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排序方式: 共有362条查询结果,搜索用时 15 毫秒
81.
Dr. Dirk Alpers Dr. Kevin P. Cole Prof. Dr. Corey R. J. Stephenson 《Angewandte Chemie (International ed. in English)》2018,57(37):12167-12170
The photocatalytic preparation of aminoalkylated heteroarenes from haloalkylamides via a 1,4‐aryl migration from nitrogen to carbon, conceptually analogous to a radical Smiles rearrangement, is reported. This method enables the substitution of amino groups in heteroaromatic compounds with aminoalkyl motifs under mild, iridium(III)‐mediated photoredox conditions. It provides rapid access to thienoazepinone, a pharmacophore present in multiple drug candidates for potential treatment of different conditions, including inflammation and psychotic disorders. 相似文献
82.
83.
84.
Darin R. Stephenson 《Transactions of the American Mathematical Society》1997,349(6):2317-2340
This paper completes the classification of Artin-Schelter regular algebras of global dimension three. For algebras generated by elements of degree one this has been achieved by Artin, Schelter, Tate and Van den Bergh. We are therefore concerned with algebras which are not generated in degree one. We show that there exist some exceptional algebras, each of which has geometric data consisting of an elliptic curve together with an automorphism, just as in the case where the algebras are assumed to be generated in degree one.
In particular, we study the elliptic algebras , , and , where , which were first defined in an earlier paper. We omit a set consisting of 11 specified points where the algebras become too degenerate to be regular. Theorem. Let represent , or , where . Then is an Artin-Schelter regular algebra of global dimension three. Moreover, is a Noetherian domain with the same Hilbert series as the (appropriately graded) commutative polynomial ring in three variables.
This, combined with our earlier results, completes the classification.85.
86.
Ulrich Klages Walter Kuhn David S. Stephenson Gerhard Binsch Mathias Noltemeyer Ernst Egert George M. Sheldrick 《Tetrahedron》1984,40(21):4337-4349
The synthesis, structure and dynamics of hexaspiro[2.0.3.0.2.0.3.0.- 2.0.3.0]heneicosane are described. adopts a chair conformation in the crystal state but prefers a chair-to-twistboat equilibrium in solution. The activation parameters of the chair-to-chair interconversion of and the closely related hexaspiro[2.0.2.0.2.0.2.0.2.0.2.0]- octadecane ([6]rotane) have been determined by DNMR. Some consequences appertaining to the conformation and dynamics of other fully (cyclo-)alkylated cyclohexanes are discussed. 相似文献
87.
Philip W. Howard G. Richard Stephenson
Stephen C. Taylor
《Journal of organometallic chemistry》1989,370(1-3):97-109Homochiral 6-methoxy-substituted dienyltricarbonyliron complexes have been obtained from 1-methylcyclohexa-1,3-diene-5,6-diol (available via microbial oxidation of toluene) by complexation and removal of an allylic substituent with acids or with triphenylcarbenium tetrafluoroborate. A variety of optically active tricarbonyliron complexes have been produced from these compounds. The optical purity of the product and the stereochemistry of the complexation reaction have been determined. The high efficiency of chirality transfer during complexation of 5,6-dimethoxy-substituted dienes makes this method suitable as a general route to resolved organoiron complexes. 相似文献
88.
89.
M.C. Cornock D.R. Robertson T.A. Stephenson C.L. Jones G.H.W. Milburn L. Sawyer 《Journal of organometallic chemistry》1977,135(2):C50-C52
The triphenylcyanoborate (N-bonded) complexes {η5-(C5Me5)Rh(SS)-NCBPh3} (SS? =?S2PMe2,?S2PPh2,?S2CNMe2), {η6-(C6H6)Ru(S2PPh2)-NCBPh3} and [Pd(S2 CNEt2)(PMe2Ph)(NCBPh3) have been synthesised and characterised by both spectroscopic and X-ray structural methods. 相似文献
90.
In this work, we demonstrate the potential use of immobilized pH gradient isoelectric focusing as a first dimension in shotgun proteomics. The high resolving power and resulting reduction in matrix ionization effects due to analyzing peptides with almost the exact same physiochemical properties, represents a significant improvement in performance over traditional strong cation-exchange first-dimensional analysis associated with the shotgun proteomics approach. For example, using this technology, we were able to identify more than 6000 peptides and > 1200 proteins from the cytosolic fraction of Escherichia coli from approximately 10 microg of material analyzed in the second-dimensional liquid chromatography-tandem mass spectrometry experiment. Sample loads on the order of 1 mg can be resolved to 0.25 isoelectric point (pI) units, which make it possible to analyze organisms with significantly larger genomes/proteomes. Accurate pI prediction can then be employed using currently available algorithms to very effectively filter data for peptide/protein identification, and thus lowering the false-positive rate for cross-correlation-based peptide identification algorithms. By simplifying the protein mixture problem to tryptic peptides, the effect of specific amino acids on pI prediction can be evaluated as a function of their position in the peptide chain. 相似文献