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191.
Zusammenfassung 2-l- und 3-d-Pipecolinsäure-Bradykinin wurden nach der üblichenMerrifield-Technik bzw. nach dem Adsorptions-kupplungs-Verfahren vonEsko undKarlsson dargestellt. Dabei wurde die Eignung von Essigsäureanhydrid, 3-Nitrophthalsäureanhydrid und N-Acetylimidazol für die Blockierung während der Synthese freigebliebener Aminogruppen verglichen. 2-l-Pipecolinsäure-bradykinin war biologisch aktiv.
Mit 1 Abbildungen
Abkürzungen entspr. IUPAC-IUB Commission on Biochemical Nomenclature. J. biol. Chem.241, 527, 2491 (1966);Pipec: Pipecolinsäure,DCCI: N,N-Dicyclohexylcarbodiimid,Boc: tert. Butyloxycarbonyl. 相似文献
Solid phase synthesis of 2-l- and 3-d-Pipecolic acid-bradykinin
2-l- and 3-d-Pipecolic acid-bradykinin were synthesized using the general procedure ofMerrifield and the adsorption coupling method ofEsko andKarlsson. Acetic anhydride, 3-nitrophthalic anhydride, and N-acetylimidazole were compared with respect to their efficiency as blocking agents for unreacted amino groups. 2-l-pipecolic acid-bradykinin was biologically active.
Mit 1 Abbildungen
Abkürzungen entspr. IUPAC-IUB Commission on Biochemical Nomenclature. J. biol. Chem.241, 527, 2491 (1966);Pipec: Pipecolinsäure,DCCI: N,N-Dicyclohexylcarbodiimid,Boc: tert. Butyloxycarbonyl. 相似文献
192.
Bal Kishan Dass Siri Krishan Wasan Arthur L Rubin 《Journal of Combinatorial Theory, Series A》1983,34(1):94-97
In this note, the distribution of bursts is obtained, as defined by Chien and Teng, for a linear code and its coset. 相似文献
193.
Shiro Usami Shigeaki Yamada Bal Krishan Puri Masatada Satake 《Mikrochimica acta》1989,97(5-6):263-270
A method was established for the determination of trace amounts of copper using chromatographic preconcentration of copper(I) with 2,4,6-tri(2-pyridyl)-1,3,5-triazine and tetraphenylborate. Copper is quantitatively adsorbed on this adsorbent in the pH range 1.8–10.5 and at flow-rates of 0.2–10 ml/min. The solid mass consisting of copper complex along with naphthalene is dissolved from the column with 5 ml of dimethylformamide. A calibration curve is obeyed over the concentration range 0.2–10.0 g of copper in 5 ml of dimethylformamide. Eight replicate determinations of 3 g of copper gave a mean absorbance of 0.185 with a relative standard deviation of 1.4%. The characteristic concentration for 1% absorption is 0.0143 g/ml (0.103 gmg/ml for direct AAS in aqueous medium). The interference of various ion and salts has been studied and the proposed method has been employed to the determination of copper in biological and water samples. 相似文献
194.
Optically pure α-L -homoproline can be prepared with good yield from N-bnezyloxycarbonyl-L -proline through its diazoketone-derivative. Preparation of derivatives of α-L -homoproline used in peptide chemistry, and of 7-α-L -homoproline-bradykinin, as well as biological investigation of the latter are described. 相似文献
195.
Meyers C Maes BU Loones KT Bal G Lemière GL Dommisse RA 《The Journal of organic chemistry》2004,69(18):6010-6017
Evidence for an interphase deprotonation of Pd(II)-amine complexes with weak carbonate base has been gained for the first time. When a rate-limiting deprotonation step is involved in the catalytic cycle, controlling the structure (shape and size of the particles) and/or molar excess of the carbonate base used can significantly increase the reaction rate of Buchwald-Hartwig aminations. By taking such a "base effect" into account a general protocol for the intermolecular amination of aryl iodides with all types of amines has been developed based on a standard Pd-BINAP catalyst, using cesium carbonate as the base. 相似文献
196.
Márta Porcs-Makkay Balázs Volk Rita Kapiller-Dezsófi Tibor Mezei Gyula Simig 《Monatshefte für Chemie / Chemical Monthly》2004,26(5):697-711
A new, practical synthesis of the antirheumatic oxindole derivative, tenidap, has been elaborated. The new approach has initiated studies on the mechanism of the acylation reactions of oxindoles. Methods have been developed for the synthesis of 1-[alkoxy(or aryloxy)carbonyl]- and 1,3-di[alkoxy(or aryloxy)carbonyl]oxindoles starting from oxindoles. The route designed for tenidap has provided a facile access to several analogues, too.On another front, new reaction conditions are described, which turn Wenkerts synthesis of 3-alkyloxindoles (by Raney nickel induced alkylation of oxindoles with alcohols) into a highly efficient synthetic tool. The method has been extended to the synthesis of 3-alkyloxindoles from isatins and to the preparation of 3-(-hydroxyalkyl)oxindoles from oxindoles and isatins. 相似文献
197.
J C Széles B Csapó M Klarh?fer C Balássy R Hoda A Berg M Roden P Polterauer W Waldh?usl E Moser 《Magnetic resonance imaging》2001,19(9):1235-1238
The feasibility of in vivo high-resolution magnetic resonance micro-imaging of fine anatomic structures of human toes was tested. Five healthy subjects were investigated on an experimental 3 Tesla whole body scanner, using standard 3D gradient echo sequences. A radio-frequency surface coil was used for signal detection. Feet, toes and surface coil were comfortably fixed using a home built device for positioning and reduction of motion artifacts. The spatial resolution of 117 x 313 x 375 microm(3) allowed detailed visualization of anatomic structures like skin layers, vessels and nerves. In addition, oval structures with diameters ranging from 500 to 1000 microm were observed in all subjects, which could represent the sensory nerve endings of Vater-Pacinian bodies. Thus, high resolution MR micro-imaging at 3 Tesla may provide improved morphologic information in distal extremities of humans in vivo. 相似文献
198.
Seed laser pulses with average power of 146 μW and pulse duration of 480 fs were amplified to 14.5 mW. The pulse duration
was compressed to 260 fs using 6 m high concentration E3+
r -doped fiber under forward pumping. The amplified signal pulse energy was 0.691 nJ (corresponding to a peak power of 2 657.7
W) and the repetition rate was 20.84 MHz. Spectrum breakup was observed simultaneously. The spectrum of pulses amplified by
3 m E3+
r -doped fiber remains a single peak under different pump power. The amplified pulse duration was compressed abnormally with
the increasing pump power using the backward pumping; that is, the amplified pulses were compressed with the increasing pump
power under low pump power. When the pump power reached 38 mW, the shortest amplified pulse duration was 309 fs. With further
increase in pump power, the amplified pulses began broadening, accompanied by a single peak spectrum under different pump
power. 相似文献
199.
Prof. Peter Baláž Dr. Erika Dutková Dr. Matej Baláž Dr. Róbert Džunda Dr. Jiří Navrátil Dr. Karel Knížek Dr. Petr Levinský Dr. Jiří Hejtmánek 《ChemistryOpen》2021,10(8):806-814
Chalcopyrite CuFeS2, a semiconductor with applications in chemical sector and energy conversion engineering, was synthetized in a planetary mill from elemental precursors. The synthesis is environmentally friendly, waste-free and inexpensive. The synthesized nano-powders were characterized by XRD, SEM, EDX, BET and UV/Vis techniques, tests of chemical reactivity and, namely, thermoelectric performance of sintered ceramics followed. The crystallite size of ∼13 nm and the strain of ∼17 were calculated for CuFeS2 powders milled for 60, 120, 180 and 240 min, respectively. The evolution of characteristic band gaps, Eg, and the rate constant of leaching, k, of nano-powders are corroborated by the universal evolution of the parameter SBET/X (SBET-specific surface area, X-crystallinity) introduced for complex characterization of mechanochemically activated solids in various fields such as chemical engineering and/or energy conversion. The focus on non-doped semiconducting CuFeS2 enabled to assess the role of impurities, which critically and often negatively influence the thermoelectric properties. 相似文献
200.
Journal of Nanoparticle Research - To date very little studies are available in the literature on the interaction of Al2O3 nanoparticles with multidrug-resistant strains of Staphylococcus aureus.... 相似文献