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61.
The development of new strategies for synthesis of six-membered O-heterocycles has remained a highly attractive but challenging proposition. An overview of the application of microwave irradiation in oxygen-containing six-membered heterocyclic compounds synthesis is presented, focusing on the developments in the past 5–10 years. This contribution covers the literature concerning the total synthesis of six membered O-heterocycles. 相似文献
62.
Solid-phase organic synthesis is a rapidly expanding area of synthetic chemistry that is being widely exploited in the search for new medicinally important compounds using combinatorial techniques. In recent decades, a large number of reports related to solid-phase synthesis of heterocycles have appeared because of the wide variety of their biological activity. In this review, we report the important role of solid-phase synthesis in the synthesis of nitrogen containing six-membered ring heterocycles. 相似文献
63.
G.B. Dharma RaoM.P. Kaushik 《Tetrahedron letters》2011,52(39):5104-5106
A simple and efficient trans-acetoacylation method for the synthesis of β-keto ester derivatives has been described using ytterbium(III) triflate as a new catalyst under solvent-free condition. This method was found to be efficient and convenient for the synthesis of a wide variety of β-keto ester derivatives. 相似文献
64.
65.
Kumar KS Kumar PM Kumar KA Sreenivasulu M Jafar AA Rambabu D Krishna GR Reddy CM Kapavarapu R Shivakumar K Priya KK Parsa KV Pal M 《Chemical communications (Cambridge, England)》2011,47(17):5010-5012
Concurrent construction of five and six membered fused N-heretocyclic ring was achieved via a conceptually new three-component reaction affording 6,6a-dihydroisoindolo[2,1-a]quinazoline-5,11-diones as novel inhibitors of TNF-αin vitro. This represents one of the few examples of direct TNF-α inhibition by small molecules. 相似文献
66.
The natural abundance carbon-13 nuclear magnetic resonance spectra of some methaqualone metabolites were recorded using the pulse fourier transform technique. The chemical shift of various carbon resonances have been assigned on the basis of the chemical shift theory, multiplicities observed in SFORD spectrum and comparison with the chemical shifts of the corresponding carbons of methaqualone. 相似文献
67.
68.
Summary The problem of the construction of an equilibrium surface taking the surface tension into account leads to Laplace-Young equation which is a nonlinear elliptic free-boundary problem. In contrast to Orr et al. where an iterative technique is used for direct solution of the equation for problems with simple geometry, we propose here an alternative approach based on shape optimization techniques. The shape of the domain of the liquid is varied to attain the optimality condition. Using optimal control theory to derive expressions for the gradient, a numerical scheme is proposed and simple model problems are solved to validate the scheme. 相似文献
69.
Kishore Kumar Anantoju Thirumala Chary Maringanti Baquer Syed Mohd. 《Tetrahedron letters》2018,59(30):2938-2940
Total synthesis of modified pentapeptide, caldoramide, a cytotoxic linear pentapeptide from the marine cyanobacterium Caldora penicillate is described. Notable features of the route include the efficient preparation of three key fragments and final assembly to the natural product via sequential amide couplings. The spectral data of the synthetic compound was found to be in comparison with that of the isolated natural product. 相似文献
70.
The one-electron oxidation of toluidine blue by specific oxidising radicals such as Cl
2
−
, Tl(II), N3, Br
2
−
etc. has been studied by employing the pulse radiolysis technique. The Br
2
−
radical was found to be less efficient in oxidising toluidine blue as compared to Cl
2
−
., Tl+2 and N3. The semioxidised species exhibited only onepK
a indicating the presence of two conjugate acid-base forms whose spectral and kinetic features were evaluated. Reaction of
OH radicals with the dye gave rise to a transient species which exhibited spectral and kinetic features different from that
of the semioxidised species indicating that the mode of reaction of OH is different. 相似文献