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1.
《Analytical letters》2012,45(17-18):1393-1402
Abstract An open-tubular micro capillary column was prepared by coating the inner wall of a pyrex tube (50 μm i.d.) with polyamide. Chromatographic behaviors of trace amounts of various phenolic compounds, benzoic acid derivatives and aromatic amino and nitro compounds, were examined on this column. 相似文献
2.
《液相色谱法及相关技术杂志》2012,35(4):709-730
Abstract The optimization of enantiomeric resolution by mobile phase variation was studied with the chiral stationary phase derived from R-N-(3,5-dinitrobenzoyl) phenylglycine covalently coupled to 5 μm spherical 3-aminopropyl silica. Chromatography was routinely performed with mobile phase compositions having polarities as high as 2.5 without column deterioration. The relative strength of a solvent as a hydrogen acceptor was found to be an important basis for selection of the polar component in a binary mobile phase. The substitution of tert-butanol for 2-propanol or ethanol in an alcohol/hexane mixture, for example, afforded improved separation factors with several enantiomers. In addition, the need for a polar mobile phase such as 50/50 methylene chloride/hexane to minimize non-specific polar absorption of enantiomers has been demonstrated. Enhancement of specific chiral interactions and suppression of interfering reactions have been obtained with a number of clinically relevant derivatives as model compounds. 相似文献
3.
Donald R. Hogg Mohammad A.M. Rashid 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-2)
Abstract The coloured solutions of 2-nitrobenzenesulphenyl derivatives in 98% sulphuric acid have previously been suggested to contain either the conjugate acid of the sulphenyl derivative1 or the sulphenium ion in equilibrium with the starting material. 19F n.m.r. studies on solutions of 4-trifluoromethyl-2-nitrobenzenesulphenyl derivatives show that these compounds react in sulphuric acid to give the corresponding 2-amino- and 2-nitro-benzenesulphonic acids together with other products. 相似文献
4.
Maher A. EL-Hashash 《合成通讯》2019,49(16):2073-2085
New pyridine derivatives bearing p-dimethyl amino phenyl and p-bromophenyl moieties at position-4 and 6 have been prepared. The behavior of pyridone derivative 2 toward ethyl chloroacetate followed by hydrazine hydrate gave pyridinyl acetohydrazide derivative 7, and its behavior toward carbon electrophiles has been investigated by its reaction with aromatic aldehydes, ethyl acetoacetate, acetyl acetone, cyclohexanone, phthalic anhydride, maleic anhydride, and isatin affording the pyridine derivatives 8a–e to 16, respectively. Treatment of compound 2 with acrylonitrile in Et3N, yielded the N- alkylated derivative 17. Some pyrazole derivatives have been synthesized by interaction of the chalcone 1 with hydrazine hydrate afforded pyrazole derivative 18. Treatment of compound 18 with benzoyl chloride and or acetic anhydride resulted in the formation of the acylated compounds 19 and 20. Elemental and spectroscopic pieces of evidence characterized all the newly synthesized compounds. Some of the synthesized compounds were tested for their antibacterial activities against Gram-positive and Gram-negative bacteria. 相似文献
5.
Madalina Tudose Florin D. Badea Gabriela Ionita Maria Maganu Miron T. Caproiu Petre Ionita Titus Constantinescu Alexandru T. Balaban 《Structural chemistry》2010,21(6):1227-1234
Starting from 4-chloro-3,5-dinitrobenzoic acid 1, compounds 2–10 (N-alkoxy-3,5-dinitro-4-aminobenzoic acid esters where alkoxy stands for methoxy, carboxymethoxy, triphenylmethoxy, or corresponding
amides) have been obtained, from which compounds 3–5 and 7–10 are new, and for the known compounds 2 and 6 the synthetic procedure has been improved. The new derivatives have been characterized by appropriate means (IR, UV–Vis,
1H- and 13C-NMR, fluorescence) and their properties were studied. Thus, depending on their structure, the compounds have acid properties,
fluorescence and complexing properties with alkaline cations. 相似文献
6.
R. Gozalbes J. Gálvez R. García-Domenech F. Derouin 《SAR and QSAR in environmental research》2013,24(1):47-60
Abstract Molecular connectivity has been applied to the search of new compounds with activity against the protozoan Toxoplasma gondii, using a stepwise linear discriminant analysis (SLDA) which is able to classify a compound according its activity either as active or as inactive. Among the selected compounds, andrographolide and dibenzotiophene sulfone stand out, both with IC50 values lower than 1 μg/m1, which are comparable to these of drugs such as sulfamethoxazole, pyrimethamine and trimethoprim, with IC50 values equal to 1.1, 0.04 and 2.31 μg/ml, respectively. These results confirm the usefulness of our topological approach for the selection and design of new-lead drugs active against Toxoplasma gondii. 相似文献
7.
《液相色谱法及相关技术杂志》2012,35(10):1957-1966
Abstract A rapid method is described for the separation of the α-tocopherol model compound, 2,2,5,7,8-pentamethyl-6-chromanol (6), from 9 of its oxidation products in a single 35 minute run. Separated derivatives of 6, in order of elution, included the 5-cholesteroxymethyl (1), spirotrimer (2), spirodimer (3), 5-formyl (4), 5-ethoxymethyl (5), dihydroxydimer (7), chroman dione (8), quinone (9) and pyrano xanthene (10). A normal phase system, using gradient elution is employed, the eluent being monitored at 290 nm. The minimum detection limit for compounds 1–8 was 0.1 μg per injection and for compounds 9 and 10 it was 0.3 μg per injection. 相似文献
8.
Ali A. Abdel Hafez Ibrahim M. A. Awad 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3-4):381-389
Abstract Some new sulphonyl-N-heterocyclo-8-hydroxy quinolines have been synthesised by the reaction of 8-hydroxyquinoline-5-sulphonyl hydrazide with different active methylene compounds. The pyrazole, pyrazoline, pyrazolidine and pyridazine derivatives were reacted with some metal cations to give the corresponding chelates. All synthesized compounds have been screened in vitro for their biological activities. 相似文献
9.
Dobromir D. Enchev 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):273-284
Abstract The preparations of new cyclic derivatives of 1,2-alkadienephosphonic acids have been reported and the reactions of these compounds with bromine have been investigated. 相似文献
10.
Wan Sharifatun Handayani Wan Zullkiplee Ainaa Nadiah Abd Halim Maya Asyikin Mohd Ariff Hasnain Hussain 《Phosphorus, sulfur, and silicon and the related elements》2013,188(6):832-838
AbstractA series of symmetrical 1,3-bis thiourea 1a–e and 1,4-bis thiourea derivatives 2a–e have been successfully synthesized from the reactions of amines with 3-acetylbenzoyl isothiocyanate and 4-acetylbenzoyl isothiocyanate, respectively. All the synthesized compounds were characterized by FT-IR spectroscopy and 1H and 13C NMR spectroscopy. The compounds were screened for their antibacterial activity by turbidimetric method using gram-negative bacteria (E. coli ATCC 8739) using turbidimetric method. The newly synthesized bis-thiourea derivatives bearing aryl side chains showed good antibacterial activity against E. coli. The effect of the molecular structure of the synthesized compounds on the antibacterial activity is discussed. 相似文献
11.
Michael Pudovik Alexander Burilov Dmitry Cherepashkin Irina Nikolaeva 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4):561-564
Abstract The phosphorylation and silylation of α-mercaptocarbonyl compounds have been investigated. Novel different cyclic and linear silicon(phosphorus) containing derivatives have been obtained. 相似文献
12.
A. A. Prishchenko M. V. Livantsov I. F. Lutsenko 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4):231-234
Abstract Organophosphorus compounds containing a functional group in the a-position of the alkyl radical are of great interest in both theoretical fundamental investigations and for practical applications. Functionally substituted methyl-phosphonites and their derivatives, belonging to this broad class of organophosphorus compounds, are convenient objects for investigating mutual effects of trivalent phosphorus and a heteroatom, or functional groups attached to it in the a-position. They have also become key substances in obtaining new organophosphorus compounds. Functionally sub-stituted compounds of tetracoordinated phosphorus have been intensively investigated in recent years; rather convenient methods of synthesis of these compounds have been proposed and their properties have been studied in detail1. However, the corresponding compounds of tricoordinated phosphorus are not available or difficult to obtain. Recently we re-ported on the properties of halogen-substituted methylphos-phines and their derivatives2. The present paper is devoted to the synthesis and investigation of the reactivity of alkoxy-, dialkylamino- and carbonyl substituted methylphos-phonites and their derivatives. In synthesis of alkoxymeth-ylphosphonites and their analogs we were the first to use labile alkoxymethylmagnesium chlorides in the reactions with tricoordinated phosphorus acid chlorides3. Previously unknown dialkoxymethylphosphonites and their analogs were obtained from hypophosphorous acid and trialkylorthofor-mates. The process of esterification and dialkoxymethylat-ion of hypophosphorous acid, being dependent on a catalyst, proceeds in different ways and results in the formation of dialkoxymethylphosphonite structures 相似文献
13.
以2,4-二氯嘧啶为起始原料, 利用两个氯原子的活性差异, 经4-吡唑基-2-氯嘧啶合成了一系列4-吡唑基-2-芳氧基嘧啶类化合物, 通过1H NMR和元素分析对所合成的化合物进行了结构表征. 初步生物活性测定结果表明, 所合成的化合物都表现出一定的除草活性. 当嘧啶环2位的氯原子被芳氧基取代后, 化合物的除草活性均有不同程度的提高, 例如5c和4a相比, 100 μg•mL-1时化合物对油菜的抑制率由15.7%提高到85.4%, 对稗草的抑制率由原来的11.6%提高到84.0%. 相似文献
14.
Shilpi Jain Devendra Prakash Nagda G. L. Talesara 《Phosphorus, sulfur, and silicon and the related elements》2013,188(7):1665-1673
Some novel azaimidoxy compounds viz. 2-{[(4-chlorophenyl)diazenyl]oxy}-1H-isoindole-1,3-(2H)-dione (Va), and 1-{[1-naphthyldiazenyl]oxy}pyrrolidine-2,5-dione (IVc), etc. have been synthesized by a simple diazotization reaction followed by a coupling with 2-hydroxy-1H-isoindole-1,3(2H)-dione (III)/1-hydroxypyrrolidine-2,5-dione (II) of corresponding aromatic primary amine derivatives at a suitable pH. A similar reaction with a [1,3]thiazolo[4,5-b]pyridin-2-amine (VIII) lead us to some interesting results variable with a pH. The structure of all synthesized compounds has been established by IR, 1H NMR, and mass studies. These compounds have been screened for antimicrobial activities in order to evaluate the possibility of the derivatives to be used as potential chemotherapeutic agents. 相似文献
15.
E. Luboch A. A. Dvorkin Yu. A. Simonov 《Journal of inclusion phenomena and macrocyclic chemistry》1994,20(4):335-351
Lipophilic derivatives of benzo-12-crown-4 and naphtho-12-crown-4 have been synthesized. The behavior of the parent compounds and their derivatives in membrane ion-selective electrodes have been studied. Selectivity changes have been observed with the rise in lipophilicity. Crystal structures of the NaI and KI complexes of benzo-12-crown-4 (1 and2) have been determined by X-ray analysis. The alkali metal and iodide ions are in direct contact in2 but not in1. Compound1 [Na(benzo-12-crown-4)2]·I is triclinic, witha=13.368(8),b=10.727(7),c=10.325(4) Å; =73.56(4),=77.73(4), =108.70(5)°;Z=2, space group is
. Compound2 [K(benzo-12-crown-4)2·I] is monoclinic, witha=15.807(8),b=12.043(4),c=15.601(6) Å,=117.74(3)°;Z=4, space groupC2/c. In both compounds the cations interact with all oxygen atoms of two crown ether molecules. Correlation of the crystal structures and behavior of the crown ethers in ion-selective membrane electrodes is discussed.
Supplementary Data related to this article have been deposited with the British Library as Supplementary Publication No. 82185 (15 pages). 相似文献
16.
Marcus Vinícius Nora de Souza Maria Cristina Silva Lourenço Mônica Amado Peralta Raoni Schroeder Borges Gonçalves Thais Cristina Mendonça Nogueira Camilo Henrique da Silva Lima 《Phosphorus, sulfur, and silicon and the related elements》2013,188(12):2990-2997
The series of new N,N′-di(thiopheneacetyl)diamines derivatives, 8–17, were synthesized and evaluated for their in vitro antibacterial activity against Mycobacterium tuberculosis(TB), and the activity expressed as the minimum inhibitory concentration (MIC) in μ g/mL. Compound 13 was the only one determined to be active and exhibited a MIC 50 μg/mL, indicating that the alkyl chain-length of the diamines is critical for biological activity. This class of compound has not been evaluated before, and it could be a good starting point to find new lead compounds in the fight against multi-drug resistant TB. 相似文献
17.
New pyrazolo[1,5-a]quinazoline-3-carbonitriles 4a,b were obtained via cyclocondensation of 5-amino-3-cyanomethyl-1H-pyrazole-4-carbonitrile (1) with enaminones of 1,3-cyclohexanedione derivatives 2a,b in refluxing glacial acetic acid. Condensation of compounds 4a,b with various aromatic aldehydes furnished the corresponding arylidene derivatives 6a–j. On the other hand, condensation of 4a,b with o-hydroxybenzaldehydes yielded the polyheterocyclic compounds 10a–h. Coupling of compounds 4a,b with aryldiazonium chlorides led to formation of 2-arylhydrazono derivatives 12a–h. Also, reaction of compounds 4a,b with phenyl isothiocyanate, followed by addition of ethyl chloroacetate and chloroacetonitrile, afforded the polyheterocyclic compounds based on pyrazolo[1,5-a]quinazoline core. The reaction of compounds 4a,b with phenyl isothiocyanate and elemental sulfur gave the thiazole-2-thione derivatives 25a,b. The reaction of enamines of compounds 4a,b with each of hydrazine hydrate and guanidine hydrochloride afforded pyrazolo[4″,3″:5′,6′]pyrido[4′,3′:3,4]pyrazolo[1,5-a]quinazolin-8-ones 30a,b and pyrimido[5″,4″:5′,6′]pyrido[4′,3′:3,4]pyrazolo[1,5-a]quinazolin-9(10H)-ones 33a,b, respectively. The structures of all the newly synthesized compounds were elucidated by elemental analyses and spectral data. The plausible mechanisms have been postulated to account for their formation. 相似文献
18.
《Analytical letters》2012,45(12):1063-1074
Abstract Amino acid isothiocyanate derivatives have been used in GC/MS analysis. The best method providing these derivatives is decomposition of carboalkoxydithiocarbamates. Analysis by gas chromatography and mass spectrometry has shown that carbon oxysulfide, methanol, ethanol, amino acid ester isothiocyanate and trace carbon disulfide are pyrolysis products of amino acid ester carboalkoxydithiocarbamates. However, isothermal pyrolysis at 200° and direct MS analysis, FI and EI ionization modes, give rise to a few more by-products with m/z 145 and 177. This suggests a stepwise mechanism of thermal decomposition of the compounds studied. The number of by-products was seen to decrease when the R and R moieties were identical. 相似文献
19.
α, β-Unsaturated carbonyl compounds 2a, 2b, 3, and 4 were synthesized by the Knoevenagel condensation between 2-substituted quionoline-3-carboxaldehyde 1a and/or 1b with active methylene compounds. In addition, the synthesis of azlactone is achieved starting from 1a and N-acetylglycine. Synthesis of pyridine, pyrene, and pyrimidine derivatives 6–8 were accomplished via one-pot multicomponent reaction of 1b with acetyl acetone, malononitrile, and ammonium acetate; acetophenone, malononitrile, and NaOH; or acetyl acetone and urea in acidic medium. The new synthesized compounds showed good antimicrobial activities. The DFT calculations have been used to predict the electronic properties of the studied compounds. 相似文献
20.
AbstractIn this study, a new series of quinazoline and their annulated derivatives have been synthesized. A number of quiazolinone derivatives substituted at position-3 were prepared from 3, 1-benzoxazinone by the treatment of 3,1-benzoxazinone with different nitrogen nucleophiles such as, hydrazine hydrate, phenylhydrazine, ethanolamine, and cyano acetohydrazide afforded the quinazolinone derivatives 7–11. The reaction of hydrazide derivative 5 with aromatic aldehydes gave the Schiff’s bases derivative 16a–c. Some of the synthesized compounds were tested against the breast cancer cell line (MCF-7). The structures of all the newly synthesized compounds were established based on IR, 1H, 13C NMR, mass spectral data, and elemental analyses. 相似文献