共查询到19条相似文献,搜索用时 296 毫秒
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N. I. Baram F. G. Kamaev Kh. L. Ziyaev L. Biktimirov A. I. Ismailov G. B. Nazarov B. T. Ibragimov 《Chemistry of Natural Compounds》1988,24(5):550-553
A number of new Schiff's bases of gossypol with aromatic amines and sulfanilamide compounds has been obtained. It has been shown by UV and PMR spectroscopy and x-ray structural analysis that in some solvents they exist predominantly in the quinoid form. For dianilinegossypol (in the solid state) the quinoid structure has been demonstrated and two polymorphic modifications have been revealed by x-ray structural analysis.A. S. Sadykov Institute of Bioorganic Chemistry, Uzbek SSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 650–654, September–October, 1988. 相似文献
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Andrew Kuttler Sravanthi Durganala Albert Fratini Alexander B. Morgan Vladimir Benin 《Heteroatom Chemistry》2013,24(5):361-371
The present report describes the X‐ray structural and theoretical studies of some new pinacolboronate esters, and it also outlines the use of the target structures in Suzuki coupling reactions to produce new aromatic or heteroaromatic esters and amides. X‐ray structural analysis of the studied compounds revealed that the pinacolborane ring's position with respect to the benzene ring varies, depending on the particular environment. An ortho‐positioned carboxylic ester (methyl ester) causes a nearly perpendicular orientation of the pinacolborane unit with respect to the benzene ring, whereas an ortho‐positioned amide (N,N‐dimethylamide) causes the pinacolborane unit to orient itself nearly coplanar. A plausible explanation has been provided, based on both steric and electronic factors. 相似文献
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Synthesis of New Functionally Substituted 1-R-tetrazoles and Their 5-Amino Derivatives 总被引:2,自引:0,他引:2
S. V. Voitekhovich A. N. Vorob'ev P. N. Gaponik O. A. Ivashkevich 《Chemistry of Heterocyclic Compounds》2005,41(8):999-1004
It has been shown that amino derivatives of sulfanilamide, and also some functionally substituted primary arylamines and cycloalkylamines,
undergo heterocyclization with triethyl orthoformate and sodium azide with the formation of 1-monosubstituted tetrazoles.
Primary amines of the azole series, 5-aminotetrazole, 5-amino-1-methyltetrazole, 4-amino-1,2,4-triazole, and also less basic
arylamines (4-fluoro-3-nitroaniline, 2,6-dibromo-4-nitroaniline) did not react. An efficient method of introducing an amino
group into position C(5) of the tetrazole ring of 1-aryltetrazoles is proposed, based on alkaline decomposition of the tetrazole ring and heterocyclization
of the resulting N-arylcyanamides on interaction with ammonium azide generated in situ.
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Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1174–1179, August, 2005. 相似文献
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Ana Tačić Ivan Savić Vesna Nikolić Ivana Savić Snežana Ilić-Stojanović Dušica Ilić Slobodan Petrović Mirjana Popsavin Agnes Kapor 《Journal of inclusion phenomena and macrocyclic chemistry》2014,80(1-2):113-124
Sulfanilamide belongs to the group of drugs that have a bacteriostatic effect on different pathogenic microorganisms. This activity originates from the competitive antagonism with p-aminobenzoic acid, which is an integral part of folic acid. The safe use of sulfanilamide is limited due to poor solubility in the aqueous medium. Therefore, the aim of this paper is the synthesis of sulfanilamide, as well as preparing and structural characterization of its inclusion complexes with cyclodextrins. The crude sulfanilamide was obtained in the synthesis between acetanilide and chlorosulfonic acid according to the standard procedure. The synthesized sulfanilamide was recrystallized from water in order to obtain the satisfactory purity of the substance. Sufanilamide was complexed with β-cyclodextrin and 2-hydroxypropyl-β-cyclodextrin by the co-precipitation method. A molecular encapsulation of sulfanilamide was confirmed by using FTIR, 1H-NMR, XRD and DSC methods. Phase-solubility techniques were used to assess the formation of the inclusion complex between sulfanilamide and cyclodextrins. The photostability of sulfanilamide and its inclusion complexes was estimated by UVB irradiation in a photochemical reactor by applying the UV–Vis method. Based on the UV–Vis analysis, sulfanilamide:2-hydroxypropyl-β-cyclodextrin complex was presented as more photostable than sulfanilamide:β-cyclodextrin complex and sulfanilamide. The obtained results enable the potential use of these inclusion complexes for the preparation of oral formulations due to the enhanced solubility of sulfanilamide. 相似文献
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为寻找具有杀菌活性的三唑类先导化合物,采用活性亚结构拼接方法,将香豆素环和硫醚结构单元引入到三唑类化合物分子中,合成一系列未见文献报道的新型含香豆素环和硫醚结构的三唑类衍生物。经~1H NMR、~(13)C NMR、IR、MS和元素分析对所合成化合物的结构进行了表征。初步生物活性测试表明,部分目标化合物在试验浓度下具有一定的抑菌活性。 相似文献
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Birandra K. Sinha Julia T. Arnold Colin F. Chignell 《Photochemistry and photobiology》1982,35(3):413-418
Abstract— Ultraviolet light (A > 295 nm) induced binding of sulfanilamide to cellular macromoleculcs has been examined. It was found that the drug bound irreversibly to native DNA, and complexes containing one drug molecule per 80 nucleotides were obtained after 60 min of irradiation under anaerobic conditions. Oxygen reduced this binding significantly. More drug was bound to RNA and heat denatured DNA under identical conditions. The binding of sulfanilamide to DNA was found to induce nicking of circular closed plasmid DNA and cross-linking of calf thymus DNA. Oxygen significantly decreased nicking and cross-linking of DNA. Irradiation of sulfanilamide and human serum albumin resulted in covalent binding of the drug to the protein and a concomitant increase in protein crosslink-ing. While oxygen decreased covalent binding, crosslinking increased under aerobic conditions. These reactions may be important in the photosensitization caused by sulfanilamide. 相似文献
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López-Sánchez M Ruedas-Rama MJ Ruiz-Medina A Molina-Díaz A Ayora-Cañada MJ 《Talanta》2008,74(5):1603-1607
A procedure for rapid quantitative analysis of pharmaceutical powders is described. Powdered samples were measured in a rotating cell in order to avoid sub-sampling problems by increasing the irradiated area. Quantitative determination of sulfathiazole and sulfanilamide, using a simple univariate calibration model is proposed. Even though both antibacterials are of the same chemical family (sulfonamides), the richness of structural information contained in the Raman spectra allowed their determination using the area of two selected bands (1255 and 1629 cm−1 for sulfathiazole and sulfanilamide, respectively). Relative standard deviation (R.S.D.) values (n = 10) of 3.35% and 3.46% for sulfathiazole and sulfanilamide, respectively, demonstrate the good reproducibility of the measurement technique with the rotating cell. The method was successfully applied to the analysis of synthetic mixtures and commercial pharmaceutical powders. The procedure is suitable to be applied to pharmacopoeial uniformity of content testing of batches. 相似文献
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Anand VG Pushpan SK Venkatraman S Narayanan SJ Dey A Chandrashekar TK Roy R Joshi BS Deepa S Sastry GN 《The Journal of organic chemistry》2002,67(18):6309-6319
The syntheses of new aromatic 30pi heptaphyrins either through a [5 + 2] or a [4 + 3] acid-catalyzed condensation and oxidative coupling reactions of easily available and air-stable precursors are reported. The methodology followed is not only simple and efficient but also allows synthesis of a range of heptaphyrins with different heteroatoms in the core. The oxidative coupling reactions of modified tripyrranes 11 and tetrapyrranes 12 were found to be dependent on the acid concentration used and as well as the substituents present on the meso position. The change of meso aryl substituents in 11 and 12 to meso mesityl substituents gave a new heptaphyrin 18. The structural characterization has been done with extensive 1H and 2D NMR studies. The heptaphyrins reported here show rich structural diversity when the connections of the heterocyclic rings are altered, and accordingly, one ring and two ring inversions have been observed. By a judicious choice of the precursors it has been possible to control the site of ring inversion either in the bithiophene unit or in the tripyrrane unit. Theoretical calculations performed on three different heptaphyrins, 4, 5, and 17, also reveal that the inverted structures are approximately 35-40 kJ lower in energy relative to the corresponding noninverted structures. Furthermore, one of the heptaphyrins 10c shows the presence of two conformers in solution in the ratio 1:2 and no interconversion between the conformers have been observed in the temperature range of 343-228 K. On protonation, the aromaticity and the ring inversions are retained and the deltadelta values vary in the range 10.07-20.59 ppm. The energies of the Soret maxima and the HOMO-LUMO gap vary linearly with the increase in pi electrons further justifying the aromatic nature of the heptaphyrins. 相似文献
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A new spectrophotometric method for the assay of very small amounts of chloramine-T has been developed using sulfanilamide. This method is simple and accurate within the limits described. 相似文献