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81.
Pogula Sreekanth Reddy Motakatla Venkata Krishna Reddy Peddiahgari Vasu Govardhana Reddy 《中国化学快报》2016,27(6):943-947
A series of camphor-derived thiourea organocatalysts 3a–f were designed and synthesized from(1R,3S)-camphoric acid 1 and applied to the one-pot three-component Kabachnik–Fields reaction. Catalyst 3c was found to be an efficient organocatalyst for the reaction of 2-cyclopropylpyrimidin-4-carbaldehyde 4,various amines 5, and diphenylphosphite 6 to yield the corresponding enantioselective a-aminophosphonates 7a–e in 74%–82% yields and 14%–35% ee. 相似文献
82.
Priyadarshini Thoppe Sivakumar Sharathna Puthiyaparambath Sanjay Suresh Varma Sasikumar Parameswaran Radhakrishnan Kokkuvayil Vasu 《Journal of heterocyclic chemistry》2021,58(10):1971-1982
The in-situ generation of o-quinone methides and their inverse-electron-demand Diels–Alder reaction in the presence of pentacarboxycyclopentadiene—an organic Brønsted acid—has been reported. The synthesis of xanthenones and chromanones in good to excellent yields from the [4 + 2] cycloaddition of quinone methides with 1, 3-dicarbonyls and Meldrum's acid has been accomplished. The development of this method helps in generating a number of biologically potent heterocycles with medicinal applications. 相似文献
83.
Nucleoside diphosphate kinase (NDPK) has been shown to play a pivotal role in modulating a plethora of cellular processes. In this study, we report on a blue native (BN) PAGE technique which allows the facile assessment of NDPK activity and expression. The in-gel detection of NDPK relies on the precipitation of formazan at the site of immobilized enzyme activity. This is achieved by coupling the formation of ATP, as a consequence of gamma-phosphate transfer from NTP to ADP, to hexokinase (HK), glucose-6-phosphate dehydrogenase (G6PDH), oxidized nicotinamide adenine dinucleotide phosphate (NADP), phenazine methosulfate (PMS), and iodonitrotetrazolium chloride (INT). 2-D denaturing gel analysis confirmed that the activity bands corresponded to NDPK as indicated by subunit composition. Furthermore, the sensitivity and specificity of this readily accessible procedure was assessed by monitoring the in-gel activity of NDPK using different concentrations of GTP and CTP as well as deoxynucleoside triphosphates. This electrophoretic technique allows the quick and easy detection of NDPK, a housekeeping enzyme crucial to cell survival. 相似文献
84.
N‐Substituted N′‐[6‐methyl‐2‐oxido‐1,3,2‐dioxaphosphinino(5,4,‐b)pyridine‐2‐yl]ureas have been accomplished by condensation of equimolar quantities of chlorides of various carbamidophosphoric acids ( 3 ) with 3‐hydroxyl‐6‐methyl‐2‐pyridinemethanol (lutidine diol) ( 4 ) in the presence of triethylamine in dry toluene–tetrahydrofuran (1:1) mixture at 45–50°C. Their structures were established by elemental analyses, IR, 1H NMR, 13C NMR, and 31P NMR spectral data. Their antifungal and antibacterial activity is also evaluated. Most of these compounds exhibited moderate antimicrobial activity in the assays. © 2003 Wiley Periodicals, Inc. Heteroatom Chem 14:509–512, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.10181 相似文献
85.
Vasu K. A. Nirmala A. R. Choudhury S. Mohan J. Saravanan T. Narasimhamurthy 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(12):o676-o678
The two title compounds, 2‐({(1Z)‐[4‐(dimethylamino)phenyl]methylene}amino)‐4,5‐dimethyl‐N‐(2‐methylphenyl)thiophene‐3‐carboxamide, C23H25N3OS, (I), and 2‐({(1E)‐[4‐(dimethylamino)phenyl]methylene}amino)‐N‐(4‐methylphenyl)‐4,5,6,7‐tetrahydro‐1‐benzothiophene‐3‐carboxamide,C25H27N3OS, (II), show antibacterial and antifungal activities. The asymmetric unit of (II) contains two crystallographically independent molecules. The o‐toluidine ring in (I) lies gauche with respect to the thiophene ring. In (II), the p‐toluidine ring is coplanar with the thiophene ring in one molecule, but is tilted from it in the other molecule. Neither structure exhibits any significant intermolecular interactions, but in both, an intramolecular N—H⋯N hydrogen bond forms a pseudo‐six‐membered ring, thus locking the molecular conformation and removing conformational flexibility. 相似文献
86.
We investigated the reaction rates of OH + CH2O → H2O + CHO at CO2 pressures of up to 1000 atm with and without CO2 molecule included in a reactive complex. Both mechanisms begin with formation of the hydrogen-bonded prereactive complexes. Our ab initio calculations indicate a possibility of catalytic effect, predicting an activation barrier that one order of magnitude lower when the CO2 molecule is involved. To verify this effect, we use the Rice–Ramsperger–Kassel–Marcus theory and solve unimolecular master equations in the steady-state approximation. We assume the equilibrium between prereactive complexes and reactants and compare the bimolecular reaction rates for the two mechanisms. The catalyzed reaction mechanism is found to be faster at higher CO2 pressures and lower temperatures, when prereactive complexes have nonnegligible concentration. Therefore, this catalytic effect may be important for this reactive process in room temperature supercritical CO2 solvent, but is unlikely to play a role during oxy-combustion. 相似文献
87.
88.
Ramesh Navudu Gangadhara Rao Mannem Vasu Babu A. Nagababu P. Umamaheswara Rao V. Hari Babu B. 《Research on Chemical Intermediates》2017,43(7):4145-4164
Research on Chemical Intermediates - An improved method was developed for synthesis of 2,4,5-trifluorobenzohydrazide derivatives through condensation of trifluorophenylacetohydrazide with different... 相似文献
89.
Pogula Sreekanth Reddy Peddiahgari Vasu Govardhana Reddy Sura Mallikarjun Reddy 《Tetrahedron letters》2014
2-Cyclopropylpyrimidin-4-yl-aryl/benzothiazole derived α-aminophosphonates were synthesized in a simple and efficient method from a three-component condensation reaction of 2-cyclopropylpyrimidin-4-carbaldehyde, various anilines/benzothiazole amines, and different phosphites by using 0.5 mol % of phosphomolybdic acid (PMA, H3PMo12O40) in dichloromethane at room temperature in good to excellent yields with short reaction times. 相似文献
90.
Transition‐Metal‐Free Synthesis of Carbazoles and Indoles by an SNAr‐Based “Aromatic Metamorphosis” of Thiaarenes
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Dr. M. Bhanuchandra Dr. Kei Murakami Dr. Dhananjayan Vasu Prof. Dr. Hideki Yorimitsu Prof. Dr. Atsuhiro Osuka 《Angewandte Chemie (International ed. in English)》2015,54(35):10234-10238
Dibenzothiophene dioxides, which are readily prepared through oxidation of the parent dibenzothiophenes, undergo nucleophilic aromatic substitution with anilines intermolecularly and then intramolecularly to yield the corresponding carbazoles in a single operation. The “aromatic metamorphosis” of dibenzothiophenes into carbazoles does not require any heavy metals. This strategy is also applicable to the synthesis of indoles. Since electron‐deficient thiaarene dioxides exhibit interesting reactivity, which is not observed for that the corresponding electron‐rich azaarenes, a combination of a thiaarene‐dioxide‐specific reaction with the SNAr‐based aromatic metamorphosis allows transition‐metal‐free construction of difficult‐to‐prepare carbazoles. 相似文献