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891.
Bittu Saha Bijeta Mitra Dhiraj Brahmin Biswajit Sinha Pranab Ghosh 《Tetrahedron letters》2018,59(41):3657-3663
This is the first reported, unconventional, efficient strategy for the synthesis of quinoxaline from 2 to iodo benzoic acid and sodium azide in presence of organo Cu (II) catalyst. Herein, a very simple, versatile one pot multi-component protocol for the synthesis of biologically active compound, quinoxaline has been described via Schmidt reaction and the nucleophilic substitution reaction. The isolated compounds were characterized by 1H NMR, 13C NMR. Our reported organo catalyst was characterized by single crystal XRD, SEM. 相似文献
892.
Positivity - In this article, we will prove the existence of infinitely many positive weak solutions to the following nonlocal elliptic PDE. $$\begin{aligned} (-\Delta )^s u&= \frac{\lambda... 相似文献
893.
Jhantu DasSomnath Ghosh 《Tetrahedron letters》2011,52(52):7189-7194
A new synthetic approach toward the synthesis of flavones and pyranoflavone has been developed by light induced intramolecularphotochemicalWittigreaction in water onto aryloxycarbonyl groups and suitably substituted phosphonium bromides sans any phase transfer catalyst or promoter. 相似文献
894.
Priyapratim Patra Saundray Raj Soni Venkata Sundeep Seesala Santanu Dhara Animesh Ghosh Sagar Pal 《Journal of polymer science. Part A, Polymer chemistry》2019,57(15):1697-1703
Biodegradability and biocompatibility are two crucial prerequisites for a promising therapeutic vehicle. Herein, a novel biocompatible copolymer has been synthesized using glycogen and polylactide (PLA). Glycogen, a naturally occurring biopolymer has been functionalized by methacrylation. On the other hand, lactide has been polymerized through ring opening polymerization (ROP), initiated by hydroxyethyl methacrylate (HEMA) and catalyzed by tin (II) 2‐ethyl hexanoate. Finally, the synthesized two substrates (i.e., glycogen methacrylate and PLA‐HEMA) are covalently connected by free‐radical polymerization, initiated by AIBN. The structure of the developed copolymer has been confirmed using 1H and 13C NMR spectral analyses. The gel characteristics have been evaluated by rheological studies, while the morphological assessment has been investigated by FESEM analysis. In vitro cytocompatibility study reveals that the hydrogel (Gly‐co‐PLA) is biocompatible. The in vitro and in vivo release studies demonstrate the excellent pH‐sensitive control release profile of dual drugs: ornidazole and ofloxacin. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1697–1703 相似文献
895.
Sourav Kar Subhash Bairagi Gaurav Joshi Prof. Dr. Eluvathingal D. Jemmis Prof. Dr. Sundargopal Ghosh 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(63):15634-15637
Despite the synthesis and structural characterization of closo-hydroborate dianions, [BnHn]2− (n=6–12) more than 50 years ago, some ambiguity remains about the structure of [B8H8]2−. Although the solid-state structure of [B8H8]2− was established by single-crystal X-ray studies in 1969, fast rearrangements in solution at accessible temperatures prevented its detailed characterization. We therefore stabilized a derivative of [B8H8]2− by using Cp2MBH3 and structurally characterized two new octaborane analogues, [(Cp2MBH3)2B8H6] (Cp=η5-C5H5; M=Zr ( 1-Zr ) and Hf ( 1-Hf )), so that the dynamics of the B8 skeleton were arrested. The solid-state structures of both 1-Zr and 1-Hf comprise a dodecahedron core protected by {Cp2MBH3} moieties on both sides of the cluster. Spectroscopic characterization (11B NMR) validates the intactness of the B8 dodecahedron core in solution as well. Theoretical calculations establish that the two exo-{Cp2MBH3} fragments provide structural and electronic structural stability to the B8 core and its intact dodecahedral dianionic nature. Furthermore, we propose isodesmic equations for the formation of higher analogues of the Bn core (n>8) guarded by different group 4 transition metals. Our analysis suggests that, as we move to higher polyhedra (n>10), the formation becomes unfavourable irrespective of metal. 相似文献
896.
Susanta Lahiri Moumita Maiti Kaustab Ghosh 《Journal of Radioanalytical and Nuclear Chemistry》2013,297(3):309-318
111In is amongst the frequently used radionuclides in diagnostic nuclear medicine. Therefore its production and subsequent separation chemistry have been widely investigated since late 40s. 111In is commonly produced in proton or α-particle induced reactions on cadmium or silver targets. However, in recent past, various heavy ion (7Li, 11B, 12C etc.) activation routes have been proposed for its production. In this mini review, we have tried to portray the production routes of 111In and chemical separation methodologies reported so far in the literature in a concise form. A critical analysis presented in this review will be helpful to select suitable nuclear reaction and radiochemical method to produce high purity 111In for applications. 相似文献
897.
898.
Effect of residual Doppler averaging on the probe absorption in cascade type system: A comparative study
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Suman Mondal Arindam Ghosh Khairul Islam Dipankar Bhattacharyya Amitava Bandyopadhyay 《中国物理 B》2018,(9)
Effect of residual Doppler averaging on the probe absorption in an alkali vapor medium in the presence of a coherent pump beam is studied analytically for the Ξ type system. A coherent probe field is assumed to connect the ground level with the intermediate level whereas a coherent control beam is supposed to act between the intermediate energy level and the uppermost level. Optical Bloch equations(OBE) for a three-level Ξ type system and a four-level Ξ type system are derived by using density matrix formalism. These equations are solved by an analytic method to determine the probe response, which not only depends on the wavelength difference between the control(pump) field and the probe field but shows substantially different features depending on whether the wavelength of the control field is greater than that of the probe field or the reverse. The effect of temperature on probe response is also shown. Enhancement in probe absorption and additional features are noticed under a strong probe limit at room temperature. The four-level Ξ type system has two ground levels and this leads to substantial modification in the simulated probe absorption as compared to the three-level system. 相似文献
899.
Abstract Water assisted supramolecular structures of 2-acetylamino-6-methylpyridine-1-oxide (1) and 1:1 complex of o-phenylenediamine with catechol (2) were determined. The crystal structure of 2-acetylamino-6-methylpyridine-1-oxide. H2O (1), triclinic, a = 7.1276 (6), b = 7.8860 (6), c = 8.9938 (7) Å, α = 100. 143 (2), β = 91.493 (2), γ = 110.972 (1)°, V =462.47 (6) Å3, Z = 2, D calc = 1.323 mg.m?3(293°K) reveals a novel centrosymmetric supramolecular assembly that is sustained by water molecules linking the dimers of pyridine-1-oxide through C—H…O, N—H…O, N+—O? … H hydrogen bonds. The pyridine rings of the dimers are stacked at 3.473 Å apart, involving π- stacking interactions. Complex (2), C6H8N2.—C6 H6O2. 1/2H2O crystallises in the monoclinic space group P2/c: a = 9.0498(2), b = 5.2275(1), c = 25.0771(2) A, β = 97.71°, V= 1175.62(4) Å3, Z = 4. Refinement led to a final conventional R value of 0.041 for 2016 reflections. In these crystals (2), the water molecules lie on the twofold axis and they are linked to the pyrocatechol molecules through an O—H…O hydrogen bond. 相似文献
900.
Optics is regarded undoubtedly a potential and successful candidate in information and data processing because of its inherent
parallelism. In last few decades several all-optical data processors, algebraic processors, arithmetic processors are proposed.
Here in this communication the authors propose a completely new scheme for implementing binary data arithmetic in 2’s Complement
method which is the most advantageous among all other established subtraction methods. To implement it we use non-linear material
massively. 相似文献