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1.
Oxidation of 1,3,5‐trisubstituted 4,5‐dihydro‐1H‐pyrazoles to the corresponding pyrazoles has been achieved by utilizing tetrabromine‐1,3,5,7‐tetrazatricyclo[3.3.1.13,7]decane complex, Br4‐TATCD, in glacial acetic acid under microwave irradiation and conventional thermal condition at room temperature with excellent yields. 相似文献
2.
Chiaki Kuroda Shigenobu Honda Yuki Nagura Hiroyuki Koshio Taku Shibue Tokio Takeshita 《Tetrahedron》2004,60(2):319-331
The two title carbon frameworks were synthesized utilizing a new type of iron-induced cyclization reaction of 2-(trimethylsilylmethyl)pentadienal. 2-Methylspiro[4.5]dec-2-en-1-one was obtained from (Z)- and (E)-4-cyclohexylidene-2-(trimethylsilylmethyl)but-2-enal. It was found that the (Z)-substrate isomerized to (E)-intermediate followed by cyclization to afford the initial product, 2-methylenespiro[4.5]dec-3-en-1-ol, which was isomerized to the above product. The cyclization of 4-(4-alkyl)cyclohexylidene-2-(trimethylsilylmethyl)but-2-enal proceeded stereoselectively. While, (E)-3-(cyclohex-1-en-1-yl)-2-(trimethylsilylmethyl)prop-2-en-1-al cyclized immediately affording 8-methylenebicyclo[4.3.0]non-9-en-7-ol. The corresponding (Z)-isomer gave several cyclization products as a complex mixture. 相似文献
3.
WANG Wen-Zhi FAN Neng-Ting 《结构化学》2002,21(6):634-636
<正>The title compound 4-(dichloroacetyl)-1-oxa-4-azaspiro[4. 5] decane (CAS number 71526-07-3, C10H15Cl2NO2, Mr= 252.13) was obtained by the reaction of dichloroacetic acid with 1-oxa-4-azaspiro[4. 5] decane. The crystal is of monoclinic, space group P21ln with the unit cell constants: a = 5.9619(4),b= 10.0066(8), c = 20.0986(4) A,β = 90.194(3)°, V= 1199(4) A3,Z = 4, Dc= 1.397 g/cm3, F(000) = 528, μ(MoKα) = 0.522 mm-1, R = 0.0611 and wR = 0.1656 for 1276 observed reflections (I > 2σ(I)). X-ray analysis reveals that the cyclohexyl adopts a chair conformation and the compound is a chiral one. 相似文献
4.
《The Journal of chemical thermodynamics》2006,38(3):240-244
Solubility of proline–leucine dipeptide, in water and in aqueous sodium chloride solutions, was measured at T = (288.15, 298.15, 308.15 and 313.15) K as a function of electrolyte concentration m = (0.1, 0.25, 0.5, 0.75 and 1) mol · kg−1 of water. Solubility data has been evaluated from density measurements using a vibrating tube densimeter. It has been observed that sodium chloride renders the dipeptide proline–leucine more soluble in water. Salting-in coefficients and standard free energies of transfer of proline–leucine, from water to aqueous sodium chloride solutions, have been calculated from the solubility data. Standard enthalpies and entropies of transfer have also been estimated and interpreted in terms of electrostatic and hydrophobic perturbed domains in the hydration shells of the dipeptide and of the cation and anion of the salt, as a function of temperature and salt concentration. 相似文献
5.
The experimental results reveal that solubility of cucurbit[n=5~8]urils is related with acidity of solution and metal ions. In hydrochloric acid, cucurbit[7]uril is the most soluble one, and cucurbit[8]uril is the least soluble one. There is no significant influence of alkaline metal ion on the solubility of cucurbiturils. The solubility of cu-curbit[7]uril increases greatly in a SrCl2 solution. However, increase of weight of cucurbit[n=5~8]urils suggest that cucurbit[n]urils can catch Ba2+ in a solution. 相似文献
6.
The solubility of gallic acid in (water + ethanol) binary solvents was determined from (293.15 to 318.15) K at atmospheric pressure using a thermostatted reactor and UV/vis spectrophotometer analysis. The effects of binary solvents composition and temperature on the solubility were discussed. It was found that gallic acid solubility in (water + ethanol) mixed solvents presents a maximum-solubility effect. Two empirical equations were proposed to correlate the solubility data. The calculated solubilities show good agreement with the experimental data within the studied temperature range. Using the experimentally measured solubilities, the thermodynamic properties of dissolution of the gallic acid such as Gibbs energy (ΔsolG°), molar enthalpy of dissolution (ΔsolH°), and molar entropy of dissolution (ΔsolS°) were calculated. 相似文献
7.
A facile copper(I)-catalyzed tandem reaction for the synthesis of 4,5-dihydropyrazolo[1,5-a]quinolines and pyrazolo[1,5-a]indoles is reported here. High efficiency and good yields are displayed in this transformation under mild reaction conditions. 相似文献
8.
《应用有机金属化学》2017,31(11)
Superparamagnetic nanoparticles of modified thioglycolic acid (γ‐Fe2O3@SiO2‐SCH2CO2H) represent a new, efficient and green catalyst for the one‐pot synthesis of novel spiro[benzo[a ]benzo[6,7]chromeno[2,3‐c ]phenazine] derivatives via domino Knoevenagel–Michael–cyclization reaction of 2‐hydroxynaphthalene‐1,4‐dione, benzene‐1,2‐diamines, ninhydrin and isatin. This novel magnetic organocatalyst was easily isolated from the reaction mixture by magnetic decantation using an external magnet and reused at least six times without significant loss in its activity. The catalyst was fully characterized using various techniques. This procedure was also applied successfully for the synthesis of benzo[a ]benzo[6,7]chromeno[2,3‐c ]phenazines. 相似文献
9.
Alaa A. Hassan Nasr K. Mohamed Lamiaa E. Abd El‐Haleem Stefan Bräse Martin Nieger 《中国化学》2016,34(8):814-822
A one step synthesis protocol for the conversion of heteroylthiosemicarbazides and 2,3‐dichloro‐1,4‐naphthoquinone to naphtho[2,3‐d]thiazoles, naphtho[2,3‐e][1,3,4]thiadiazines as well as bis(naphtho[2,3‐d]thiazolyl)copper(II) derivatives is described. The products were conclusively confirmed by single crystal X‐ray analyses. A mechanism for the formation of the products is presented. 相似文献
10.
The bis(calix [4] arene)3 was synthesized in moderate yield by the reaction of p-tert-butylcalix [4] arene (1) with 1,4-bis(chloromethyl) benzene (2). The conformation of all alkylated product 4 was investigated by the variable-temperature ^1H-NMR. 相似文献
11.
Delynn M. Hayes Issifu I. Harruna 《Journal of polymer science. Part A, Polymer chemistry》1998,36(2):277-281
Poly(benzobisoxazoles) (PBOs), poly(benzobisthiazoles) (PBTs) and copolymers thereof containing the 2,5-dihydroxybicyclo[2.2.2]octane moiety have been prepared and studied. The homopolymers were synthesized by the polycondensation of 2,5-dihydroxybicyclo[2.2.2]octane-1,4-dicarboxylic acid with 4,6-diamino-1,3-benzenediol dihydrochloride or 2,5-diamino-1,4-benzenedithiol dihydrochloride in poly(phosphoric acid). Random and block copolymers (PBO–PBT) were also prepared. The polymers were characterized by solubility, X-ray diffraction, spectroscopy (infrared and solid-state 13C nuclear magnetic resonance), and thermal analysis such as differential scanning calorimetry and thermogravimetric analysis. Thermogravimetric analysis showed thermal stability of the polymers above 375°C in air and under argon atmosphere. The polymers exhibited high resistance to organic and inorganic solvents. The polymers were converted to the more stable aromatic polymers via dehydration and retro Diels–Alder reactions of the 2,5-dihydroxybicyclo[2.2.2]octyl moiety by pyrolysis. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 277–281, 1998 相似文献
12.
A new class of [1,2,4]oxadiazolo[4,5‐a]thiazolo[2,3‐b]pyrimidin‐9(10H)‐one was prepared in moderate yields by the reaction of nitrile oxide with 2‐arylmethylidene‐6,7‐dihydro‐5H‐thiazolo[3,2‐a]pyrimidin‐3‐one. The reaction site of dipolarphile is the C?N of thiazolo[3,2‐a]pyrimidin‐3‐one rather than the expected C?C of arylmethylidene. The structures of the products were characterized thoroughly by IR, elemental analysis, MS, and NMR analysis. 相似文献
13.
A series of novel fused tetracyclic benzo[4,5]imidazo[1,2‐a]thiopyrano[3,4‐d]pyrimidin‐4(3H)‐one derivatives were synthesized via the reaction of aryl aldehyde, 2H‐thiopyran‐3,5(4H,6H)‐dione, and 1H‐benzo[d]imidazol‐2‐amine in glacial acetic acid. This protocol features mild reaction conditions, high yields and short reaction time. 相似文献
14.
Alkoxyamines containing two hydrophilic groups with great affinity to water are multipurpose compounds with important applications, either on theoretical or practical grounds. The thermodynamic characterization of aqueous mixtures of these compounds is scant. Ultrasound speed measurements have been made in 53 mixtures of the aqueous ethoxypropane-1-amine binary system, across the entire composition range and temperatures between T = (283.15 and 303.15) K, at atmospheric pressure. By combining ultrasound speed and density data, values of the isentropic compressibility were derived. Excess molar isentropic compressions were estimated and analytically fitted to Redlich–Kister polynomial equations. Excess partial molar quantities were then calculated including their limiting values, which were obtained from the Redlich–Kister fitting coefficients. The temperature dependences of limiting partial molar isentropic compressions and isobaric expansions were also scrutinized. Compressibility changes associated with different patterns of aggregation and hydration over the whole composition range are identified. 相似文献
15.
Resonant excitation energy transfer from [Cr(ox)3]3? to [Cr(bpy)3]3+ in the doped 3D oxalate networks [Rh1?xCrx(bpy)3][NaMIII1?yCry(ox)3]ClO4 (ox=C2O4?, bpy=2,2′‐bipyridine, M=Al, Rh) is due to two types of interaction, namely super exchange coupling and electric dipole–dipole interaction. The energy transfer probability for both mechanisms is proportional to the spectral overlap of the 2E→4A2 emission of the [Cr(ox)3]3? donor and the 4A2→2T1 absorption of the [Cr(bpy)3]3+ acceptor. The spin‐flip transitions of (pseudo‐)octahedral Cr3+ are known to shift to lower energy with increasing pressure. Because the shift rates of the two transitions in question differ, the spectral overlap between the donor emission and the acceptor absorption is a function of applied pressure. For [Rh1?xCrx(bpy)3][NaM1?yCry(ox)3]ClO4 the spectral overlap is thus substantially reduced on increasing pressure from 0 to 2.5 GPa. As a result, the energy transfer probability decreases with increasing pressure as evidenced by a decrease in the relative emission intensity from the [Cr(bpy)3]3+ acceptor. 相似文献
16.
L. Baklouti R. Abidi P. Thuery M. Nierlich Z. Asfari J. Vicens 《Journal of inclusion phenomena and macrocyclic chemistry》2001,40(4):323-325
The direct preparation of the sodium complex of 5,11,17,23-tetra(tert-butyl)-25,27-di(ethoxymethoxy)-26,28-(diethylacetamido) calix[4]arene 1.NaI is reported. The crystal structure of 1.NaI shows the calix unit to be in a cone conformation with the sodium located in the cavity delineated by the oxygen atoms. 相似文献
17.
基于四氮杂杯[2]芳烃[2]三嗪键合硅胶吸附剂(NC-Si),构建了固相萃取-高效液相色谱法同时测定河水中3种硝基苯酚和己烯雌酚的新方法。考察并获得了固相萃取和液相色谱分离的优化条件:将样品溶液pH调至5,以5 mL/min上样,经自制固相萃取柱净化,2 mL氨水-甲醇(2:98,v/v)洗脱;在C8柱上以甲醇-0.1%磷酸溶液为流动相进行梯度洗脱。4种目标分析物的检出限(LOD,S/N=3)为0.03~0.3 μg/L,定量限(LOQ,S/N=10)为0.1~1.0 μg/L;加标回收率为75.5%~104.2%,相对标准偏差(RSD,n=5)小于6.3%。该方法准确、可靠,可用于河水中硝基苯酚及己烯雌酚的灵敏检测。 相似文献
18.
Asha V. Chate Priyanka K. Bhadke Manisha A. Khande Jaiprakash N. Sangshetti Charansingh H. Gill 《中国化学快报》2017,28(7):1577-1582
An efficient and green method has been developed for the synthesis of 2H-indazolo[2,1-b]phthalazinetriones derivatives by employing 15 mol%β-cyclodextrinvia a one-pot multicomponent reaction of aldehyde,dimedone,hydrazine hydrate with succinic anhydride/phthalic anhydride in water at 80 ℃ for first time.The catalyst could be recovered and reused for four consecutive cycles without appreciable loss in catalytic activity and evaluated for in vitro antimicrobial activity against different Gram-positive and Gram-negative bacterial strains.The outcome of the screening study showed that compound 6d,6f and7 n exhibited excellent activity against E.coil.Whereas,compound 6f and 6h exhibited excellent activity against P.aeurginosa,and compound 6c,and 6e displayed again excellent activity against Staphylococcus aureus whereas compound 7o shows excellent activity against S.aureus and B.subtilis when compared with Ampicillin(standard control).The results indicated that maximum compounds are moderately effective against bacterial growth and their effectiveness is highest against standard drugs. 相似文献
19.
Hayedeh Bagheri Sadeghi Atefeh Tamaddon Hadi Afifinia Nasim Almasian Fatemeh Bozorgvar Somayeh Mollaei 《Electroanalysis》2011,23(10):2472-2478
A new chromium(III) PVC membrane sensor incorporating p‐tertiary‐butyl calix[4]arene as ionophore, potassium tetrakis as additive and dibutyl phthalate (DBP) as plasticizer was constructed. The electrode exhibited an excellent potentiometric response over a wide concentration range of 1.0×10?7–1.0×10?1 M with a Nernstian slope of 20±0.5 mV per decade. The detection limit was 5.0×10?8 M. The electrode showed a better performance over a pH range of 3.0–8.0, and had a short response time of about <15 s.The electrode was successfully applied to potentiometric titration of Cr (III) with EDTA and for direct determination of chromium(III) in waste water. 相似文献
20.
Li-Hwa Lu 《Journal of Molecular Structure》1999,460(1-3):1-9
The B3LYP/3-21G* ab initio molecular orbital method from the
program package was applied to study tricyclo[3,3,1,13,7]decane and tricyclo[3,3,1,13,7]decsilane molecules and their halogen derivatives (1,3,5,7-tetrahalotricyclo[3,3,1,13,7]decane and 1,3,5,7-tetrahalotricyclo[3,3,1,13,7]decsilane, C10H12X4 and Si10H12X4 respectively). The optimized structures of these compounds were obtained. Ionization potentials, HOMO and LUMO energies, energy gaps, heats of formation, atomization energies and vibration frequencies were calculated. The calculations indicate that these molecules are stable and have Td symmetry. Tricyclo[3,3,1,13,7]decsilane and its halogen derivatives (Si10H12X4) are found to have higher conductivity than tricyclo[3,3,1,13,7]decane and its halogen derivatives (C10H12X4). 1,3,5,7-Tetrafluorotricyclo[3,3,1,13,7]decane (C10H12F4) and 1,3,5,7-tetrafluorotricyclo[3,3,1,13,7]decsilane (Si10H12F4) were found to be the easiest compounds to form and the most difficult to dissociate of all 1,3,5,7-tetrahalotricyclo[3,3,1,13,7]decane and 1,3,5,7-tetrahalotricyclo[3,3,1,13,7]decsilane compounds, respectively. 相似文献