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71.
Ramesh KotikalapudiK.C. Kumara Swamy 《Tetrahedron letters》2012,53(30):3831-3834
The reaction of 1-hydroxy-2-alkynylallylphosphonates, synthesized by the addition of the corresponding phosphites to 2-alkynylcinnamaldehydes, under AgOTf or Ph3PAuCl-AgSbF6 catalyzed cycloisomerization afforded 2-furylphosphonates in good to excellent yields. These cyclization reactions were compared with those of 2-alkynylallyl alcohols that led to multisubstituted furans. 相似文献
72.
Two methodologies, one involving Ar-I reactivity and the other through C-H functionalization, for the formation of indolo[2,3-c]pyrane-1-ones via the corresponding allenes, are presented. A highly efficient approach to indolo[2,3-c]pyrane-1-one derivatives through the Pd-catalyzed regioselective annulation of allenes with 3-iodo-1-alkylindole-2-carboxylic acids is described. This method is fairly general for a wide range of allenes affording the respective indolo[2,3-c]pyrane-1-ones in good to excellent yields. In addition, a Pd(II)-catalyzed oxidative coupling of indole-2-caboxylic acid derivatives with allenes via direct C-H functionalization to afford the corresponding indolo[2,3-c]pyrane-1-ones in moderate to good yields has been developed. 相似文献
73.
K. C. Kumara Swamy Sudha Kumaraswamy 《Acta Crystallographica. Section C, Structural Chemistry》2001,57(10):1147-1148
The six-membered phosphorinane ring in (1,4,7,10,13,16-hexaoxacyclooctadecane)potassium 2-O-benzoyl-1,3,5-O-methylidyne-myo-inositol 4,6-cyclophosphate trihydrate, [K(C12H24O6)](C14H12O9P)·3H2O, has a boat rather than a chair conformation. The K+ ion is eight-coordinate and is connected to one of the phosphate O atoms, one of the O atoms of the myo-inositol residue and the six O atoms of the crown ether. 相似文献
74.
75.
K. V. P. Pa Van Kumar K. Praveen Kumar M. Vijjulatha K. C. Kumara Swamy 《Journal of Chemical Sciences》2004,116(6):311-317
The compounds S(6-t-Bu-4-Me-C6H2O)2P(O)Cl (1), CH2(6-t-Bu-4-Me-C6H2O)2P(O)Cl (2) and (2,2′-C20H12O2)P(O)Cl (3) react with diazabicycloundecene (DBU) to give rise to, predominantly, the phosphonate compounds [S(6-t-Bu-4-Me-C6H6O)2P(O)(DBU)]+[Cl]− (4), [CH2(6-t-Bu-4-Me-C6H2O)2P(O) (DBU)]+[Cl]− (5) and [(2,2′-C20Hi2O2)P(0)(DBU)]+[Cl]- (6). The first two compounds could be isolated in the pure state. In analogous reactions of 1 and 2 with diazabicyclononene
(DBN) or N-methyl imidazole, only the pyrophosphates [S(6-t-Bu-4-Me-C6H2O)2P(O)]2O (7) and [CH2(6-t-Bu-4-Me-C6H2O)2P(O)]2O (8) could be isolated, although the reaction mixture showed several other compounds in the phosphorus NMR. A possible pathway
for the formation of phosphonate salts is proposed. The X-ray crystal structures of4,7 and8 are also discussed. 相似文献
76.
77.
Bhargav Shreevatsa Chandan Dharmashekara Vikas Halasumane Swamy Meghana V. Gowda Raghu Ram Achar Vivek Hamse Kameshwar Rajesh Kumar Thimmulappa Asad Syed Abdallah M. Elgorban Salim S. Al-Rejaie Joaquín Ortega-Castro Juan Frau Norma Flores-Holguín Chandan Shivamallu Shiva Prasad Kollur Daniel Glossman-Mitnik 《Molecules (Basel, Switzerland)》2021,26(22)
NAD(P)H:quinone acceptor oxidoreductase-1 (NQO1) is a ubiquitous flavin adenine dinucleotide-dependent flavoprotein that promotes obligatory two-electron reductions of quinones, quinonimines, nitroaromatics, and azo dyes. NQO1 is a multifunctional antioxidant enzyme whose expression and deletion are linked to reduced and increased oxidative stress susceptibilities. NQO1 acts as both a tumor suppressor and tumor promoter; thus, the inhibition of NQO1 results in less tumor burden. In addition, the high expression of NQO1 is associated with a shorter survival time of cancer patients. Inhibiting NQO1 also enables certain anticancer agents to evade the detoxification process. In this study, a series of phytobioactives were screened based on their chemical classes such as coumarins, flavonoids, and triterpenoids for their action on NQO1. The in silico evaluations were conducted using PyRx virtual screening tools, where the flavone compound, Orientin showed a better binding affinity score of −8.18 when compared with standard inhibitor Dicumarol with favorable ADME properties. An MD simulation study found that the Orientin binding to NQO1 away from the substrate-binding site induces a potential conformational change in the substrate-binding site, thereby inhibiting substrate accessibility towards the FAD-binding domain. Furthermore, with this computational approach we are offering a scope for validation of the new therapeutic components for their in vitro and in vivo efficacy against NQO1. 相似文献
78.
Alla Siva Reddy Prof. K. C. Kumara Swamy 《Angewandte Chemie (International ed. in English)》2017,56(24):6984-6988
Ethanol is shown to act as a hydrogenating agent for ynamides under palladium catalysis. This behavior is different from the normally expected reaction of ethanol addition to alkynes. The reaction shows stereoselectivity for E enamides, which is in contrast to reports using other hydrogenating sources. The method was also extended to ynamines. Alternatively, the use of ethanol and ammonium formate as the hydrogenating source gives Z enamides. The role of ethanol in hydrogenation was demonstrated by means deuterium labeling experiment. 相似文献
79.
In this paper, we report the molecular mechanics and molecular dynamics studies of the hydration of papain using the AMBER and CHARMm programs. We studied papain in an environment with minimal hydration involving only the X-ray waters and also in the hydrated environment by adding an extra 9 Å layer of water around the residues. The effect of nonbond cutoff was studied by performing minimizations with 8 Å and 15 Å nonbond cutoffs using the program AMBER. Two different solvent models—a constant dielectric and a distance-dependent dielectric—were considered. The AMBER-minimized structure and the average structure obtained from the CHARMm simulations for papain solvated with X-ray waters are presented and compared with the X-ray crystal structure results. Results of a similar comparison of the hydrated structures were also presented. The calculated root mean square deviation between the minimized structure and the X-ray structure is smaller for the hydrated system than for the system hydrated with only the X-ray waters. Results of the molecular mechanics and molecular dynamics simulations were presented for the various regions of papain. The hydration of the active site of papain and the effect of hydration on the torsional motion of the active site residues are presented. © 1996 by John Wiley & Sons, Inc. 相似文献
80.
Y Anjaneyulu R Prabhakar Rao R Y Swamy A Eknath K Narasimha Rao 《Journal of Chemical Sciences》1982,91(2):157-163
A series of mixed ligand complexes of Hg(II) with the general formula Hg (OX) (SA) (where OX: 8-hydroxyquinoline, SA: salicylic,
5-chloro-, 3,5-dibromo, 3,5-diiodo, 3,5-dinitro, acetyl thiosalicylic acids) are isolated in pure state and characterised
by elemental analysis and infrared data. The low molar conductance of the complexes in dimethylformamide indicates non-electrolyte
nature. The antimicrobial activity of these complexes against various bacteria and fungi is studied which indicates that in
several cases, the mixed ligand complexes possess fairly highly antimicrobial activity than the binary mercury-oxinate. The
lipophilic tendency of these complexes and its influence on the antimicrobial activity is critically examined. A probable
mechanism for the toxic action of these complexes against various organisms is discussed. 相似文献