An X‐ray crystallographic study of 2,2″,4,4′,4″,6,6′,6″‐octanitro‐1,1′ : 3′,1″‐terphenyl (ONT) has been carried out. The dihedral angles between benzene rings vary from 84.9° to 89.4°. Nonbinding interatomic distances of oxygen atoms inside all the nitro groups are shorter than the intermolecular contact radii for oxygen. On the basis of the DFT B3LYP/6‐31(d, p) method it was found that the difference between the X‐ray structure in the solid phase and DFT result for the gas phase is 98 kJ mol−1, and the bearer of the highest initiation reactivity of the ONT molecule in the solid phase should be the nitro group at 4″‐position, in contrast to those at 4′‐ or 6′‐position that play this role in the isolated molecule. It has been stated that the nitro groups at the reaction centers of the ONT molecule are relatively well specified by their 15N NMR chemical shifts. 相似文献
A variety of substituted 2,2′‐bipyridines were synthesized by a 1,2‐bis(diphenylphosphino)ethane (dppe)/cobalt chloride hexahydrate (CoCl2⋅6 H2O)/zinc‐catalyzed [2+2+2] cycloaddition reaction of diynes and nitriles, with all reactions exhibiting exclusive regioselectivity. Thus, symmetrical and unsymmetrical 1,6‐diynes and 2‐cyanopyridine reacted in the presence of 5 mol % of dppe, 5 mol % of CoCl2⋅6 H2O and 10 mol % of zinc powder to provide the corresponding 2,2′‐bipyridines. Under identical reaction conditions, 1‐(2‐pyridyl)‐1,6‐diynes and nitriles reacted smoothly with exclusive regioselectivity to produce 2,2′‐bipyridines in good yield. 2,2′‐Bipyridines were also obtained by the double [2+2+2] cycloaddition reaction of 1,6,8,13‐tetraynes with nitriles. Similarly, 2,2′:6′,2′′‐terpyridines were synthesized from 1‐(2‐pyridyl)‐1,6‐diyne and 2‐cyanopyridine. The regiochemistry observed can be explained by considering the electronic nature of cobaltacyclopentadiene intermediates and nitriles. A survey of the exclusive regiochemical trend gives reasonable credence to the synthetic potential of the present method. 相似文献
4-Nitroso-1-phenyl-3-methyl-5-aminopyrazole ( 1 ) was condensed with ethylcyanoacetate ( 2 ), malononitrile ( 4a ) and 2-cyanomethylbenzimidazole ( 4b ) to yield 6-hydroxy-5-cyano, 6-amino-5-cyano and 6-amino-5-(benzimidazol-2-yl)-3-methylpyrazolo [3,4-b]pyrazines 3, 5a and 5b , respectively. 5-Cyano-6-chloro derivative 6 obtained from 3 was converted to 3-aminopyrazolo[4′,3′:5,6]pyrazino[2,3-c]pyrazoles 8a and 8b by the treatment with hydrazin hydrate ( 7a ) and phenylhydrazine ( 7b ), respectively. Compound 5a was treated with formamide ( 9a ), urea ( 9b ) and thiourea ( 9c ) to give 4-aminopyrazolo[4′,3′:5,6]pyrazino[2′3′-d]pyrimidines 10a–10c. With refluxing acetic anhydride compounds 8a, 8b and 10a gave corresponding acetamido derivatives 8c, 8d and 10d. Compound 5a was treated with ethylorthoformate ( 11 ), acetic anhydride ( 12 ) or benzoylchloride ( 13 ) to give fused benzimidazopyrazolo[4′,3′:5,6]pyrazino[2′,3′-d]pyrimidines, viz., benzimidazol[1,2-c]pyrazolo[4,3-g]pteridines ( 14a–14c ). Some of the compounds 8, 10 and 14 were applied to polyester as disperse dyes and their fastness properties were studied. 相似文献
A novel asymmetric [4+2] annulation of vinyl ketones with oxindole‐derived α,β‐unsaturated imines has been developed in the presence of a multifunctional thiourea‐phosphine catalyst derived from a natural amino acid, providing the first phosphine‐catalyzed enantioselective synthesis of 2′,3′‐dihydro‐1′H‐spiro[indoline‐3,4′‐pyridin]‐2‐ones in good yields with excellent stereoselectivities under mild conditions.
Two novel Zn(II) coordination polymers, [Zn5(pytpy)8(fum)4(H2O)4(OH)2]n · n(CH3OH) · 2n(H2O) (1) and [Zn3(pytpy)4 (btc)2]n · 2n(H2O) (2) (pytpy = 4′-(4-pyridyl)-3,2′:6′,3″-terpyridine, H2fum = fumaric acid, H3btc = 1,3,5-benzenetricarboxylic acid) have been hydrothermally synthesized and structurally characterized. Complex 1 is a 2D layer structure, which is constructed from linear pentanuclear Zn(II) subunits interconnected via bidentate-bridging pytpy ligands and tridentate-bridging fum2− anions. Complex 2 is a 3D network structure, μ2-pytpy ligands link the layers based on the heart-like hexanuclear subunits to form the 3D network. Both complexes show strong fluorescence emission upon excitation at 310 nm in solid state. Additionally, these two complexes possess great thermal stabilities, especially for 2, the framework is stable up to 350 °C. 相似文献
Li2O‐ stabilized β″‐alumina was synthesized by the double zeta process. The effect of Sm2O3 additive as the sintering aid, on microstructure, mechanical and electrical properties of Li2O‐ stabilized β″‐alumina ceramics was studied by means of X‐ray diffraction, field emission scanning electron microscope, biaxial flexure test and ionic conductivity measurement. The results indicated that both the fracture strength and the ionic conductivity of the sample containing 0.2 wt% Sm2O3 improved approximately 52% and 54%, respectively, that can be attributed to its higher density, higher amount of β″‐Al2O3 phase and more uniform microstructure. 相似文献
3,3′‐Bisazidomethyl oxetane‐3‐azidomethyl‐3′‐methyl oxetane (BAMO‐AMMO) tri‐block copolymer was successfully synthesized by azidation of a polymeric substrate containing bromo leaving groups, and an alternative block energetic thermoplastic elastomer (ETPE) was prepared by chain extension reaction. The tri‐block copolymer was characterized by Fourier transform infrared (FTIR), 1H NMR, and 13C NMR spectroscopy, X‐ray diffraction (XRD), and thermogravimetric analysis (TGA). It was found that the composition of the copolymer is nearly 1 : 1; crystallinity of the copolymer (71.81 %) is less than that of PBAMO (78.30 %). This is due to a partly mixture between soft and hard segments. Kinetic result shows that a crosslinking network is formed after the decomposition of azide group. Tensile strength of alternative block ETPE is 150 % of traditionally synthesized BAMO‐AMMO ETPE. 相似文献
The synthesis and characterization of three new bis(2,2′:6′,2′-terpyridine) (tpy) ligands containing different hydrazone spacers between the metal-binding domains are described. Treatment of 1,4-benzenedicarbaldehyde bis(2,2′:6′,2′′-terpyridin-4′-ylhydrazone) (1) with [(tpy)RuCl3] in the presence of N-ethylmorpholine results in the formation of [(tpy)Ru(μ-1)Ru(tpy)]4+. Single crystal X-ray diffraction data for [(tpy)Ru(μ-1)Ru(tpy)][PF6]4·8MeCN confirm the ability of the hydrazone-based ligand to bridge two ruthenium(II) centres, providing proof-of-principle for the application of this class of flexible ligand in the design of coordination polymers. 相似文献
The solid state structure of [Ru(Phtpy)2][PF6]2 · 4MeCN has been determined (Phtpy = 4′-phenyl-2,2′:6′,2″-terpyridine); [Ru(Phtpy)2]2+ cations pack into sheets by virtue of {M(tpy)2}2 embraces, and the MeCN solvent molecules are involved in NH–C interactions which prevent the efficient packing of adjacent sheets. Comparisons with related structures lead to some generalizations about packing motifs in salts containing [M(Phtpy)2]2+ or [M(pytpy)2]2+ cations (pytpy = 4′-pyridyl-2,2′:6′,2″-terpyridine). 相似文献
An efficient and convenient method was developed for the one‐pot construction of the complex polycyclic heterocycles pyrrolo[1,2‐a:2′,1′‐c]‐/pyrido[2,1‐c]pyrrolo[1,2‐a]quinoxalinones from two simple starting materials via a gold(I)‐catalyzed domino reaction. This strategy presents an atom economical and environmentally friendly transformation, in which two new C N bonds and one new C C bond are formed in a one‐pot reaction process. 相似文献
Li2O‐stabilized β″‐alumina powder has been synthesized by the solid‐state and double‐zeta processes. It was shown that by the double‐zeta process, the β″‐alumina fraction of sintered samples was 10% higher, showing around 99% of β″‐alumina fraction. Using β″‐alumina powder produced by the double‐zeta process, the sintered density improved, microstructure was more uniform and leads to improvement in hardness, strength and Weibull modulus due to more uniform microstructure and absence of abnormal grain growth. The higher fracture toughness of the solid‐state‐processed samples could be due to crack deflection mechanism. 相似文献
2′‐Fluoro‐2′‐deoxyguanosine has been reported to have potent anti‐influenza virus activity in vitro and in vivo. Herein we describe the synthesis and biological evaluation of 6‐modified 2′‐fluoro‐2′‐deoxyguanosine analogues and their corresponding phosphoramidate ProTides as potential anti‐influenza virus agents. Whereas the parent nucleosides were devoid of antiviral activity in two different cellular assays, the 5′‐O‐naphthyl(methoxy‐L ‐alaninyl) ProTide derivatives of 6‐O‐methyl‐2′‐fluoro‐2′‐deoxyguanosine, 6‐O‐ethyl‐2′‐fluoro‐2′‐deoxyguanosine, and 2′‐deoxy‐2′‐fluoro‐6‐chloroguanosine, and the 5′‐O‐naphthyl(ethoxy‐L ‐alaninyl) ProTide of 6‐O‐ethyl‐2′‐fluoro‐2′‐deoxyguanosine displayed antiviral EC99 values of ~12 μM . The antiviral results are supported by metabolism studies. Rapid conversion into the L ‐alaninyl metabolite and then 6‐modified 2′‐fluoro‐2′‐deoxyguanosine 5′‐monophosphate was observed in enzymatic assays with yeast carboxypeptidase Y or crude cell lysate. Evidence for efficient removal of the 6‐substituent on the guanine part was provided by enzymatic studies with adenosine deaminase, and by molecular modeling of the nucleoside 5′‐monophosphates in the catalytic site of a model of ADAL1, thus indicating the utility of the double prodrug concept. 相似文献