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21.
VadimA. Soloshonok Hisanori Ueki Changchun Jiang Chaozhong Cai VictorJ. Hruby 《Helvetica chimica acta》2002,85(11):3616-3623
In this study, we developed a new protocol for the preparation of the chiral 3‐[(E)‐enoyl]‐1,3‐oxazolidin‐2‐ones under the ultimately simple reaction conditions starting with the corresponding enoyl chlorides and 1,3‐oxazolidin‐2‐ones with Et3N/LiCl at room temperature. The method generally allows efficient preparation of various derivatives regardless of the steric and electronic nature of the substituents on both the enoyl or the oxazolidinone sites. Excellent yields, combined with the simplicity of the experimental procedures, render the present method immediately useful for preparing the target compounds. 相似文献
22.
Du
an Uhrín Gyula Batta Victor J. Hruby Paul N. Barlow Katalin E. Kvr 《Journal of magnetic resonance (San Diego, Calif. : 1997)》1998,130(2)
An enhanced version of the X(ω1) half-filtered TOCSY experiment for measurement of long-range heteronuclear coupling constants is proposed which yields high-quality spectra with substantially increased sensitivity and resolution. The modified method features gradient-enhanced X filtering sequences, broadband homonuclear decoupling duringt1, optional1JXHscaling in theF1domain, and gradient coherence selection in combination with the sensitivity-enhanced protocol for the TOCSY transfer. These modifications extend the applicability of the method—coupling constants can be measured accurately for natural abundance samples at low concentrations and for compounds yielding complex spectra. Computer-aided analysis of E.COSY-type multiplets is applied for the determination of heteronuclear long-range coupling constants. 相似文献
23.
Smith EA Coym JW Cowell SM Tokimoto T Hruby VJ Yamamura HI Wirth MJ 《Langmuir : the ACS journal of surfaces and colloids》2005,21(21):9644-9650
The ability of neutral polymer cushions to support neutral lipid bilayers for the incorporation of mobile transmembrane proteins was investigated. Polyacrylamide brush layers were grown on fused silica using atom-transfer radical polymerization to provide polymer layers of 2.5-, 5- and 10-nm thickness. Lipid bilayers composed of POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) were formed by vesicle fusion onto bare fused silica and onto each of the polyacrylamide layers. Bilayer fluidity was assessed by the diffusion of a probe, NBD-labeled phosphatidylcholine, using fluorescence recovery after photobleaching. A transmembrane protein, the human delta-opioid receptor, was inserted into each lipid bilayer, and its ability to bind a synthetic ligand, DPDPE, cyclic[2-d-penicillamine, 5-d-penicillamine]enkephalin, was detected using single-molecule fluorescence spectroscopy by labeling this ligand with a rhodamine dye. The transmembrane protein was observed to bind the ligand for all bilayers tested. The protein's electrophoretic mobility was probed by monitoring the fluorescence from the bound ligand. The 5-nm polyacrylamide thickness gave the fastest diffusion for the fluorescent lipid probe (D(1) = 2.0(+/-1.2) x 10(-7) and D(2) = 1.2(+/-0.5) x 10(-6) cm(2)/s) and also the largest electrophoretic mobility for the transmembrane protein (3 x 10(-8) cm(2)/V.s). The optimum in polymer thickness is suggested to be a tradeoff between decoupling from the substrate and increasing roughness of the polymer surface. 相似文献
24.
Ndungu JM Cain JP Davis P Ma SW Vanderah TW Lai J Porreca F Hruby VJ 《Tetrahedron letters》2006,47(13):2233-2236
In our ongoing research on the synthesis of constrained analogues of CCK/opioid chimeric peptides, a bicyclic dipeptide mimetic for Nle-Asp was designed and synthesized. Starting from β-allyl substituted aspartic acids, the terminal double bond was oxidized resulting in spontaneous cyclization to form racemic hemiaminals. Allylation of the hemiaminals afforded 5-allyl substituted proline analogues, which on oxidation, Horner-Emmons olefination, asymmetric hydrogenation, and bicyclization afforded bicyclic dipeptide mimetics for Nle-Asp. Constrained CCK/opioid peptide analogues containing bicyclic dipeptide mimetics for Nle-Gly, Nle-Asp, and homoPhe-Gly were then synthesized and analyzed at both the CCK and opioid receptors. 相似文献
25.
Diastereoisomers of specifically labeled oxytocin derivatives were resolved using reverse phase high pressure liquid chromatography. The peptides [1-hemi-DL-[alpha-2H]cystine]oxytocin, [6-hemi-DL-[alpha-2H]cystine]oxytocin, [2-DL-[alpha-2H]tyrosine]oxytocin and[8-DL-[2-13C]leucine]oxytocin were readily separated using the conditions described. The diastereoisomers of the oxytocin analog [3-DL-[2-13C]leucine]oxytocin also demonstrated baseline resolution under the same conditions. The procedure offers the investigator a rapid method for screening synthetic oxytocin peptides for undesirable diastereoisomeric by-products. 相似文献
26.
Increased eumelanin expression and tanning is induced by a superpotent melanotropin [Nle4-D-Phe7]-alpha-MSH in humans 总被引:3,自引:0,他引:3
Dorr RT Dvorakova K Brooks C Lines R Levine N Schram K Miketova P Hruby V Alberts DS 《Photochemistry and photobiology》2000,72(4):526-532
Seven normal volunteers (six males and one female) with tanning skin types III or IV (Fitzpatrick scale) were given 10 daily subcutaneous injections of a superpotent synthetic analog of alpha-melanocyte stimulating hormone (alpha-MSH) over two weeks. This agent, [Nle4-D-Phe7]alpha-MSH, also called Melanotan-I (MT-I), was administered at a dose of 0.16 mg/kg/day (Monday-Friday), over a two week period. Tanning was measured serially using computerized light reflectance. This regimen induced tanning at 3 of 8 anatomic sites including the face, neck and forearm by comparison of baseline to (1) the end of the daily dosing period, (day 14), and (2) one week later, (day 21). Shave biopsies of the forearm taken at baseline and day 21 were analyzed by high performance liquid chromatography for eumelanin content which was measured as the permanganate oxidation product, pyrrole-2,3,5-tricarboxylic acid or PTCA. Pheomelanin content was measured as the hydroiodic acid digestion product, aminohydroxyphenylalanine (AHP). Eumelanin was also measured in the forehead skin samples of three subjects. The HPLC results show that mean (+/- SD) baseline eumelanin (PTCA) levels in forehead skin (n = 3) averaged 1.38 (+/- 0.87) ng/mg of wet skin tissue weight. Higher mean baseline levels of PTCA were detected in forearm skin (2.06 +/- 0.28 ng/mg wet weight, n = 7). One week after MT-I treatments ended, there was a mean (SD) 49% (+/- 17.6%) increase in forehead skin PTCA levels compared to baseline (P = 0.019, n = 3, by paired sample T-test). The mean (SD) increase in forearm skin PTCA levels was 98% (+/- 25.4%) over the same period (P = 0.003). In contrast, forearm pheomelanin expression following MT-I treatment did not significantly change from baseline. Overall, the MT-I regimen increased the eumelanin: pheomelanin ratio in forearm skin from 51:1 at baseline to 86:1 following MT-I (P = 0.054 by paired sample T-test). These results show that the tanning induced by MT-I in the face and forearm is associated with a significant increase in the eumelanin content of the human skin. 相似文献
27.
Gary S. Nichol Ruben Vardanyan Victor J. Hruby 《Journal of chemical crystallography》2010,40(11):961-964
Abstract
As part of a study into new Fentanyl-derived opioid compounds with potent analgesic activity and reduced side effects the starting material title compound, C14H21N3O (1), was synthesized and characterized by NMR spectroscopy and single-crystal X-ray diffraction. The crystal structure is monoclinic Cc with unit cell parameters a = 14.1480(3) ?, b = 14.1720(4) ?, c = 27.6701(7) ?, β = 96.956(1)°, α = γ = 90°. The compound has crystallized with four crystallographically unique molecules in the asymmetric unit; each molecule has a very similar conformation and an analysis of the structure shows that although all four unique molecules overlay very well there is no evidence of pseudo-symmetry which would relate the molecules in the higher symmetry space group C2/c. The crystal packing consists of two separate hydrogen bonded chains which are linked together to form a thick 2D structure in the ab plane. 相似文献28.
The asymmetric synthesis of beta-phenyl-substituted cysteine, tryptophan, and serine derivatives was successfully developed. In this approach, the key intermediate, enantiomerically pure 3-phenylaziridine-2-carboxylic ester 7, was prepared from alpha,beta-unsaturated ester 1 by employing the Sharpless asymmetric dihydroxylation. The aziridine 7 was treated with 4-methoxybenzylthiol, indole, and acetic acid to give beta-phenyl-substituted cysteine, tryptophan, and serine, respectively, in a clean S(N)2 type ring opening at the C3 position. This general approach can be used to synthesize a variety of beta-substituted novel amino acids. 相似文献
29.
D. K. Teherani H. Altmann E. Hruby R. Tsanev 《Journal of Radioanalytical and Nuclear Chemistry》1984,85(1):45-55
30 female C57 bl. mice were treated with Adenocarcinoma im. in the right hind leg. Three days later cis-dichlorodiamine platinum was applied orally /15 mg/kg/ to all animals and additional 0.05 mg Prednisolone i.p. to 20 animals. Tissue samples from bloods, livers, kidneys, spleens, hearts, lungs, tumors and gastrointestinal tract were analyzed for their Pt concentration after therapy with cis-dichlorodiammine platinum complexes and Prednisolone by instrumental neutron activation analysis. Even 5 animals were sacrified. The amount of Pt in most of the organs examined remained under 0.05% of the quantity applied. Maximum values were detected at the end of the experiment, except for the gastrointestinal tract, the liver and the kidneys. Treatment of the animals with Prednisolone did not produce a significant different distribution of Pt. Only in tumor tissues a significantly higher amount of Pt was observed after Prednisolone treatment at 48 h but not at 72 h. Blood levels increased with time after Prednisolone treatment, without Prednisolone blood levels decreased. 相似文献
30.
J. Hruby 《Nuclear Physics B》1980,162(3):449-460
The basic results in a new trend in supersymmetry and soliton theory are presented. It is shown that the soliton expectation value of the energy operator is the mass of the soliton without quantum corrections. A new supersymmetric monopole model in three dimensions is constructed by generalization of the supersymmetric sine-Gordon model in one space dimension. 相似文献