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101.
Batchu Chandra Sekhar Devalla Venkata Ramana Sukuru Raghu Ramadas 《Journal of heterocyclic chemistry》2001,38(2):383-386
The syntheses of tetracyclic 1,5‐benzoxazepines 3a‐e from heterocyclic (3‐chloroaldehydes 1a‐e and 2‐aminophenol are reported herein (Scheme I). Attempted lithium aluminium hydride (LiAlH4) reduction of the imine double bond in 3a‐e failed to furnish the corresponding saturated compounds 5a‐e. Attempted catalytic hydrogenation of 3a‐e in the presence of acetic acid and acetic anhydride gave surprisingly only the acetoxy derivatives 6a‐e in high yields (Scheme II). Base catalysed hydrolysis of acetoxy derivatives 6a‐e furnished, as expected, the corresponding phenolic derivatives 7a‐e , in moderate yields. Attempted cyclofunctionalization of 3a‐e either with mercaptoacetic acid or its methyl ester to obtain the new penta‐cyclic heterocycles 4a‐e was, however, not successful. 相似文献
102.
Crystallography Reports - The Schiff base, 3-(2-(2-hydroxybenzylidene)hydrazinyl)quinoxalin-2(1H)-one has been synthesized by condensation of 3-hydrazinyl quinoxalin-2(1H)-one and salicylaldehyde... 相似文献
103.
104.
P. Praveen Kumar Y. Dathu Reddy Ch. Venkata Ramana Reddy B. Rama Devi P.K. Dubey 《Green Chemistry Letters and Reviews》2014,7(4):322-329
Green synthesis of novel title compounds (6) has been developed from 3-(1,4-dioxo-3,4-dihydrophthalazin-(1H)-yl)-3-oxopropanenitrile (3) and indole-3-aldehyde (4) using Knoevenagel condensation followed by alkylation with alkylating agents. Compound 6 could also be synthesised by alkylation of 4 followed by condensation with 3. In an alternate sequence of reactions, 6 could be synthesised either from treatment of 3 with N,N-dimethylformamide dimethyl acetal to form (E)-3-(dimethlamino)-2-(1,4-dioxo-1,2,3,4-tetrahydrophthalazine-2-carbonyl)acrylonitrile 8 followed by reaction with 10 or by the reaction 8 with 9 followed by alkylation. 相似文献
105.
The total synthesis of the putative structure of xylarinol B is described and the need to revise its structure is demonstrated. The central benzoxepine skeleton was constructed by employing a cobalt‐mediated bimolecular [2+2+2] Reppe–Vollhardt alkyne cycloaddition reaction. 相似文献
106.
V.M. Soundalgekar T.V. Ramana Murty N.V. Vighnesam 《International Journal of Heat and Fluid Flow》1984,5(1):54-56
Effects of buoyancy forces on forced and free convective flow of water at 4°C past a semi-infinite vertical plate at constant temperature are studied. Flow is assumed to be vertically upwards. Similarity solutions are derived and the resulting equations are solved numerically on a computer. Velocity and temperature profiles are shown graphically and numerical values of the skin friction and the rate of heat transfer are entered in tables. It is observed that the skin friction and the Nusselt number increase with increasing Gr/Re2, where Gr is the Grashof number and Re is the Reynolds number 相似文献
107.
V. V. Atuchin V. A. Kochubey L. D. Pokrovsky V. N. Kruchinin C. V. Ramana 《Optics and Spectroscopy》2014,117(3):423-427
The optical properties of the highly-textured V2O5 thin-films grown on Si(100) by sputter-deposition at various oxygen reactive-pressures were investigated in detail. The profiles of the optical constants, namely the refractive index and extinction coefficient, of V2O5 films were evaluated in the photon-energy range of 1–5 eV. At photon-energy above 2.5 eV, the dispersion behavior in optical constants is explained based on Lorentz-Drude model. The refractive index dispersion fits to a Cauchy’s relation at photon-energy below 2.5 eV, where the V2O5-film is mostly transparent. The optical transitions across the bandgap occur at energy ~2.5–3.2 eV depending on the V2O5 growth conditions and film-microstructure. The highly-textured and c-axis oriented V2O5-films, fabricated under optimum conditions of temperature and oxygen partial pressure, exhibit excellent optical characteristics similar to V2O5 single crystals. 相似文献
108.
The synthesis of orthogonally protected Fmoc‐Dap/Dab (Boc/Z/Alloc)‐OH starting from Fmoc‐Asp/Glu has been described. The salient features of our synthetic strategy involved formation of Fmoc‐Asp/Glu‐5‐oxazolidinone acids, conversion of acid function to acyl azides, Curtius rearrangement, and hydrolysis of the oxazolidinone group. 相似文献
109.
110.