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51.
52.
Carlos E.D. NazarioAmanda S. Santana Cristiane Y. KawasokoCarlos A. Carollo Gabriela R. HurtadoLuiz H. Viana Sandro L. BarbosaPalimécio G. Guerrero Jr. Francisco A. MarquesVânia B. Dabdoub Miguel J. DabdoubAdriano C.M. Baroni 《Tetrahedron letters》2011,52(32):4177-4181
Sonogashira cross-coupling reactions involving (E)-iodo vinyl stannanes and terminal acetylenes were carried out in the presence of Pd(PPh3)4, CuI and several amines, affording (Z)-tributylstannyl enynes in moderate to good yields (62-91%). Utilizing the catalytic system containing Pd(PPh3)4 (5%), CuI (10%), and TBAOH (40% in aqueous media) as activator, better yields (72-91%) and lower reaction times were achieved. 相似文献
53.
Strom T Shokati T Klawitter J Klawitter J Hoffman K Schiebel HM Christians U 《Journal of mass spectrometry : JMS》2011,46(7):615-624
SAR-943 (32-deoxo rapamycin) is a proliferation signal inhibitor via interaction with the mammalian target of rapamycin (mTOR). Most importantly, SAR-943 has improved chemical stability compared to rapamycin (sirolimus) and is currently under investigation as a drug coated on coronary stents. It was the goal of this study to identify the SAR-943 metabolites generated after incubation with human liver microsomes using high-resolution mass spectrometry (MS) and MS/iontrap (MS(n)) and comparison of fragmentation patterns of the metabolites with those of SAR-943 and other known rapamycin derivatives. Our study showed that SAR-943 is mainly hydroxylated and/or demethylated by human liver microsomes. The structures of the following metabolites were identified: O-demethylated metabolites: 39-O-desmethyl, 16-O-desmethyl and 27-O-desmethyl SAR-943; hydroxylated metabolites: hydroxy piperidine SAR-943, 11-hydroxy, 12-hydroxy, 14-hydroxy, 23-hydroxy, 24-hydroxy, 25-hydroxy, 46-hydroxy and 49-hydroxy SAR-943; didemethylated metabolites: 16,39-O-didesmethyl and 27,39-O-didesmethyl SAR-943; demethylated-hydroxylated metabolites: 39-O-desmethyl, 23- or 24-hydroxy and 39-O-desmethyl, hydroxy piperidine SAR-943 and dihydroxylated metabolites: 12-,23- or 24-dihydroxy SAR-943. In addition, several other demethylated-hydroxylated and dihydroxylated metabolites were detected. However, their exact structures could not be identified. 相似文献
54.
Elisabeth Holder Gabriele Trapp Jost C. Grimm Volker Schurig Ekkehard Lindner 《Tetrahedron: Asymmetry》2002,13(24):2673-2678
The chiral complex [5-(4-hydroxybutyl)-5′-methyl-2,2′-bipyridine]-bis(1,10-phenanthroline)ruthenium(II)-bis(hexafluoroantimonate) was successfully synthesized and fully characterized by two-dimensional 1H and 13C{1H} NMR techniques (COSY and HMQC) as well as EA- and FAB-MS. A very fast separation of the Δ and Λ enantiomers with excellent efficiency and resolution was achieved by electrokinetic chromatography using anionic carboxymethyl-β-cyclodextrin as a chiral mobile phase additive. The optimum separation conditions were obtained with 50 mM borate buffer at pH 9 and 10 mg/ml of the chiral selector at 20°C. Attempts to separate the well known unmodified tris(2,2′-bipyridine)ruthenium(II) [Ru(bpy)3] complex into its enantiomers under the same conditions were unsuccessful. 相似文献
55.
56.
Roland Prewo Jost H. Bieri Ulrich Widmer Heinz Heimgartner 《Helvetica chimica acta》1981,64(5):1515-1521
Crystal Structure of a Tetrahydro-1(1H)-isoindolone The structure of the tetrahydro-1 (1H)-isoindolone 4a, the product of an intramolecular Diels-Alder addition, has been determined by X-ray analysis. The revised relative configuration of 4a suggests a formation via the exo-transition state of the [4 + 2]-cycloaddition, followed by enolization to the more stable cis-fused product. 相似文献
57.
58.
Lee J.L. Scharer J.E. Jost B.M. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1988,16(6):645-651
Experiments were carried out to verify models of the reflection coefficients and the phase transitions for matched or loaded dielectric-filled waveguide couplers in the ion cyclotron range of frequencies (ICRF). A model for the plasma load simulation in the waveguide is developed and examined permanently using the time-domain features of an HP·8510 network analyzer. The loss properties of deionized water, which was used for laboratory waveguide dielectric tests, are also discussed. Close agreement between the coupling models and measurements is noted. For a matched coupler, the optimal power-coupling efficiency obtained is 95% and for a simulated-plasma loaded coupler this value is in the range of 80%, depending upon the plasma load. If it is assumed that the effects of the high neutron flux present in a reactor environment on the dielectric strength of water are negligible (or eliminated), and that the dielectric breakdown strength of water is approximately 3 kV/cm at nearly 80% coupling efficiency, the power handling capability of the water-filled coupler is estimated to be in the range of 3-6 MW 相似文献
59.
We give a short proof of the Cheeger-Gromoll Splitting Theorem which says that a line in a complete manifold of nonnegative Ricci curvature splits off isometrically. Our proof avoids the existence and regularity theory of elliptic PDE's. 相似文献
60.
We observe in glyoxal cooled in a supersonic free jet the fluorescence of individual rotational levels of the S1 state excited by a cw laser. We use the technique of singlet—triplet magnetic resonance near an anticrossing to measure matrix elements V31 as a function of rotational quantum numbers Ns, Nt, Ks, Kt. The experimental results are compared with theoretical models of singlet—triplet couplings and we show that the spin-vibronic interaction is the dominant singlet—triplet interaction in glyoxal. 相似文献