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1.
Wenling Li Tao Dong Peilan Chen Xiaolin Liu Meijie Liu Xiaoqian Han 《Tetrahedron》2017,73(21):3056-3065
The simple synthesis of (±)-parthenostilbenins A and B and (±)-quadrangularins A and B, as well as several unnatural resveratrol dimers, was successfully accomplished for the first time. Moreover, (±)-restrytisols B, (±)-leachianols F and G were efficiently prepared with higher yields compared with those in the literatures. The regioselective oxidative coupling reactions of 3,5-dibromo-resveratrol catalyzed by different enzymes in various solvent systems were used as key steps. The coupling mechanisms for the formation of distinct dimeric skeletons were also proposed. 相似文献
2.
Guohua Wei 《Tetrahedron letters》2008,49(38):5488-5491
A convenient method has been developed for regioselective anomeric deacylation of carbohydrate derivatives using FeCl3·6H2O in CH3CN. Operational simplicity, economic consideration, high yield, and low toxicity are key features associated with this protocol. 相似文献
3.
J.S. Yadav B.V. Subba Reddy Ch. Suresh Reddy A.D. Krishna 《Tetrahedron letters》2007,48(11):2029-2032
3-Alkylindoles undergo smooth oxidation with IBX in the presence of CeCl3·7H2O in aqueous acetonitrile at ambient temperature to afford the corresponding 3-hydroxyoxindoles in high yields. This method is very useful for the direct preparation of 3-hydroxyoxindoles from 3-alkylindoles. Operational simplicity, mild and neutral reaction conditions in aqueous solution are the key features of this protocol. 相似文献
4.
An inexpensive and readily available catalyst, Zn(OAc)2·2H2O is successfully evaluated for effective one-pot synthesis of propargylamines with moderate to excellent yields for most of the substrates screened, without the need of base, co-catalyst or additive in the presence of air. 相似文献
5.
An efficient procedure for the synthesis of substituted indenes through the FeCl3·6H2O-catalyzed intramolecular Friedel-Crafts cyclization of aryl-substituted allylic alcohols has been developed. This method features the easily available starting materials, cheap catalyst, simple manipulation, and mild conditions. 相似文献
6.
d-Glycals readily undergo cyclization with aryl amines in the presence of CeCl3·7H2O-NaI under mild and neutral conditions to afford a novel sugar derived tetrahydroquinoline derivatives in good yields with high stereoselectivity. The stereochemistry of the products was assigned by using various NMR studies. 相似文献
7.
利用精密自动绝热热量计测定了Nd(Gly)2Cl3·3H2O在80-357K和Pr(Ala)3Cl3·3H2O在80-374K温区的热容. 根据两个化合物的热容计算出了相对于参考温度298.15K的热力学函数(HT?H298.15)和(ST?S298.15). 根据热重(TG)分析结果, 提出了这两个稀土化合物可能的热分解机理. 利用溶解-反应恒温热量计测定相关化合物的溶解焓并设计盖斯热化学循环, 计算出了两个化合物的标准摩尔生成焓. 相似文献
8.
FeCl3·6H2O-promoted skeleton-rearrangement of 1-substituted-3-benzazepines was further exploited. Both 1-aryl- and 1-alkyl- or 1-alkenyl-benzazepines underwent this reaction smoothly. The rearrangement products were used to prepare a series of novel derivatives containing both tetrahydroisoquinoline (THIQ) and tetrahydropyrimidin-4(1H)-one scaffolds through a Mannich-type process. 相似文献
9.
The synthesis and crystal structure of Ni2P2O6·12H2O are reported. The compound was synthesized from aqueous solutions of nickel chloride and sodium hypodiphosphate at room temperature. The space group is orthorhombic, Pnnm. Unit cell dimensions are , , and , Z=4. The product is unstable with respect to dehydration above room temperature. 相似文献
10.
A new magnesium borate MgO·3B2O3·3.5H2O has been synthesized by the method of phase transformation of double salt and characterized by XRD, IR and Raman spectroscopy as well as by TG. The structural formula of this compound was Mg[B6O9(OH)2]·2.5H2O. The enthalpy of solution of MgO·3B2O3·3.5H2O in approximately 1 mol dm−3 HCl was determined. With the incorporation of the standard molar enthalpies of formation of MgO(s), H3BO3(s), and H2O(l), the standard molar enthalpy of formation of −(5595.02±4.85) kJ mol−1 of MgO·3B2O33.5H2O was obtained. Thermodynamic properties of this compound was also calculated by group contribution method. 相似文献
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12.
Crystalline tungsten oxide hydrate (WO3·1/3H2O) nanorods have been prepared by a hydrothermal process using Na2WO4·2H2O and 4-phenylbutylamine as a structure-directing agent. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and thermal analysis techniques have been used to characterize the structure, morphology and composition of the nanorods. The WO3·1/3H2O nanorods are up to several hundred nanometers in length, and the widths and thicknesses are 40 and 8 nm, respectively. A study of the electric properties in the temperature range 170–730 °C and frequency range 5–13 MHz is reported. The obtained results show that the activation energies are about 0.07, 0.63 and 2.46 eV for o-WO3·1/3H2O, h-WO3 and m-WO3, respectively. The as-synthesized materials are promising for chemical and energy-related applications such as catalysts and electrochemical devices, and may be applied in rechargeable lithium-ion batteries. 相似文献
13.
A very simple procedure for the efficient oxidation of thiols to disulfides catalyzed by I2/CeCl3·7H2O in graphite and ethyl acetate as the solvent, in an open system at room temperature is described. The reaction proceeds cleanly under mild conditions and was performed with aromatic, aliphatic, and heterocyclic thiols. 相似文献
14.
Filip SvonsonBojan Šoptrajanov Ljupco PejovViktor Stefov 《Vibrational Spectroscopy》2011,55(2):188-194
The Fourier transform infrared spectra of Cs2CaCl4·2H2O as well as those of a series of its partially deuterated analogues were recorded at room and at liquid-nitrogen temperature (RT and LNT, respectively). The RT Raman spectra of the protiated form and of its almost completely deuterated analogue were also studied. The combined results from the analysis of the spectra were used to assign the observed bands. The mechanical anharmonicity of the OH(D) stretching and bending motions were further analyzed by computing the corresponding anharmonicity constants by several algorithms. The obtained trends in the series of structurally similar compounds were discussed. 相似文献
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16.
Magnus G. Johnston 《Journal of solid state chemistry》2004,177(11):4316-4324
Three new hydrated scandium selenites have been hydrothermally synthesized as single crystals and structurally and physically characterized. Sc2(SeO3)3·H2O crystallizes as a new structure type containing novel ScO7 pentagonal bipyramidal and ScO6+1 capped octahedral coordination polyhedra. Sc2(SeO3)3·3H2O contains typical ScO6 octahedra and is isostructural with its M2(SeO3)3·3H2O (M=Al, Cr, Fe, Ga) congeners. CsSc3(SeO3)4(HSeO3)2·2H2O contains near-regular ScO6 octahedra and has essentially the same structure as its indium-containing analogue. All three phases contain the expected pyramidal [SeO3]2- selenite groups. Crystal data: Sc2(SeO3)3·3H2O, Mr=524.85, trigonal, R3c (No. 161), , , , Z=6, R(F)=0.018, wR(F2)=0.036; Sc2(SeO3)3·H2O, Mr=488.82, orthorhombic, P212121 (No. 19), , , , , Z=4, R(F)=0.051, wR(F2)=0.086; CsSc3(SeO3)4(HSeO3)2·2H2O, Mr=1067.60, orthorhombic, Pnma (No. 62), , , , , Z=4, R(F)=0.035, wR(F2)=0.070. 相似文献
17.
Two new layered gallophosphates Co(en)3·Ga3P4O16·5H2O (1) and trans-Co(dien)2·Ga3P4O16·3H2O (2) have been hydrothermally synthesized using the racemic mixture of chiral metal complex Co(en)3Cl3 and Co(dien)2Cl3 as the structure-directing agent, respectively. Their structures are determined by single-crystal X-ray diffraction analysis and further characterized by X-ray power diffraction, ICP, elemental, and TG analyses. The structures of 1 and 2 consist of vertex-linking GaO4 and PO3(=O) tetrahedral units forming macroanionic [Ga3P4O16]3− sheets with a 4.6-net. The 4.6-net is characteristic of chiral [3.3.3] propellane-like structural motifs. The sheets of 1 stack in an ABAB sequence, with a pair of enantiomers of chiral Co(en)33+ cations residing in the interlayer region. The sheets of 2 array in a helical fashion with an ABCDEF stacking sequence, with only one enantiomer of chiral Co(dien)23+ cations residing in the interlayer region. Structural elucidation of 1 and 2 reveals that there exist stereo-specific correspondence between the metal complex template and the structure of the inorganic host. Crystal data: 1, Co(en)3·Ga3P4O16·5H2O, orthorhombic, Pnna (No. 52), a=8.6618(2) Å, b=21.6071(5) Å, c=13.7426(4) Å, Z=4, R1=0.0337 (I>2σ(I)), wR2=0.0985 (all data); 2, Co(dien)2·Ga3P4O16·3H2O, hexagonal, P6522 (No. 179), a=8.5152(7) Å, b=8.5152(7) Å, c=63.278(8) Å, R1=0.1183 (I>2σ(I)), wR2=0.2864 (all data) and Z=6. 相似文献
18.
Tungsten oxide hydrate (WO3·H2O) nanoplates and flower-like assemblies were successfully synthesized via a simple aqueous method. The effects of reaction parameters in solution on the preparation were studied. Nanoplates and nanoflowers can be selectively prepared by changing the amount of H2C2O4. In-situ assembly of nanoplates to nanoflowers was also proposed for the formation of assembled nanostructures. In addition, the reaction time and temperature have important effects on the sizes of the as-obtained samples. Crystal structure, morphology, and composition of final nanostructures were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Optical properties of the synthesized samples and the growth mechanism were studied by UV-vis detection. Degradation experiments of Rhodamine B (RhB) were also performed on samples of nanoplates and nanoflowers under visible light illumination. Nanoflower sample exhibited preferable photocatalytic property to nanoplate sample. 相似文献
19.
We describe here the first example in which glycerol has been transformed into chlorohydrin esters using an ionic liquid and hydrated aluminium chloride. The method avoids using Crown-18 ether, which was needed to obtain a similar yield when KCl was used. Alkyl and aryl acids can be used, although yields are very dependent on the carboxylic acid used. 相似文献
20.
Saikat Das Sharma 《Tetrahedron letters》2008,49(14):2216-2220
InCl3·3H2O was found to be a mild and effective catalyst for the efficient, one-pot, three component synthesis of 2,4,5-trisubstituted imidazoles at room temperature. Moreover, the utility of this protocol was further explored conveniently for the one-pot, four component synthesis of 1,2,4,5-tetrasubstituted imidazoles in high yields. 相似文献