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排序方式: 共有108条查询结果,搜索用时 15 毫秒
41.
A novel and efficient ring expansion of benzothiazoles to functionalized 1,4-benzothiazines is described. The reactive 1:1 zwitterionic intermediates formed by addition of benzothiazoles to diaroylacetylenes were trapped with Meldrum’s acid under mild reaction conditions to produce 2-[2-hydroxy-2-aryl-2H-1,4-benzothiazin-3(4H)-yliden]-1-aryl-1-ethanones in excellent yields. 相似文献
42.
A multi-component synthesis of 3-aryl-1-(arylmethylideneamino)pyrrolidine-2,5-diones is described. A mixture of N-isocyaniminotriphenylphosphorane, an aldehyde, and Meldrum's acid undergo a 1:2:1 addition reaction under mild conditions to afford the title compounds in good to excellent yields. 相似文献
43.
Application of 8-amino-N-(2-hydroxybenzylidene)naphthyl amine as a neutral ionophore in the construction of a lanthanum ion-selective sensor 总被引:1,自引:0,他引:1
In this work, a novel La(III) membrane sensor based on 8-amino-N-(2-hydroxybenzylidene)naphthylamine (AIP) is presented. This electrode reveals good selectivity for La3+ over a wide variety of lanthanides metal ions. Theoretical calculations and conductance study of AIP to lanthanum and some other metal ions were carried out and confirmed selectivity toward La(III) ions. The electrode comprises 7% AIP, 30% PVC, 61% NPOE and 2% KTpClPB. The sensor displays a linear dynamic range between 1.0 × 10−7 and 1.0 × 10−1 M, with a nice Nernstian slope of 20.3 ± 0.3 mV per decade and a detection limit of 8.0 × 10−8 M. The potentiometric response is independent of pH in the range of 4.0-9.0. The proposed sensor posses the advantage of short response time, and especially, very good selectivity towards a large number of cations, such as Sm(III), Ce(III, Pr(III), Yb(III) and Hg(II), low detection limit and wide linear dynamic range in comparison with former ones. The electrode can be used for at least seven weeks without any considerable divergence in the potentials. It was used as an indicator electrode in the potentiometric titration of La(III) ions with EDTA. The sensor was applied to the determination of La(III) ions concentration in binary mixtures. It was also applied for the determination of fluoride ions in mouth wash preparations. 相似文献
44.
Microwave-assisted simple, one-pot, four-component synthesis of 2,4,6-triarylpyrimidines under solvent-free conditions 总被引:1,自引:0,他引:1
Mehdi Adib Niusha Mahmoodi Mohammad Mahdavi Hamid Reza Bijanzadeh 《Tetrahedron letters》2006,47(52):9365-9368
2,4,6-Triarylpyrimidines are synthesized via a simple, one-pot, four-component reaction between aryl methyl ketones, benzaldehydes, aromatic nitriles, and hydroxylamine under microwave irradiation and solvent-free conditions in good to excellent yields. 相似文献
45.
Reaction of Isonitriles with Dibenzoylacetylene Leading to Furan and Difuropyran Derivatives
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Mehdi Adib Shahzad Feizi Maryam Shahzad Shirazi Long‐Guan Zhu Hamid Reza Bijanzadeh 《Helvetica chimica acta》2014,97(4):524-531
A mixture of an isocyanide and dibenzoylacetylene in dry CH2Cl2 undergoes a smooth addition reaction at ambient temperature to furnish 3‐[5‐(alkylimino)‐3,4‐dibenzoyl‐2‐phenylfuran‐2(2H)‐yl]‐ 1‐phenylprop‐2‐yn‐1‐ones (1 : 2 adduct) and {2,5‐bis(alkylimino)‐4,7,8a‐triphenyl‐5H‐difuro[2,3‐b:3′,4′‐e]pyran‐3(8aH)‐yl}(phenyl)methanones (2 : 2 adduct). Single‐crystal X‐ray analyses conclusively confirmed the structures of the adducts. 相似文献
46.
Issa Yavari Mehdi Adib Fatemeh Jahani-Mogaddam Mohammad Hossain Sayahi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3):545-553
Crystalline phosphorus ylides are obtained in excellent yields from the addition reaction between triphenylphosphine, dimethyl acetylenedicarboxylate and strong NH-acids, such as 2-acetylpyrrole, indole, ethyl 3-indolylglyoxalate and N -benzyl-2-pyrrolylglyoxamate. Dynamic NMR effects are observed in the 1 H NMR spectra of stabilized ylides obtained from 2-acetylpyrrole and indole ( j G p = 67.1 and 68.8 kJmol m 1 respectively) and are attributed to restricted rotation around the carbon-carbon partial double bond resulting from conjugation of the ylide moiety with the adjacent carbonyl group. 相似文献
47.
Mehdi Adib Moharram Omidi Hamid Reza Bijanzadeh 《Phosphorus, sulfur, and silicon and the related elements》2013,188(8):1732-1738
Crystalline phosphorus ylides are obtained in nearly quantitative yields from the 1:1:1 addition reaction between triphenylphosphine, dialkyl acetylenedicarboxylates, and 4-aryl urazoles. 相似文献
48.
Research on Chemical Intermediates - The main goal of this study is to modify the polyethersulfone membrane by the grafting hyperbranched polyethylene glycol (HB-PEG) via a two-step grafting... 相似文献
49.
50.
An efficient 1-methylimidazole-catalyzed synthesis of dialkyl 2-[(4-methylphenyl)sulfonyl]-1H-pyrrole-3,4-dicarboxylates is described.The reactive 1:1 zwitterionic intermediate formed by the addition of 1-methylimidazole to dialkyl acetylenedicarboxylates is trapped by tosylmethyl isocyanide(TOSMIC) to afford the title compounds in excellent yields. 相似文献