nds = naphthalene-1,5-disulfonate and Him = imidazole) was synthesized based on the reaction of cadmium oxide and 1,5-naphthalenedisulfonic acid firstly, and then mixed with imidazole in methanol medium. Its structure was characterized by elemental analysis, IR and TGA, respectively. The crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to the triclinic system, space group P, with a = 8.5420(10), b = 10.2570(10), c = 13.361(2)(A), α = 100.704 (2), β = 100.195(2), γ = 108.873(3)°, C16H20Cd N4O9S2, Mr = 588.91, V = 1.0524(2) nm3, Dc = 1.858 g/cm3, Z = 2, F(000) = 592, μ= 1.294 mm-1, R = 0.0397 and wR = 0.1007 for 3180 observed reflections (I > 2σ(I)). Structural analysis shows that the cadmiun atom is coordinated with four oxygen atoms from three 1,5-nds and one water molecule together with two nitrogen atoms from two imidazoles, giving a distorted octahedral coordination geometry. The molecules are linked to form a two-dimensional coordination polymer based on bridging ligands of naphthalene-1,5-disulfonate anions, the sheets of which are then interacted via hydrogen bonds, leading to a three-dimensional network structure.     

Imidazo[1,5-a]pyridine: a versatile architecture for stable N-heterocyclic carbenes

The imidazo[1,5-a]pyridine skeleton provides a versatile platform for the generation of new types of stable N-heterocyclic carbenes. Rh(I) mono- (6) and biscarbenes (7) from imidazo[1,5-a]pyridin-3-ylidenes (ImPy) and derivatives such as 13 from a mesoionic carbene were synthesized and characterized.     

Catalytic isomerization of 1,5-enynes to bicyclo[3.1.0]hexenes

The cycloisomerization of 1,5-enynes catalyzed by cationic triphenylphosphinegold(I) complexes produces bicyclo[3.1.0]hexenes. Substitution at all positions of the 1,5-enyne is tolerated, leading to a wide range of bicyclo[3.1.0]hexane structures, including those containing quaternary carbons. Substrates containing a 1,2-disubstituted olefin undergo stereospecific cycloisomerization (cis-olefin produces cis-cyclopropane, and trans-olefin gives trans-cyclopropane). Additionally, enantioenriched bicyclo[3.1.0]hexenes can be obtained from the gold(I)-catalyzed cycloisomerization of enantioenriched 1,5-enynes with excellent chirality transfer. The preparation of tricyclic systems is accomplished through a gold(I)-catalyzed tandem cycloisomerization-ring enlargement reaction.     

A Coordination Polymer of Nickel(II) Based on a Pentadentate N, S, and O Donor Ligand

The synthesis, structural characterization, and electrochemical properties of a Ni(II) complex derived from the template reaction of N,N'-bis(2-mercaptoethyl)-1,5-diazacyclooctane nickel(II), Ni-1, with ICH(2)CO(2)Na are described. Blue N-(3-thiabutyl)-N'-(3-thiapentanoate)-1,5-diazacyclooctanenickel(II)iodide, [(tbtp-daco)Ni][I], [5]I, contains Ni(II) in an octahedral environment with N(2)S(2)O(2) donor atoms; one oxygen is from an adjacent [(tbtp-daco)Ni] ion and has the same distance to Ni(II) as the intramolecular oxygen, resulting in a coordination polymer. Complex [5]I.H(2)O, C(13)H(27)N(2)O(3)S(2)NiI, crystallizes in the orthorhombic space group Pbca with a = 10.898(3), b = 18.103(5), c = 19.020(5), and Z = 8. The extent to which the polymer is retained in solution is counterion dependent, which influences redox properties (accessibility of Ni(I) and Ni(III)).     

N‐Heterocyclic carbenes derived from imidazo‐[1,5‐a]pyridines related to natural products: synthesis,structure and potential biological activity of some corresponding gold(I) and silver(I) complexes

A series of Au(I) complexes ( 12 , 13 , 14 , 15 , 16 ) and Ag(I) complexes ( 17 , 18 , 19 , 20 ) derived from imidazo[1,5‐a]pyridin‐3‐ylidenes were synthesized from AuCl(SMe₂) or by reacting silver(I) acetate with 2,5‐dimethylimidazo[1,5‐a]pyridin‐2‐ium iodide or imidazo[1,5‐a]pyridin‐2‐ium salts, and were characterized using NMR spectroscopy, mass spectrometry and elemental analyses. In addition, the Au(I) complex 13 and the Ag(I) complex 19 were characterized using single‐crystal X‐ray diffraction. Using paclitaxel as a standard, all Au(I) and Ag(I) N‐heterocyclic carbene complexes were evaluated for their in vitro anti‐tumour activity against 12 cell lines using a monolayer cell survival and proliferation assay. The highest anticancer activity was found for complexes 15 , 13 and 14 with mean IC₅₀ values of 10.09, 10.42 and 12.28 μM, respectively. Copyright © 2016 John Wiley & Sons, Ltd.     

Thermolysis of the reaction products from 2-pyridylacetohydrazide and nitrous acid

2,3-Dihydroimidazo[1,5-α]pyridin-3-one (IV) was obtained by thermolysis of 2-pyridylacetyl azide (II) which was prepared from 2-pyridylacetohydrazide (I) on treatment with an equivalent mole of nitrous acid. Treatment of I with excess nitrous acid yielded α-oximino-α:-(2-pyridyl)-acetylazide (V). Thermal decomposition of V gave 3-(2-pyridyl)-1,2,4-4H-oxadiazolin-5-one (VII). 2-Cyanopyridine (IX) was obtained from V by the action of alkali. 2,3-Dihydroimidazo-[1,5-α ]pyridin-3-one (IV) was rearranged to VII upon treatment with nitrous acid. J. Chem. Soc., 14, 993 (1977)     

Mechanistic implications of an asymmetric intermediate in catalytic C-C coupling by a dinuclear nickel complex

An asymmetric nickel-nickel bonded intermediate was isolated in the reaction of biphenylene with bis(1,5-cyclooctadiene)nickel and i-Pr(3)P, where three of the four carbons are σ-bonded to one nickel. Mechanistic investigations support reactivity as a formal Ni(III)-Ni(I) complex; reductive elimination of cis-disposed Ni-C bonds from a single nickel centre directly provides a dinuclear Ni(I)-Ni(I) complex, a reaction relevant to dinuclear catalysis.     

Calorimetric investigation of the reaction of 1,5-cyclooctadiene with complexes of the type (acac)M(olefin)2 [M = Rh(I), Ir(I)]

The enthalpies of reaction of the complexes (acac)M(olefin)₂ (acac=acetyl-acetonate, M=Rh(I), Ir(I); olefin=ethylene, propene, vinyl chloride, vinyl acetate, methyl acrylate and styrene) with 1,5-cyclooctadiene in n-heptane, according to the reaction [(acac)M(olefin)₂ + 1,5COD → (acac)M(1,5COD) + 2 olefin]_n.heptane have been determined by solution calorimetry. From these results the influence of substituent R in the olefin CH₂CHR on the M---(CH₂CHR) displacement enthalpy has been derived. It is concluded that π back-bonding is slightly more important in the Ir---olefin bond than in the Rh---olefin bond. Furthermore, the data show that, as a result of steric factors which inhibit the approach of solvent molecules, solvation enthalpies are not additive.