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71.
A new spectrofluorimetric method was developed for the determination of trace amounts of DNA using the calcein as a fluorescent probe. In the presence of appropriate amounts of the cationic surfactant cetyl trimethyl ammonium bromide (CTAB), the anionic dye calcein dimerizes. The weak fluorescence intensity of the dimer was enhanced by adding DNA at pH 6–7. The interaction between calcein–CTAB and DNA was studied on the basis of this behavior and a new method was developed for determining DNA. Under the optimal conditions, the enhanced fluorescence intensity was in proportion to the concentration of DNA in the range of 4.0 × 10−6 to 8.0 × 10−5 g L−1 for fsDNA and thermally denatured ctDNA (4.5 × 10−6 to 9.0 × 10−5 g L−1). The detection limits (S/N = 3) were 2.0 × 10−6 and 2.2 × 10−6 g L−1, respectively. This method was used for determining the concentration of DNA in synthetic samples with satisfactory results. 相似文献
72.
Dr. Nilofar Baral Soniya Rani Pinku Saikia Dr. Pradip Maity 《European journal of organic chemistry》2023,26(4):e202201238
Organophosphites are nucleophilic in nature and can act as a good leaving group owing to the stability of the phosphite anion. This dual reactivity makes them good candidates for nucleophilic organocatalysis. However, phosphites were introduced only in 2004 as the umpolung catalyst for acylsilane substrates utilizing sequential Brook rearrangements. Very recently, phosphites have been reported to catalyze aza-rearrangements and radical reactions. In this review, we discuss the reactivity parameters to understand its lack of use, as well as the potential for catalysis. 相似文献
73.
The use of solution 17O NMR spectroscopy in verifying the mechanism of trialkyl phosphite hydrolysis is presented. Trimethyl phosphite was reacted with 17O-labeled H2O at different temperatures and two reactant concentrations, with the reaction being monitored by 17O NMR. Kinetic details elucidated from the NMR spectra are also discussed. 相似文献
74.
含苯并噻唑杂环的α-氨基膦酸二苯酯的合成及生物活性 总被引:8,自引:0,他引:8
α氨基膦酸作为氨基酸的含磷类似物,具有广泛的除草[1]、杀菌[2]和植物生长调节活性[3].最近的研究表明,某些α氨基膦酸衍生物还具有较好的抗植物病毒活性[4,5].在研究植物病毒抑制剂的过程中,我们发现含苯并噻唑杂环的α氨基膦酸二乙酯类化合物... 相似文献
75.
1,3,4—噻二唑的α—氨基膦酸酯衍生物的合成及其生物活性 总被引:7,自引:4,他引:3
利用2-氨基-5-烷基-1,3,4-噻二唑、芳笛醛和亚磷酸三苯酯泊类Mannich反应,合成了一系列1,3,4-噻二唑的α-氨基膦酸酯生物。它们的结构级元素分析、IR,HNMR和MS这。初步生物活性测试结果表明,目标化合物对5种病人有一定的抑制作用。 相似文献
76.
A procedure was developed for the synthesis of tertiary phosphine oxides by alkylation of secondary phosphine oxides with
quaternary ammonium salts.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 390–392, February, 1999 相似文献
77.
78.
Two open‐framework bimetallic phosphites, [C6H18N2][Co0.3Zn2.7 (HPO3)4] ( 1 ) and [C2H8N]2[Co0.3Zn2.7(HPO3)4] ( 2 ) were synthesized and characterized. The inorganic frameworks of the two compounds are constructed from strictly alternating MO4 (M = Zn, Co)tetrahedra and HPO3 pseudo pyramids, forming three‐dimensional networks with 8‐ring and 12‐ring channels for 1 and 16‐ring channels for 2 . The anionic frameworks of the two compounds can be easily transformed to a neutral framework structure with 16‐ring channels at room temperature. 相似文献
79.
Roth M 《Journal of chromatography. A》2009,1216(10):1861-1880
Applications and prospects of two-phase, tuneable solvent systems composed of ionic liquids (ILs) and supercritical fluids with an emphasis on supercritical carbon dioxide (scCO(2)) are reviewed. The IL-scCO(2) biphasic systems have increasingly been used in diverse fields of chemistry and technology, and some examples of these applications are mentioned here. Rational design of such applications can obviously benefit from pertinent data on phase equilibria including the partition coefficients of the prospective products and reactants between the two phases. Therefore, a reliable technique to measure the limiting partition coefficients would be of value. Here, the pros and cons of supercritical fluid chromatography in this respect are discussed. An overview of methods for predictive thermodynamic modelling of binary (IL-scCO(2)) and ternary (solute-IL-scCO(2)) systems is also included. 相似文献
80.
Two three-dimensional open-framework zinc phosphites, H2aem·Zn3(HPO3)4·0.5H2O (1) and H2apm·Zn3(HPO3)4 (2), have been synthesized by a phosphorous acid flux method, where aem=4-(2-aminoethyl)morpholine and apm=4-(3-aminopropyl)morpholine. Compound 1 crystallizes in the monoclinic system, P21/c, a=9.5852(7) Å, b=20.3941(8) Å, c=10.5339(8) Å, β=94.125(9)°, V=2053.8(2) Å3, Z=4, R1=0.0319, wR2=0.0628. Compound 2 crystallizes in the monoclinic system, P21/n, a=8.589(2) Å, b=14.020(3) Å, c=16.606(3) Å, β=97.190(8)°, V=1983.9(7) Å3, Z=4, R1=0.0692, wR2=0.1479. Both compounds are based on (3,4)-connected networks with 8- and 12-ring channels, which are constructed from Zn3(HPO3)4 clusters as the same secondary building units. These inorganic clusters are spatially organized by different structure-directing agents into different three-dimensional frameworks. 相似文献