نتایج جستجو برای: regioselectivity

تعداد نتایج: 1520  

Journal: :Organic & biomolecular chemistry 2010
Matyas Tursky Linda L R Lorentz-Petersen Lasse B Olsen Robert Madsen

A straightforward and atom-economical method is described for the synthesis of 2,3-disubstituted indoles. Anilines and 1,2-diols are condensed under neat conditions with catalytic amounts of either [Cp*IrCl(2)](2)/MsOH or RuCl(3)·xH(2)O/phosphine (phosphine = PPh(3) or xantphos). The reaction does not require any stoichiometric additives and only produces water and dihydrogen as byproducts. Ani...

2012
Verena Resch Horst Lechner Joerg H Schrittwieser Silvia Wallner Karl Gruber Peter Macheroux Wolfgang Kroutil

Fluorine is commonly applied in pharmaceuticals to block the degradation of bioactive compounds at a specific site of the molecule. Blocking of the reaction center of the enzyme-catalyzed ring closure of 1,2,3,4-tetrahydrobenzylisoquinolines by a fluoro moiety allowed redirecting the berberine bridge enzyme (BBE)-catalyzed transformation of these compounds to give the formation of an alternativ...

2016
Sarah A. Shepherd Binuraj R. K. Menon Heidi Fisk Anna‐Winona Struck Colin Levy David Leys Jason Micklefield

Flavin-dependent halogenases are potentially useful biocatalysts for the regioselective halogenation of aromatic compounds. Haloaromatic compounds can be utilised in the synthesis and biosynthesis of pharmaceuticals and other valuable products. Here we report the first X-ray crystal structure of a tryptophan 6-halogenase (SttH), which enabled key residues that contribute to the regioselectivity...

Journal: :Journal of Pharmacy and Pharmacology 1976

Journal: :Chembiochem : a European journal of chemical biology 2014
Joshua N Kolev Jacqueline M Zaengle Rajesh Ravikumar Rudi Fasan

The development of effective strategies for modulating the reactivity and selectivity of cytochrome P450 enzymes represents a key step toward expediting the use of these biocatalysts for synthetic applications. We have investigated the potential of unnatural amino acid mutagenesis to aid efforts in this direction. Four unnatural amino acids with diverse aromatic side chains were incorporated at...

2017

t X-rayy crystal structures of a series of cationic (P-P)palladium(3,3-(CH3)2-C3H3) complexes (P-P = dppe (1,2bis(diphenylphosphino)ethane),, dppf (l,l'-bis(diphenylphosphino)ferrocene), DPEphos) and the (Xantphos)Pd(C3H5)BF44 complex have been determined. In the solid state structure, the phenyl rings of the ligandss are oriented in the direction of the non-symmetrically bound [3,3-(CH3)2-C3H3...

Journal: :Dalton transactions 2013
Dongmei Li Xiaoqin Huang Jianping Lin Chang-Guo Zhan

The fundamental reaction mechanism of cytochrome P450 2A6 (CYP2A6)-catalyzed N-methylhydroxylation of (S)-(-)-nicotine and the free energy profile have been studied by performing pseudobond first-principles quantum mechanical/molecular mechanical (QM/MM) reaction-coordinate calculations. In the CYP2A6-(S)-(-)-nicotine binding structures that allow for 5'-hydroxylation, the N-methyl group is als...

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