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941.
Study of self-assembly of PNA TC8 monitored by UV thermal transition at 295 nm indicates formation of a C-C+ tetraplex (i-motif) in acidic pH, with higher stability than the analogous dTC8. 相似文献
942.
Deepak Singh Rathore Vimlesh Kumar Meena Chandra Pal Singh Chandel Krishna Swarup Gupta 《印度化学会志》2022,99(9):100631
The trace atmospheric volatile organic compounds(VOCs) are reported to influence the oxidation of dissolved sulfur dioxide, S(IV), by oxygen, which is an important reaction in atmospheric acid formation. In this work, the influence of 15 VOCs on uncatalyzed oxidation of S(IV) by oxygen has been investigated by following the disappearance of [O2]. The inhibition of oxidation reaction by toluene, aniline, benzene, cinnamic acid, hydroquinone, acrylamide, acrylonitrile and allyl alcohol was defined by the rate law(A):kVOC = k0/(1+B [Inh]) (A)where, kVOC, and k0 are the first order rate constants in the presence and the absence of VOCs respectively. B is the inhibition parameter and [Inh] is the concentration of inhibitor.On the other hand, fumaric, maleic and crotonic acids, which have conjugated CC bonds, catalyze the reaction defined by the rate law(B):kVOC = k0 + kcat [VOC] (B)where kcat is catalytic constant and [VOC] is the concentration of catalytic VOC.Interestingly, presence of 1-hexene, cyclohexene, methacrylic acid, methyl acrylate was without any significant effect on the rate of reaction. 相似文献
943.
J.F. Muller J.M. Magar D. Cagniant J.M. Mouchot J. Grimblot J.P. Bonnelle 《Journal of organometallic chemistry》1981,205(3):329-341
The complexes obtained by the action of vanadyl ethylate on some open-structured ligands (type 1,4,8,11-tetrathiaundecane TTU) are characterized by mass spectroscopy with laser impact (LAMMA) and by photoelectron spectroscopy ESCA. The results are compared with those obtained from some reference compounds and several fractions of asphaltenes. 相似文献
944.
Polysubstituted pyridines are prepared in good yield and with total regiocontrol by the one-pot reaction of an alkynone, 1,3-dicarbonyl compound and ammonium acetate in alcoholic solvents. This new three-component heteroannulation reaction proceeds under mild conditions in the absence of an additional acid catalyst and has been used in the synthesis of dimethyl sulfomycinamate, the acidic methanolysis degradation product of the sulfomycin family of thiopeptide antibiotics. 相似文献
945.
The thermal decomposition of arylidene tetrazolyl hydrazones has been studied under dynamic and isothermal conditions using a differential scanning calorimeter. Attempts have been made to evaluate the thermochemical and kinetic parameters of these compounds. It has been observed that the thermal stability of the tetrazole derivatives decreases with increasing substitution of nitro groups in the aromatic ring. 相似文献
946.
The synthesis of chiral diamines and diamino acids has been achieved from the corresponding N-arylsulfonyl aziridines through reaction with a chiral isocyanate and subsequent hydrolysis of 2-imidazolidinones. The method appears to be general and of wide applicability. 相似文献
947.
A synthesis of 6-aminonicotinic acid by electrochemical hydrogenation of 5-chloro-2-nitropyridine and electrochemical carboxylation of 2-amino-5-chloropyridine at a cathode surface in the presence of sulphuric acid and carbon dioxide in a dimethylformamide (DMF) solution at an apparent current density of 10 mA/cm2 using an undivided cell with good yields is reported. 相似文献
948.
Unambiguous synthesis of 2-methyl-3-isopropenylanisole () and 2-isopropenyl-3-methylanisole () has led to revision, from () to (), of the structure assigned to a monoterpene phenol ether isolated from . 相似文献
949.
Summary The compound disodium-1,8-dihydroxy-naphthalene-3,6-disulphonate (sodium salt of chromotropic acid) is employed as a colorimetric reagent for titanium. It is also known to produce coloured complexes with chromium(VI), vanadium and uranium. In the present paper the formation of colour with forty metallic ions has been studied qualitatively, in neutral as well as in alkaline and acidic media. It has been found that the reagent yields coloured complexes with mercury(I), tin(IV), platinum(IV), gold(III), tellurium(VI), molybdenum(VI), iron(III), aluminium(III), chromium(III), and uranyl(II) besides those recorded above.The colour reactions are particularly sensitive to uranyl(II), iron(III), mercury(I), tin(IV), gold(III) und molybdenum(VI). 相似文献
950.
A highly selective and efficient method for the unmasking of p-methoxybenzyl (PMB) ethers and esters has been developed by use of 20 mol % of zirconium(IV) chloride as Lewis acid in acetonitrile. The present method is very fast, and the conditions are tolerable to a variety of acid/base-sensitive protecting groups and substrates such as carbohydrates, terpenes, and amino acids. The products are obtained in good to high yields. 相似文献