共查询到20条相似文献,搜索用时 31 毫秒
1.
A. L. Shul’tsev 《Russian Journal of General Chemistry》2013,83(4):694-697
Reduction of 4-nitrostyrene with Fe0, Fe2+, and S2O 4 2? was studied. A new method of 4-aminostyrene synthesis was developed. 相似文献
2.
Yiyun Wang Ziyuan Li Yue Huang Changhua Tang Xiaoming Wu Jinyi Xu Hequan Yao 《Tetrahedron》2011,67(38):7406-7411
A mild copper(II)-catalyzed oxidation of 4-carboxythiazolines and 4-carboxyoxazolines to 4-carboxythiazoles and 4-carboxyoxazoles has been developed. Various substrates with alkyl or aryl substitutions at 2-position on azoline ring could be smoothly oxidized to the desired products in good to excellent yields. Moreover, the hydrolysis of the ester group could be avoided under this method. 相似文献
3.
A versatile and useful preparation of 4-pyridine carboxaldehyde, an important pharmaceutical intermediate, by vapour phase mode of oxidation of 4-pyridinemethanol over V-Mo-O catalyst is developed for the first time. The probable mechanism and experimental procedure are reported. 相似文献
4.
Marton J Glaenzel B Roessler J Golaszewski D Henriksen G 《Molecules (Basel, Switzerland)》2012,17(3):2823-2832
The route selection and development of a convenient synthesis of 4-carboxy-4-anilidopiperidines is described. Previous routes were hampered by the low yield of the target esters as well as the inability to convert the esters to the required free acids. Considerations for large-scale production led to a modified synthesis that utilised a tert-butyl ester of 4-carboxy-4-anilidopiperidines which resulted in a dramatic increase in the overall yield of the target N-propionylated- 4-anilidopiperidine-4-carboxylic acids and their corresponding methyl esters. These compounds are now available for use as precursors and reference standards, of particular value for the production of 11C and 18F-labelled 4-carboxy-4-anilidopiperidine radiotracers. 相似文献
5.
4-Methyl-4-(4-methoxyphenyl)-benzo[h]-4H-chromene is synthesised by condensation of 4-methoxyacetophenone and ethyl acetate in strong base, followed by coupling with 1-naphthol, reduction to the epimeric lactols and elimination of water. 相似文献
6.
4-Sulfenyl-2-carbamoyl-4-isoxazolin-3-ones (4) were designed on the basis of biological isosterism and prepared in four steps. Some of these compounds showed sufficient pre-emergent herbicidal activities against various kinds of weeds. Among the synthesized compounds, 2-(N-(4-chlorophenyl)-N-isopropylcarbamoyl)-4-ethylthio-5-methyl-4 -isoxazolin-3-one (4cd) exhibited the most promising activity. 相似文献
7.
J. L. Allen T. R. Jow J. Wolfenstine 《Journal of Solid State Electrochemistry》2008,12(7-8):1031-1033
The electrochemical phase transformation of carbon coated nanophase (60–70 nm) FePO4 to LiFePO4 was investigated by use of the Avrami–Johnson–Mehl–Eroofev equation. The analysis at three temperatures showed an Avrami exponent equal to one. Based upon reinterpretation and in agreement with recent microstructural evidence, a two-dimensional growth mechanism for the phase transformation is proposed in which the new phase grows in a direction perpendicular to the direction of lithium ion transport. Furthermore, the relatively low value of the activation energy for the phase transformation of 13 kJ/mol suggests that the phase transition is controlled by lithium ion diffusion along the phase boundary. 相似文献
8.
A facile and environment-benign oxidation by molecular oxygen was applied for the conversion of 4-carboxylate thiazolines to 4-carboxylate thiazoles. The substituent effect on thiazoline ring was investigated. It was found that electron-poor group on the thiazoline ring could facilitate the oxidation. 相似文献
9.
C3-Substituted-4-azaindoles were synthesized from pyridylacetonitriles in a two-step sequence allowing the easy introduction of a range of substituents. This strategy permits the rapid synthesis of 4-azamelatonin and a protected 4-azatryptophan. 相似文献
10.
A simple transformation of terpinen-4-ol (1) to dihydropinol (4) is described. S-Terpinen-4-ol was stereospecifically oxidized with vanadyl diacac to cis-terpinen-4-ol-epoxide (2). Reduction with LiAlD4 afforded the unexpected 1R-deutero-2S,4S-dihydroxy menthane (3) which was cyclized in acid to 4. 相似文献
11.
Lihua Bai Jianxia Guo Franklin A. Bontempo III Julie L. Eiseman 《Photochemistry and photobiology》2009,85(4):1011-1019
The ability to noninvasively measure photosensitizer concentration at target tissues will allow optimization of photodynamic therapy (PDT) and could improve outcome. In this study, we evaluated whether preirradiation tumor phthalocyanine 4 (Pc 4) concentrations, measured noninvasively by the optical pharmacokinetic system (OPS), correlated with tumor response to PDT. Mice bearing human breast cancer xenografts were treated with 2 mg kg−1 Pc 4 iv only, laser irradiation (150 J cm−2 ) only, Pc 4 followed by fractionated irradiation or Pc 4 followed by continuous irradiation. Laser irradiation treatment was initiated when the tumor to skin ratio of Pc 4 concentration reached a maximum of 2.1 at 48 h after administration. Pc 4 concentrations in tumor, as well as in Intralipid in vitro , decreased monoexponentially with laser fluence. Pc 4-PDT resulted in significant tumor regression, and tumor response was similar in the groups receiving either fractionated or continuous irradiation treatment after Pc 4. Tumor growth delay following Pc 4-PDT correlated with OPS-measured tumor Pc 4 concentrations at 24 h prior to PDT ( R 2 = 0.86). In excised tumors, OPS-measured Pc 4 concentrations were similar to the HPLC-measured concentrations. Thus, OPS measurements of photosensitizer concentrations can be used to assist in the scheduling of Pc 4-PDT. 相似文献
12.
A. A. Gevorkyan N. M. Khizantsyan P. I. Kazaryan G. A. Panosyan 《Chemistry of Heterocyclic Compounds》1981,17(2):113-115
It is shown that 4-methylenetetrahydropyran adds a methylene group under the conditions of the Simmons-Smith reaction to give 4,4-dimethylenetetrahydropyran. 4-Methyldihydro-2H-pyran and 4-methylenetetrahydropyran add dichlorocarbene in the presence of a catalyst, viz., triethylbenzylammonium chloride, to give two-ring adducts. It is shown that the adducts can be converted to ketals by refluxing for many hours with alcoholic alkali. The structures of the compounds obtained were established by gas-liquid chromatography and PMR and IR spectroscopy.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 167–169, February, 1981. 相似文献
13.
S. Wattanasin 《合成通讯》2013,43(16-17):1919-1925
A novel route to 4-aryl coumarins using the palladium-catalyzed coupling ofaryl stannanes with 4-trifluoromethanesulfonyloxy coumarin is described 相似文献
14.
Haraguchi K Takahashi H Shiina N Horii C Yoshimura Y Nishikawa A Sasakura E Nakamura KT Tanaka H 《The Journal of organic chemistry》2002,67(17):5919-5927
Three types of 4-thiofuranoid glycal with different 3,5-O-silyl protecting groups were prepared and their electrophilic glycosidation was investigated. The 3,5-bis-O-(tert-butyldimethylsilyl)-4-thiofuranoid glycal (5) was obtained through mesylation of 2-deoxy-4-thio-D-erythro-pentofuranose (4) and subsequent base-promoted elimination, while thermal elimination of sulfoxide derivatives was suitable for the preparation of 3,5-O-(tetraisopropyldisiloxane-1,3-diyl) (9) and 3,5-O-(di-tert-butylsilylene) (11) 4-thioglycals. The glycosidation reactions of these 4-thioglycals were carried out, in the presence of either PhSeCl or NIS, by using silylated derivatives of uracil, thymine, cytosine, and N(6)-benzoyladenine. Among the three 4-thioglycals, 11 was found to be an excellent glycosyl donor, forming the desired beta-anomer exclusively irrespective of the nucleobase employed. 相似文献
15.
Giovanni Appendino Giancarlo Cravotto Giovanni Palmisano Rita Annunziata 《合成通讯》2013,43(18):3359-3371
In the presence of one-electron metal oxidants (CAN, MAH), 4-hydroxycoumarin (1) adds to alkenes to give 2,3-dihydro-4H-furo[3,2-c][1]benzopyran-4-ones. 相似文献
16.
Zhai HJ Yang X Fu YJ Wang XB Wang LS 《Journal of the American Chemical Society》2004,126(27):8413-8420
Gaseous Fe(4)S(n)(-) (n = 4-6) clusters and synthetic analogue complexes, Fe(4)S(4)L(n)(-) (L = Cl, Br, I; n = 1-4), were produced by laser vaporization of a solid Fe/S target and electrospray from solution samples, respectively, and their electronic structures were probed by photoelectron spectroscopy. Low binding energy features derived from minority-spin Fe 3d electrons were clearly distinguished from S-derived bands. We showed that the electronic structure of the simplest Fe(4)S(4)(-) cubane cluster can be described by the two-layer spin-coupling model previously developed for the [4Fe] cubane analogues. The photoelectron data revealed that each extra S atom in Fe(4)S(5)(-) and Fe(4)S(6)(-) removes two minority-spin Fe 3d electrons from the [4Fe--4S] cubane core and each halogen ligand removes one Fe 3d electron from the cubane core in the Fe(4)S(4)L(n)(-) complexes, clearly revealing a behavior of sequential oxidation of the cubane over five formal oxidation states: [4Fe--4S](-) --> [4Fe--4S](0) --> [4Fe--4S](+) --> [4Fe-4S](2+) --> [4Fe-4S](3+). The current work shows the electron-storage capability of the [4Fe--4S] cubane, contributes to the understanding of its electronic structure, and further demonstrates the robustness of the cubane as a structural unit and electron-transfer center. 相似文献
17.
The high pressure phase diagrams of NH4ClO4 and NH4BF4 were studied by means of differential thermal analysis and volumetric techniques. The high temperature portions of these diagrams are intermediate between those of the corresponding potassium and rubidium salts, but at low temperatures the onset of hydrogen bonding causes the appearance of phases which are unique to the ammonium compounds. 相似文献
18.
19.
David Miller 《Journal of heterocyclic chemistry》1984,21(4):1025-1027
The rapid addition of methyl lithium to the 4-vinylpyridine system present in 4-{2,6-dihydroxy-4-(3-methyl-2-octyl)phenyl}-2-methyl-4-(4-pyridyl)but-3-en-2-ol ( 2 ) is reported. The α and β-4-{2,6-dihydroxy-4-(3-methyl-2-octyl)phenyl}-2,3-dimethyl-4-(4-pyridyl)butan-2-ols 4 and 5 formed, are cyclised by heating with 5N hydrochloric acid to trans and cis-3,4-dihydro-5-hydroxy-7-(3-methyl-2-octyl)-4-(4-pyridyl)-2,2,3-trimethyl-2H-1-benzopyran 6 and 7 respectively. 相似文献
20.
Liu J Kobayashi K Yang L Takisawa N Shirahama K 《Journal of colloid and interface science》1999,213(2):412-416
The binding of a photosurfactant, 4-butyl-azobenzene-4'-oxyethyltrimethyl ammonium bromide (BZTABr), to a linear polymer, sodium poly(2-acrylamide-2-methylpropane sulfonate) (PAMPS), has been studied by using a surfactant selective electrode. The photosurfactant undergoes a trans-cis transition on UV/vis irradiation. The binding behavior changes by varying the composition of the trans and cis forms in the solution. The ideal mixing-ideal cooperative binding model we had proposed previously for the binding of binary surfactants was applied to successfully predict the binding isotherms and the critical aggregation concentrations of the present systems. The binding of a trans-cis mixture of BZTABr to a polymer is analogous to the ideal mixed micelle formation. A sort of synergetic effect was found in the binding process. Copyright 1999 Academic Press. 相似文献