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61.
Hurlocker B Abascal NC Repka LM Santizo-Deleon E Smenton AL Baranov V Gupta R Bernard SE Chowdhury S Rojas CM 《The Journal of organic chemistry》2011,76(7):2240-2244
By using (N-tosyloxy)-3-O-carbamoyl-D-glucal 10, which removes the need for a hypervalent iodine(III) oxidant, we provide evidence for rhodium nitrenoid-mediated ipso C-H activation as the origin of a C3-oxidized dihydropyranone product 3. This system may be especially susceptible to such a pathway because of the ease of forming a cation upon hydride transfer to the rhodium-complexed acyl nitrene. 相似文献
62.
Pushkal Samadhiya Ritu Sharma Santosh K. Srivastava Savitri D. Srivastava 《中国化学》2011,29(5):1001-1010
Conventional and microwave assisted synthesis of new series of N‐[2‐{2‐(substituted phenyl)‐4‐oxo‐5‐(substituted benzylidene)‐1,3‐thiazolidine}‐iminoethyl]‐2‐aminothiazole 5a–5m have been developed. The cycloaddition reaction of thioglycolic acid with N‐{2‐(substituted benzylidenehydrazino)‐ethyl}‐2‐aminothiazole 3a–3m in the presence of anhydrous ZnCl2 afforded new heterocyclic compounds N‐[2‐{2‐(substituted phenyl)‐4‐oxo‐1,3‐thiazolidine}‐iminoethyl]‐2‐aminothiazole 4a–4m . The later product on treatment with several selected substituted aromatic aldehydes in the presence of C2H5ONa undergoes Knoevenagel reaction to yield 5a–5m . The structures of compounds 1 , 2 , 3a–3m , 4a–4m and 5a–5m were confirmed by IR, 1H NMR, 13C NMR, FAB‐Mass and chemical analysis. All above compounds were screened for their antimicrobial activities against some selected bacteria and fungi and antituberculosis study against M. tuberculosis. 相似文献
63.
Naik PK Lopus M Aneja R Vangapandu SN Joshi HC 《Journal of computer-aided molecular design》2012,26(2):233-247
Our screen for tubulin-binding small molecules that do not depolymerize bulk cellular microtubules, but based upon structural
features of well known microtubule-depolymerizing colchicine and podophyllotoxin, revealed tubulin binding anti-cancer property
of noscapine (Ye et al. in Proc Natl Acad Sci USA 95:2280–2286, 1998). Guided by molecular modelling calculations and structure–activity relationships we conjugated at C9 of noscapine, a folate
group—a ligand for cellular folate receptor alpha (FRα). FRα is over-expressed on some solid tumours such as ovarian epithelial
cancers. Molecular docking experiments predicted that a folate conjugated noscapine (Targetin) accommodated well inside the
binding cavity (docking score −11.295 kcal/mol) at the interface between α- and β-tubulin. The bulky folate moiety of Targetin
is extended toward lumen of microtubules. The binding free energy (ΔG
bind) computed based on molecular mechanics energy minimization was −221.01 kcal/mol that revealed favourable interaction of Targetin
with the receptor. Chemical synthesis, tubulin-binding experiments, and anti-cancer activity in vitro corroborate fully well
with the molecular modelling experiments. Targetin binds tubulin with a dissociation constant (K
d value) of 149 ± 3.0 μM and decreases the transition frequencies between growth and shortening phases of microtubule assembly
dynamics at concentrations that do not alter the total polymer mass. Cancer cells in general were more sensitive to Targetin
compared with the founding compound noscapine (IC50 in the range of 15–40 μM). Quite strikingly, ovarian cancer cells (SKOV3 and A2780), known to overexpress FRα, were much
more sensitive to targetin (IC50 in the range of 0.3–1.5 μM). 相似文献
64.
Rajni Sharma Ritu Bala Andrew D. Bond Raj Pal Sharma 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(6):m272-m274
In the title compound, [Co(N3)2(C2H8N2)2](C6H2N3O7), the cations share NH2⋯NH2 edges with picrate anions via second‐sphere N—H⋯O hydrogen bonds. 相似文献
65.
The new approach involving the solid supported catalyst for the formation of C–N bond followed by cyclization has been reported. In this work we have reported a facile, efficient, and environment‐friendly protocol for the synthesis of some new 3‐amino‐imidazo[2,1‐b](1,3)benzothiazole derivatives by one‐pot condensation of 2‐aminobenzothiazole, indole‐3‐carbaldehyde, and aryl isocyanide in the presence of silica‐supported P2O5 as a heterogeneous solid acid catalyst. The reaction was performed using conventional method under green conditions. The present approach offers the advantages of simple methodology, inexpensive acid catalyst, short reaction time, easy work up with excellent yield, simple purification and use of green solvent. All the newly synthesized compounds were characterized in details using physical and chemical techniques such as melting point, 1H NMR, 13C NMR, and FTIR spectroscopy. 相似文献
66.
Ritu Bala Raj Pal Sharma Upendra Sharma Valeria Ferretti 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(12):m628-m631
In the title complex salt, tetrakis[hexaamminecobalt(III)] hexachlorocadmate(II) bis[aquatetrachlorothiocyanatocadmate(II)] dichloride dihydrate, the discrete ions, i.e. [Co(NH3)6]3+, Cl−, [CdCl6]4− (located on an inversion centre) and [CdCl4(SCN)(H2O)]3−, together with cocrystallized water molecules, are assembled by means of a network of hydrogen‐bonding interactions. This is the first X‐ray structure determination of a hexaamminecobalt(III) salt with two different complex chlorocadmium anions. 相似文献
67.
Dr. Thomas B. Parsons Keisuke Yamamoto Thomas A. Taylor Ritu Raj Kim Wals Prof. Shabaz Mohammed Prof. Carol V. Robinson Prof. Justin L. P. Benesch Prof. Benjamin G. Davis 《Angewandte Chemie (International ed. in English)》2016,55(7):2361-2367
Glycosylation patterns in antibodies critically determine biological and physical properties but their precise control is a significant challenge in biology and biotechnology. We describe herein the optimization of an endoglycosidase‐catalyzed glycosylation of the best‐selling biotherapeutic Herceptin, an anti‐HER2 antibody. Precise MS analysis of the intact four‐chain Ab heteromultimer reveals nonspecific, non‐enzymatic reactions (glycation), which are not detected under standard denaturing conditions. This competing reaction, which has hitherto been underestimated as a source of side products, can now be minimized. Optimization allowed access to the purest natural form of Herceptin to date (≥90 %). Moreover, through the use of a small library of sugars containing non‐natural functional groups, Ab variants containing defined numbers of selectively addressable chemical tags (reaction handles at Sia C1) in specific positions (for attachment of cargo molecules or “glycorandomization”) were readily generated. 相似文献
68.
69.
Emulsification at the Liquid/Liquid Interface: Effects of Potential,Electrolytes and Surfactants
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Emulsification of oils at liquid/liquid interfaces is of fundamental importance across a range of applications, including detergency. Adsorption and partitioning of the anionic surface active ions at the interface between two immiscible solutions is known to cause predictable chaos at the transfer potential region of the surfactant. In this work, the phenomenon that leads to the chaotic behaviour shown by sodium dodecylbenzene sulfonate (SDBS) at the water/1,2‐dichloroethane interface is applied to commercial surfactants and aqueous/glyceryl trioleate interface. Electrochemical methods, electrocapillary curves, optical microscopy and conductivity measurements demonstrated that at 1.5 mm of SDBS, surfactants are adsorbed at the interface and assemble into micelles, leading to interfacial instability. As the concentration of the anionic surfactant was enhanced to 8 and 13.4 mm , the Marangoni effect and the interfacial emulsification became more prominent. The chaotic behaviour was found to be dependent on the surfactant concentration and the electrolytes present. 相似文献
70.
Ulrike Wirth Julia Erl Saphia Azzam Dr. Carina Höring Dr. Michael Skiba Ritu Singh Kathrin Hochmuth PD Dr. Max Keller Prof. Dr. Joachim Wegener Prof. Dr. Burkhard König 《Angewandte Chemie (International ed. in English)》2023,62(21):e202215547
G protein-coupled cell surface receptors (GPCR) trigger complex intracellular signaling cascades upon agonist binding. Classic pharmacological assays provide information about binding affinities, activation or blockade at different stages of the signaling cascade, but real time dynamics and reversibility of these processes remain often disguised. We show that combining photochromic NPY receptor ligands, which can be toggled in their receptor activation ability by irradiation with light of different wavelengths, with whole cell label-free impedance assays allows observing the cell response to receptor activation and its reversibility over time. The concept demonstrated on NPY receptors may be well applicable to many other GPCRs providing a deeper insight into the time course of intracellular signaling processes. 相似文献