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1.
Synthesis and Antimicrobial Activities of Novel 2‐[substituted‐1H‐pyrazol‐4‐yl] Benzothiazoles,Benzoxazoles, and Benzimidazoles 下载免费PDF全文
Vikas S. Padalkar Bhushan N. Borse Vinod D. Gupta Kiran R. Phatangare Vikas S. Patil Nagaian Sekar 《Journal of heterocyclic chemistry》2016,53(5):1347-1355
In an endeavor to find a new class of antimicrobial agents, a series of novel substituted benzimidazole, benzoxazole, and benzothiazole derivatives 6 containing pyrazole moiety have been synthesized by reaction of 3‐aryl‐4‐formyl pyrazole 4 with substituted phenylenediamine or o‐aminophenol or o‐aminothiophenol 5 . Reaction of phenyl hydrazine or 2‐hydrazinopyridine 1 with substituted acetophenones 2 gave the corresponding hydrazones 3 , which on Vilsmeier–Haack reaction with POCl3–DMF gave substituted 3‐aryl‐4‐formyl pyrazoles 4 . All final compounds 6a , 6b , 6c , 6d , 6e , 6f , 6g , 6h , 6i , 6j , 6k were evaluated for in vitro antibacterial activities against Escherichia coli and Staphylococcus aureus strains and in vitro antifungal activity against Candida albicans and Aspergillus niger strains by using serial dilution method. The antimicrobial activities were expressed as the minimum inhibitory concentration in µg/mL. The compound containing benzimidazole and benzoxazole moiety gave better antibacterial and antifungal activities than benzothiazole compounds. 相似文献
2.
G. Turan-Zitouni Ü. Uçucu A. Özdemir P. Chevallet Y. Tunali 《Phosphorus, sulfur, and silicon and the related elements》2013,188(11):2183-2188
Some 2-[(benzazole-2-yl)thio]diphenylmethylacetamide[3pc] derivatives were synthesized by reacting 2-chloroacethylaminodiphenylmethane with benzazole-2-thions. The structure elucidation of the compounds was performed by IR, 1 H NMR, and MS-FAB spectral data. Antimicrobial activity of the compounds was examined. Some of the compounds have shown similar antifungal activities against C. albicans when compared with ketoconazole. It was also observed that some of these compounds have moderate antimicrobial activity when compared with chloramphenicole. 相似文献
3.
《Green Chemistry Letters and Reviews》2013,6(2):139-145
Abstract An efficient and mild protocol has been developed for the preparation of benzimidazoles, benzoxazoles, and benzothiazoles from reactions of aldehydes with o-substituted aminoaromatics in the presence of catalytic amount of Indion 190 resin. Short reaction time, ambient conditions, simple work-up procedure, high yield, easy availability, reusability, and use of an eco-friendly catalyst are some of the striking features of the present protocol. 相似文献
4.
Yu. A. Moskvichev N. P. Gerasimova A. N. Pashinin P. V. Korikov N. A. Nozhnin E. M. Alov O. S. Kozlova 《Chemistry of Heterocyclic Compounds》2001,37(9):1162-1167
The reaction of nitriles and of methyl imino ester hydrochlorides of arylsulfonyl(thio)propionic acids with o-phenylenediamine, o-aminophenol, and o-aminothiophenol has been studied. A series of new 2-substituted benzazoles has been synthesized containing arylsulfonyl(thio)propionic acid fragments. 相似文献
5.
Zakaria Benzekri Houda Serrar Sara Sibous Ali Ouasri Ali Rhandour 《Green Chemistry Letters and Reviews》2016,9(4):223-228
An easy synthetic protocol for the synthesis of biologically active benzimidazole, benzothiazole and benzoxazole derivatives has been demonstrated using a hybrid crystal NH3(CH2)4NH3SiF6 as a mild and efficient heterogeneous catalyst. Short reaction times, solvent-free conditions, good to excellent yields, easy reusability and use of an eco-friendly catalyst are some of the significant attributes of the present method. 相似文献
6.
Oxidation of phenylhydrazine and 1,2-disubstituted hydrazines with dichlorocarbene afforded the corresponding diazenes and hydrazones with the intermediate formation of the unstable azomethine imines, which were determined by their cycloaddition to dimethyl malcate.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1489–1492, June, 1996. 相似文献
7.
Reaction of 2, 3-dihydro-1H-1. 5-benzodiazepines with dichlorocarbene generated in situ using benzyltriethylammonium chloride (TEBA) as a phase transfer catalyst in chloroform-aqueous sodium hydroxide mixture gave mainly 1,2-cycloadducts, cis and trans-1a, 3-disubstituted-1, 1-dichloro-1a, 2,3,4-tetrahydro-1H-azirino[1,2-a][1,5]benzodiazepines (2.3), and formylated 1,2-cycloadducts, trans-1a,3-disubstituted-1, 1-dichloro-4-formyl-1a, 2, 3, 4–1 H-azirino[1, 2-a][1, 5]benzodiacepines (4). The stereo-structures of cycloadducts and the mechanism are also discussed. 相似文献
8.
Solvent‐free organic reactions were studied over periodic mesoporous silica (SBA‐15) containing a Cu(II) organometallic complex. This heterogeneous catalyst was achieved by coordination of Cu(II) ions with the diaminosarcophagine ligand and then its grafting onto the surface of SBA‐15. This catalyst displayed ordered mesoporous channels, which implies an extremely high dispersion of the Cu(II) complex and the convenient diffusion of reactant molecules into the pore channels. Therefore, this catalyst can offer high activity and also facile separation or recycling when compared with its homogeneous counterparts. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
9.
Pinggui Yi Hongliang Peng Zhaoxu Wang Xianyong Yu Xiaofang Li Yonghong Liang 《中国化学》2011,29(4):650-654
The ground‐ and excited‐state intramolecular proton transfer processes of 2‐(2‐R (R?OH, NH2, SH) phenyl (or pyridyl)) benzoxazoles (or benzothiazoles) are investigated by the DFT methods. The calculated results indicate that in the ground state there is a high correlation (R=0.9950) between the proton transfer barrier and the intramolecular hydrogen bonds (IMHB) strength. The increase of the strength of IMHB in the proton transfer processes leads to a larger barrier contributions. Intramolecular proton transfer process pathway is along with the minimal difference of change value in the IMHB angle. In the excited‐state, there is a similar relationship between the IMHB and the barrier. 相似文献
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11.
Ramanjulu Abinaya Selvaraj Elavarasan B. Binish Dr. K. Mani Rahulan Prof. Dr. Kalpattu K. Balasubramanian Dr. Kamaraj Manokaran Dr. Elumalai Varathan Dr. Baburaj Baskar 《European journal of organic chemistry》2023,26(4):e202201098
Herein we report a simple and efficient oxidative coupling of various aryl methyl amines with diverse coupling partners, such as o-phenylenediamine (benzene-1,2-diamine), 2-aminobenzenethiol and 2-aminobenzamide, to synthesize the corresponding heterocycles using scalable and reusable heterogeneous catalysts under visible light irradiation. A systematic investigation led to the synthesis of benzimidazoles, benzothiazoles and quinazolinones under air atmosphere in very good to excellent yields. The strategy is atom economical and found to be tolerance towards different functional groups, and wide range of substrate scope. Furthermore, the methodology was demonstrated for its suitability on scale up and reusability. The density functional theory (DFT) calculations and the analysis of band structures of pristine and Ba doped CoMoO4 systems showed that the doping of Ba in place of Co improved the catalytic performance of the system. 相似文献
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K. V. Turov T. K. Vinogradova V. S. Brovarets B. S. Drach 《Russian Journal of General Chemistry》2010,80(4):825-828
The accessible two-center electrophilic substrate 4-tosyl-2-phenyl-5-chloro-1,3-thiazole reacts regioselectively with N-, O-, and S-nucleophiles to eliminate a chloride ion. The analog of this substrate, 4-tosyl-2-phenyl-5-p-chlorophenylsulphonyl-1,3-thiazole, reacts with “soft” and “hard” nucleophiles differently: with the participation of C5 or C4 center, respectively, that seems to be caused by the principle of “symbiosis” in the transition state. 相似文献
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Rifaat Hilal Ahmed A. Abdel Khalek Shabaan A. K. Elroby 《International journal of quantum chemistry》2005,103(3):332-343
The ground‐state equilibrium geometries of benzothiazole, benzoxazole, and benzimidazole were optimized at the density functional theory (DFT)/6‐31G** level of theory. Proton affinities on each of the possible sites in the studied series of compounds have been calculated at the DFT/6‐31G**/6‐311++G** level. The results indicate clearly that N‐site protonation is strongly favored over X‐site protonation (X = NH, O, S) for the series studied. Correlation of the computed proton affinities to the energy (EHOMO) of the highest occupied MO in the gas phase and in solution has been explored and discussed. A comprehensive investigation of the effect of solvent on the process of protonation of the studied compounds has been performed. Different dielectric continuum models (i.e., Onsager, PCM, and IPCM) have been tested; their performance and range of applicability are reported and discussed. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2005 相似文献
16.
Maryam Zakeri Majid Moghadam Valiollah Mirkhani Shahram Tangestaninejad Iraj Mohammadpoor‐Baltork Zari Pahlevanneshan 《应用有机金属化学》2018,32(1)
In this paper, the design and characterization of a new heterogeneous catalyst by incorporation of copper ions into the nanosilica modified by thiole–based dendrimer are reported. The prepared catalyst was characterized by FT–IR, TGA, elemental analysis, FE–SEM, TEM, XPS and ICP–OES techniques. This material was used as catalyst in the synthesis benzimidazoles and benzothiazoles by the reaction of substituted benzaldehydes with 1,2–diaminobenzene or 2–aminothiophenol, respectively. The advantages of the present catalytic system are high yields, mild conditions and short reaction times. On the other hand, this new synthesized catalyst was recycled very well and reused several times without significant loss of its catalytic activity. 相似文献
17.
N. G. Komissarova N. G. Belenkova O. V. Shitikova L. V. Spirikhin M. S. Yunusov 《Russian Chemical Bulletin》2005,54(11):2659-2663
The addition of dichlorocarbene generated under phase transfer catalysis conditions to the double bond of betulonic acid occurs
stereoselectively and is accompanied by transformation of the carboxy group leading to the dichloromethyl ester and chloride
of 3-oxo-20,29-(dichloromethano)lupan-28-oic acid. Together these products, the chloride of the starting betulonic acid is
formed depending on the reaction conditions. The reaction of dichlorocarbene with methyl betulonate leads to the corresponding
cyclopropane adduct in a quantitative yield.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2574–2578, November, 2005. 相似文献
18.
In this article, a study on reactions of tertiary allylic amines and dichlorocarbenes had been described. Tertiary allylic amines could result from an interesting de-N-allylation/formylation reaction under the treatment of dichlorocarbenes. Notably, amines containing steric substituents or electron-deficient aromatic substituents on the nitrogen will go through cyclopropanations of the carbon–carbon double bond. 相似文献
19.
Denis LeGourrirec Vladimir A. Kharlanov Robert G. Brown Wolfgang Rettig 《Journal of photochemistry and photobiology. A, Chemistry》2000,130(2-3):101-111
The azoles 2-(2′-hydroxyphenyl)oxazole (HPO) and 2-(2′-hydroxyphenyl)-4-methylthiazole (HPT) have been synthesised and studied in order to compare their photophysical characteristics. Their absorption and emission properties are reported in non-polar, alcoholic and aqueous media. Ground and excited state pK data were determined by spectroscopy and a model is proposed to explain the behaviour of HPT and HPO as a function of the pH. Excitation spectra and quantum chemical calculations suggest an equilibrium of ground state conformers. The calculations also predict a small energy barrier for rotation in the first excited singlet state for the proton transferred tautomers. The resulting twisted structure of the tautomer form possesses a biradicaloid nature, and is near-degenerate in energy with the first excited triplet state. 相似文献
20.
A highly yielding and fast method for the synthesis of heterocyclic compounds with trialkyl orthoformate using molecular sieve 3Å as a catalyst is described. 相似文献