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891.
A general approach to architecturally stimulating polycyclic structures is described by a concise, two-step procedure including a Ugi MCR (multicomponent reaction) and a subsequent Pictet-Spengler reaction starting from phenylethylamine-derived isocyanides. Ten compounds are described in full experimental detail, and yields range from medium to very good. Some of the reactions run with a high degree of stereoselectivity. The compound structures resemble steroid hormones and alkaloid classes of natural products. Exemplary products have been fully reduced to their tertiary amines. As such they could potentially become interesting biological probes. 相似文献
892.
Which, if any, hydrates will crystallise? Predicting hydrate formation of two dihydroxybenzoic acids
Braun DE Karamertzanis PG Price SL 《Chemical communications (Cambridge, England)》2011,47(19):5443-5445
A study of two dihydroxybenzoic acid isomers shows that computational methods can be used to predict hydrate formation, the compound:water ratio and hydrate crystal structures. The calculations also help identify a novel hydrate found in the solid form screening that validates this study. 相似文献
893.
Imidazolium ylides from a conjugate addition-proton transfer route and their cycloaddition reactions
Jones RC Iley JN Sanchis-Amat M Zhang X McKee V Coles SJ Gelbrich T 《Chemical communications (Cambridge, England)》2011,47(28):7965-7967
4,5-Dihydroimidazolium ylides formed by conjugate addition-proton transfer from dihydroimidazoles and doubly-activated electron-deficient alkenes afford 2:1 cycloadducts in a one-pot process wherein the alkene also acts as a dipolarophile. 相似文献
894.
Jeffery BJ Whitelaw EL Garcia-Vivo D Stewart JA Mahon MF Davidson MG Jones MD 《Chemical communications (Cambridge, England)》2011,47(45):12328-12330
In this paper we demonstrate the utility of Group 4 metals for the well-controlled and stereoselective (syndiotactic) ring opening polymerization (ROP) of rac-β-butyrolactone (BBL) and their ability to form copolymers. 相似文献
895.
Kwan P Schmitt D Volosin AM McIntosh CL Seo DK Jones AK 《Chemical communications (Cambridge, England)》2011,47(45):12367-12369
Stable immobilization of two redox proteins, cytochrome c and azurin, in a thin film of highly mesoporous antimony-doped tin oxide is demonstrated via UV-vis spectroscopic and electrochemical investigation. 相似文献
896.
Sharma SK May PS Jones MB Lense S Hardcastle KI MacBeth CE 《Chemical communications (Cambridge, England)》2011,47(6):1827-1829
The ligand bis(2-isobutyrylamidophenyl)amine has been prepared and used to stabilize both mononuclear and dinuclear cobalt(II) complexes. The nuclearity of the cobalt product is regulated by the deprotonation state of the ligand. Both complexes catalytically oxidize triphenylphosphine to triphenylphosphine oxide in the presence of O(2). 相似文献
897.
Pilgrim S Kociok-Köhn G Lloyd MD Lewis SE 《Chemical communications (Cambridge, England)》2011,47(16):4799-4801
Microbial 1,2-dihydroxylation of sodium benzoate permits the rapid construction of novel inositol-amino acid hybrid structures. Both β- and γ-amino acids are accessible by means of an acylnitroso Diels-Alder cycloaddition. 相似文献
898.
Thayer MP McGuire C Stennett EM Lockhart MK Canache D Novak M Schmidtke SJ 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,84(1):227-232
The local environment dictates the structural and functional properties of many important chemical and biological systems. The impact of pH on the photophysical properties of a series of para-aminobenzoic acids is examined using a combination of experimental spectroscopy and quantum chemical calculations. Following photoexcitation, PABA derivatives may undergo an intramolecular charge transfer (ICT) resulting in the formation of a zwitterionic species. The thermodynamics of the excited state reaction and temperature-dependence of the radiative emission processes are evaluated through variable temperature fluorescence spectroscopy carried out in a range of aqueous buffers. Quantum chemical calculations are used to analyze structural changes with modifications at the amine position and different protonation states. The ICT is only observed in the tertiary amine, which calculations show has more sp(2) character than the primary or secondary amines. Thermodynamic analysis indicates the ICT reaction is driven by entropy. 相似文献
899.
900.
Clifton LA Sanders MR Castelletto V Rogers SE Heenan RK Neylon C Frazier RA Green RJ 《Physical chemistry chemical physics : PCCP》2011,13(19):8881-8888
The self-assembly in solution of puroindoline-a (Pin-a), an amphiphilic lipid binding protein from common wheat, was investigated by small angle neutron scattering, dynamic light scattering and size exclusion chromatography. Pin-a was found to form monodisperse prolate ellipsoidal micelles with a major axial radius of 112 ± 4.5 ? and minor axial radius of 40.4 ± 0.18 ?. These protein micelles were formed by the spontaneous self-assembly of 38 Pin-a molecules in solution and were stable over a wide pH range (3.5-11) and at elevated temperatures (20-65 °C). Pin-a micelles could be disrupted upon addition of the non-ionic surfactant dodecyl-β-maltoside, suggesting that the protein self-assembly is driven by hydrophobic forces, consisting of intermolecular interactions between Trp residues located within a well-defined Trp-rich domain of Pin-a. 相似文献