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1.
M. J. Fernndez J. M. Casares E. Glvez J. Bellanato 《Journal of heterocyclic chemistry》1993,30(3):815-817
The methyl 2,6-diphenyl-1-methyl-4-oxopiperidine-3,5-dicarboxylates 1 were synthesized by the Mannich procedure from methyl 3-oxoglutarate, benzaldehyde and methylamine. Keto-enol tautomerism as well as configurational isomerism at C-2 were observed. The stereochemistry of the Ib and Ic enolic forms were determined by 1H and 13C nmr data. 相似文献
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Schumm BA Koetke DS Adolphsen CE Alexander JP Averill D Barish BC Barklow T Barnett BA Blockus D Boyarski A Brabson B Breakstone A Bulos F Burchat PR Burke DL Cence RJ Chapman J Chmeissani M Cords D Coupal DP Dauncey P DeStaebler HC Dorfan JM Drell PS Drewer DC Durrett D Elia R Feldman GJ Field RC Ford WT Fordham C Frey R Fujino D Gan KK Gero E Gidal G Glanzman T Goldhaber G Gomez Cadenas JJ Gratta G Hanson G Harr R Harral B Harris FA Hayes K Hearty C Heusch CA Hildreth MD Himel T Hinshaw DA 《Physical review D: Particles and fields》1992,46(1):453-456
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In Situ Generation of ArCu from CuF2 Makes Coupling of Bulky Aryl Silanes Feasible and Highly Efficient 下载免费PDF全文
Juan delPozo Prof. Juan A. Casares Prof. Pablo Espinet 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(12):4274-4284
A bimetallic system of Pd/CuF2, catalytic in Pd and stoichiometric in Cu, is very efficient and selective for the coupling of fairly hindered aryl silanes with aryl, anisyl, phenylaldehyde, p‐cyanophenyl, p‐nitrophenyl, or pyridyl iodides of conventional size. The reaction involves the activation of the silane by CuII, followed by disproportionation and transmetalation from the CuI(aryl) to PdII, upon which coupling takes place. CuIII formed during disproportionation is reduced to CuI(aryl) by excess aryl silane, so that the CuF2 system is fully converted into CuI(aryl) and used in the coupling. Moreover, no extra source of fluoride is needed. Interesting size selectivity towards coupling is found in competitive reactions of hindered aryl silanes. Easily accessible [PdCl2(IDM)(AsPh3)] (IDM = 1,3‐dimethylimidazol‐2‐ylidene) is by far the best catalyst, and the isolated products are essentially free from As or Pd (<1 ppm). The mechanistic aspects of the process have been experimentally examined and discussed. 相似文献
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Background
Growth hormone (GH) plays an incompletely understood role in the development of the central nervous system (CNS). In this study, we use transgenic mice expressing a growth hormone antagonist (GHA) to explore the role of GH in regulating postnatal brain, spinal cord and body growth into adulthood. The GHA transgene encodes a protein that inhibits the binding of GH to its receptor, specifically antagonizing the trophic effects of endogenous GH. 相似文献8.
Alonso MA Casares JA Espinet P Soulantica K Orpen AG Phetmung H 《Inorganic chemistry》2003,42(12):3856-3864
The stereochemistry of the chelate rings of a number of rhodium aminophosphine complexes is studied by NMR spectroscopy. The similarity in the variable-temperature behavior for the different compounds is consistent with them having in common highly preferred chelate ring conformations. The six-membered metallacycle of coordinated (R)-PN (PN = o-diphenylphosphino-alpha-methyl-N,N-dimethylbenzylamine) adopts a delta conformation in the solid state. NMR experiments indicate that this conformation is strongly favored in solution as well. The preferred sense of helicity is imposed by the absolute configuration of the stereogenic carbon atom on the ligand, which exerts an important steric control. The complex [Rh(TFB)((C(6)H(4)CHMeNMe(2))(2)P(C(6)H(4)CHMeNHMe(2)))](BF(4))(2).H(2)O.Me(2)CO crystallizes in the monoclinic space group P2(1) with a = 12.0548(11) A, b = 16.139(2) A, c = 12.1804(10) A, beta = 100.742(9) degrees, Z = 4. 相似文献
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Gomez L Slutzky C Ferron J de La Figuera J Camarero J Vazquez De Parga AL de Miguel JJ Miranda R 《Physical review letters》2000,84(19):4397-4400
Generic computer simulations using empiric interatomic potentials suggest a new, collective mechanism that could be responsible for mixing at heteroepitaxial interfaces. Even if single adsorbate atoms diffuse by hopping on the substrate surface and do not mix at the terraces, two-dimensional islands formed by nucleation may become unstable above a certain critical size and explode upwards forming clusters of several atomic layers. This process is accompanied by strong distortions of the underlying atomic layers, and on soft materials it can result in surface etching and incorporation of substrate atoms into the islands. 相似文献
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