Search results for "Oxamide"
showing 7 items of 227 documents
Non-covalent interactions of N-phenyl-1,5-dimethyl-1H-imidazole-4-carboxamide 3-oxide derivatives—a case of intramolecular N-oxide hydrogen bonds
2017
The crystal structures of new N-phenyl-1,5-dimethyl-1H-imidazole-4-carboxamide 3-oxide derivatives are reported. The results of X-ray diffraction showed the existence of intramolecular hydrogen bonding between carboxamide nitrogen donors and N-oxide oxygen acceptors. The use of Quantum Theory of Atoms in Molecules allowed its classification as a strong interaction, with energy about 10 kcal/mol, and of intermediate character between closed shell and shared bonds. Comparison of experimental data and quantum theoretical calculations indicated that a substituent attached to the phenyl ring in the para position influences the strength and geometry of the title hydrogen bonding. Stronger π-elect…
Design, synthesis, DNA-binding and cytotoxicity evaluation of new potential combilexines
2002
Combilexines, compounds in which a DNA intercalator is linked to a minor groove binding component, interact with the DNA in a sequence specific manner to yield in most cases compounds with anticancer activity. A series of new compounds closely related to netropsin in which the two components were linked by an amide group was synthesised as potential combilexines. As some of these compounds showed cytotoxic activity in vitro, an attempt was made to rationalise their mechanism of action. The DNA binding characteristics of the carboxamides were evaluated by thermal denaturation experiments and by ethidium bromide displacement assay. Their ability to inhibit the topoisomerase I was also determi…
Synthesis, biological evaluation, and structure-activity relationship study of novel cytotoxic aza-caffeic acid derivatives.
2010
Abstract Three series of aza-caffeic acid derivatives with different linkers were designed and synthesized. Each of the synthesized derivatives was then used in cytotoxicity screening on either 8 or 12 human cancer cell lines. The structure–activity relationships on three structural regions A, B, and C are analyzed in detail, indicating that a nine bond linker B, containing a piperazine unit, is the most favorable linker leading to the generation of molecules with potent cytotoxicities. Compound ( E )-1-(4-(3,4-dichlorobenzyl)piperazin-1-yl)-3-(4-(4-ethoxybenzyloxy)-3,5-dimethoxyphenyl)prop-2-en-1-one ( 80 ) exhibited the most significant and selective cytotoxicity to KB, BEL7404, K562, and…
Synthesis of fluorine-18 labeled sulfonureas as ?-cell imaging agents
2001
Tolbutamide (1) and glyburide (7) are hypoglycemic drugs used to stimulate insulin secretion in type 2 diabetic patients. We have synthesized their fluorine-18 labeled analogs, 1-[(4-[ 18 F]fluorobenzenesulfonyl)]-3-butyl]urea (p-[ 18 F]fluorotolbutamide, 3a) and N-{4-[β-(2-[ 18 F]fluoroethoxybenzene carboxamido)ethyl]benzenesulfonyl)-N'-cyclohexylurea (2-[ 18 F]fluoroethoxyglyburide, 6a) as β-cell imaging agents. Compound 3a was synthesized via two approaches: One-step synthesis via nucleophilic substitution of p-nitrotolbutamide (2) with K[ 18 F]/Kryptofix 2.2.2 in either CH 3 CN or DMSO gave a complicated mixture; a two-step synthesis via preparation and reaction of 4-[ 18 F]fluorobenzen…
Characterization of adenosine receptors in guinea-pig isolated left atria
1989
1. The effects of purinergic stimulation on action potential, force of contraction, 86Rb efflux and 45Ca uptake were investigated in guinea-pig left atria. 2. Adenosine exerted a negative inotropic effect which was antagonized by adenosine deaminase but enhanced by dipyridamole. 3. The negative inotropic effect of adenosine was mimicked by 5'-(N-ethyl)-carboxamido-adenosine (NECA) and the isomers of N6-(phenyl-isopropyl)-adenosine, R-PIA and S-PIA. NECA and R-PIA were about 100 times more potent than adenosine, whereas R-PIA was about 100 times more potent than S-PIA. 4. The inotropic effects of adenosine (in the presence of dipyridamole), NECA, R-PIA and S-PIA were competitively antagonize…
Adrenoceptor-mediated effects on calcium channel currents are antagonized by 5?-(N-ethyl)-carboxamido-adenosine in guinea-pig atrial cells
1992
In guinea-pig atrial myocytes, the effects of the adenosine analogue 5′-(N-ethyl)-carboxamido-adenosine (NECA) in the presence of isoprenaline (ISO) on Ca2+ channel activity were analyzed. Single Ca2+ channel currents were recorded from cell-attached patches by application of several hundred 100 ms depolarizing steps. Under control conditions, burstlike activity of channel openings during some depolarizing steps were followed by variably long periods of quiescence (blank sweeps). During superfusion with ISO (100 nmol/l), ensemble-averaged (mean) current was increased by about 150%. The underlying mechanism was found to be a significant increase in the channel availability, defined as the ra…
CCDC 991416: Experimental Crystal Structure Determination
2015
Related Article: Mithun Das, Bikash Kumar Shaw, Biswa Nath Ghosh, Kari Rissanen, Shyamal Kumar Saha, Shouvik Chattopadhyay|2015|RSC Advances|5|46869|doi:10.1039/C5RA07548C