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631.
632.
Nagaraju Kerru Sandeep V. H. S. Bhaskaruni Lalitha Gummidi Surya Narayana Maddila Suresh Maddila 《合成通讯》2013,43(19):2437-2459
Among the bioactive heterocyclic frameworks, nitrogen containing multisubstituted imidazoles are versatile building blocks of many naturally occurring products. Imidazoles possess wide range of biological properties including anticancer, anti-inflammatory, antimicrobial, and antihypertensive activities with potential applications in other sectors. Multicomponent reactions in combination with heterogeneous catalysts and nanocomposites have contributed significantly to organic synthesis in general and imidazoles, in particular with high functional group tolerance. Owing to their tunable properties, lower operational cost, thermal stability, recyclability, and easily separation from products, heterogeneous catalysts and nanocomposites are integral part of numerous pharmaceutical, agrochemical, and industrial processes. There has been increased focus on the development of green and sustainable catalytic procedures for the building of novel and biologically potent imidazole conjugates. This article emphasizes the recent advances in recyclable catalysts and protocols, and their merits for the synthesis of diverse multisubstituted imidazole conjugates by one-pot reaction approach and the catalyst and reactant interactions. 相似文献
633.
G. Krishnaiah B. Sandeep D. Kondhare K.C. Rajanna J. Narendar Reddy Y. Rajeshwar Rao P.K. Zhubaidha 《Tetrahedron letters》2013,54(7):703-706
Transesterification of β-ketoesters with various alcohols has been studied under conventional and non-conventional conditions using desktop chemicals such as Mn(II) salts as catalysts. These methods offered transesterification of β-ketoesters in good yields with dramatic rate accelerations and reduced reaction times. The developed protocols under nonconventional methods such as sonication and microwave irradiation are highly promising compared with the existing procedures. 相似文献
634.
Sandeep P. Patil Yousef Heider Carlos Alberto Hernandez Padilla Eduardo Cruz-Chú Bernd Markert 《PAMM》2016,16(1):139-140
In order to better understand and ease the determination of material and model parameters required for the macroscopic modelling of brittle fracture, a bottom-up comparative study between molecular dynamics (MD) simulations and the continuum phase-field modelling (PFM) is carried out. In particular, based on the MD simulations of fracture of a highly brittle material, a number of PFM parameters such as the width of the transition zone between the damaged and the undamaged material, the crack resistance and the elasticity modulus are estimated. This study opens the door for an efficient way for multi-scale modelling of fracture. To illustrate this approach, a comparative two-dimensional numerical initial-boundary-value problem (IBVP) for the highly brittle aragonite (CaCO3) is presented. (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
635.
In this review, we summarize advances in [4+3] and a few other annulation/cycloaddition reactions for the construction of seven membered rings, with an emphasis on the literature subsequent to the year 2010. The type of products include the following: azepines, diazepines, benzazepinones, 1,2‐diazepinones, oxazepinones, benzothiazepines, benzodiazepinones, benzoxopinones, cyclohepta[b]indoles, benzoxazepines, azepino‐indoles, oxepines/oxazepanes, triazepines oxepinoindolones/azepinoindolones, oxadiazepines, azabicyclooctanes. Emphasis is also given to cover diverse types of annulations; possible intermediates are displayed in the illustrated schemes to aid future work. 相似文献
636.
Rohit Kumar Sandeep Yadav Kritika Gour Ekta Sangtani Soumya Ranjan Dash Abhishekram Raja Kumar Vanka Rajesh G. Gonnade Sakya S. Sen 《化学:亚洲杂志》2020,15(6):820-827
In this paper, we have used two N,O‐ketiminato ligands ( L1 and L2 ) with biphenyl and terphenyl substituent on the nitrogen atom. Deprotonation of L1 with KN(SiMe3)2 and subsequent reaction with MgI2 led to a homoleptic dinuclear magnesium complex ( 1 ) with a Mg2O2 four‐membered ring. Deprotonation with nBuLi and subsequent reaction with MgI2 afforded a unusual dinuclear magnesium complex ( 2 ) with a Mg2O2 ring. Extension of the ligand for calcium resulted in a trinuclear calcium complex ( 3 ) with six four‐membered Ca2O2 rings. We could not isolate any chelating complex when L2 was used as a ligand, and only oxygen bound magnesium ( 4 ) and calcium ( 5 ) adducts were isolated. DFT studies were performed to understand this dissimilar behavior. More diverse results were obtained when lithiated L1 and L2 were treated with germanium dichloride. We were able to stabilize a monomeric germylene monochloride ( 7 ) with L1 . However, with L2 , an unusual ligand scrambling, and a C?C coupling take place, leading to the formation of a secondary carbocation with GeCl3‐ as a counter‐anion ( 8 ). Besides, a germanium dichloride adduct ( 9 ) bound to the oxygen center of the ligand was obtained as the minor product. 相似文献
637.
Ravindra N. Bulakhe Sandeep A. Arote Binhee Kwon Seongmin Park Insik In 《Materials Today Chemistry》2020
A facile synthesis of nickel cobalt sulfide (NCS) nanoflowers have been deposited successfully onto binder free 3D nickel foam electrodes using simple successive ionic layer adsorption and reaction (SILAR) method for supercapacitor applications. The obtained NCS nanoflowers manifest ultrahigh specific capacitance of 1899 F g?1 at a scan rate of 5 mV s?1. The NCS nanoflowers exhibit a prominent energy density of 55.16 Wh kg?1 at power density of 495 W kg?1 and superior cyclic stability of 94% after 10000 cycles. In addition, the asymmetric supercapacitor (ASC) device is fabricated using NCS nanoflower as positive and reduced graphene oxide (rGO) as negative electrodes, respectively. The ASC (NCS//rGO) delivered good capacity with excellent energy and power densities within 1.6 V wider potential window. Hence, NCS nanoflowers are an outstanding material for energy storage applications in near future. 相似文献
638.
AbstractA protocol based on Groebke-Blackburn-Bienayame (GBB) multicomponent reaction has been developed for efficient and atom economical synthesis of C-glucosides of 1-azaindolizine, i.e. 2-(β-D-glucopyranosyl)-3-N-alkylamino-1-azaindolizine. Thus, a series of fourteen novel 2-(β-D-glucopyranosyl)-3-N-alkylamino-1-azaindolizines have been synthesized in moderate to good yields by reaction of a perbenzylated β-C-glucopyranosyl aldehyde with differently substituted 2-aminopyridines and alkyl isocyanides using InCl3 as acid catalyst. All synthesized β-C-glucosides were unambiguously characterized with the help of spectroscopic (IR, 1H-NMR, 13C-NMR and mass spectra) data analysis. 相似文献
639.
Diptirani Rath Sandeep Kumar Panigrahi Durga Madhab Kar Laxmidhar Maharana 《Natural product research》2018,32(16):1977-1981
The GC-MS analysis of fractions of methanol extract of stem of Cuscuta reflexa (Family Convolvulaceae) was carried out using a THERMO TRACE 1300 Gas Chromatograph equipped and coupled to a mass detector THERMO TSQ 8000 spectrometer with an TG 5MS (30 m × 0.25 mm, 0.25 μm) of capillary column. Database of National Institute of Standards and Technology (NIST) library was used to identify the components. GC-MS revealed two known compounds i.e. 2-Methoxy-4-vinyl phenol (6.80%) and Benzofuran-2,3-dihydro (20.89%) and other 12 unknown compounds such as 3,5-di-tert-Butyl-4-hydroxyanisole (35.50%); Hexatriacontane (12.02%); n-Hexadecanoic acid (10.12%); Scoparone (7.97%); Hexadecanoic acid methyl ester (5.22%); 1,3-Benzenediamine, N, N, N′, N′ tetramethyl- (15.43%); Phenol, 4(3-hydroxy1propenyl), 2-methoxy (9.31%); Phenol, 2,4 bis (1,1dimethylethyl); 2,3,5,6-Tetramethyl para phenylene diamine (14.18%); Retinoic acid-5,6-epoxy-5,6-dihydro (20.46%); 2,4-Dihydroxy-2,5-dimethyl-3(2H)furan-3-one (10.13%); 2,3-dihydro-3,5-dihydroxy-6-methyl-2-Propyl-tetrahydro-pyran-3-ol (10.13%); Pregn-4-ene-18-oic acid (5.75%) as some of the major compounds in its different fractions. Retinoic acid-5,6-epoxy-5,6-dihydro found as major compound may be responsible for blood glucose lowering potency. 相似文献
640.
Niloofar Abolhasani Khaje Charles K. Mobley Sandeep K. Misra Lindsey Miller Zixuan Li Evgeny Nudler Joshua S. Sharp 《Journal of the American Society for Mass Spectrometry》2018,29(9):1901-1907
Fast photochemical oxidation of proteins (FPOP) may be used to characterize changes in protein structure by measuring differences in the apparent rate of peptide oxidation by hydroxyl radicals. The variability between replicates is high for some peptides and limits the statistical power of the technique, even using modern methods controlling variability in radical dose and quenching. Currently, the root cause of this variability has not been systematically explored, and it is unknown if the major source(s) of variability are structural heterogeneity in samples, remaining irreproducibility in FPOP oxidation, or errors in LC-MS quantification of oxidation. In this work, we demonstrate that coefficient of variation of FPOP measurements varies widely at low peptide signal intensity, but stabilizes to ≈?0.13 at higher peptide signal intensity. We dramatically reduced FPOP variability by increasing the total sample loaded onto the LC column, indicating that the major source of variability in FPOP measurements is the difficulties in quantifying oxidation at low peptide signal intensities. This simple method greatly increases the sensitivity of FPOP structural comparisons, an important step in applying the technique to study subtle conformational changes and protein-ligand interactions. 相似文献