38274-14-5Relevant academic research and scientific papers
Crystal structures and energy refinement of some 2,2'-disubstituted biphenyl compounds
Benmenni, L.,Alilou, E. H.,Giorgi, M.,Pierrot, M.,Reglier, M.
, p. 345 - 352 (1994)
Synthesis and structural determination by X-ray crystallography of three substituted biphenyl structures are reported: (2) is monoclinic P21/n with a = 10.805(4), b = 8.079(3), c = 16.232(6) Angstroem, β = 100.96(5) deg; (4) is monoclinic P21/n with a = 9.966(3), b = 10.007(3), c = 13.053(4) Angstroem, β = 96.74(5) deg; (5) is triclinic P with a = 12.033(5), b = 16.903(8), c = 9.752(4) Angstroem, α = 94.70(3) deg, β = 112.56(3) deg, γ = 76.12(3) deg.In all compounds the biphenyl has two identical substituents in an ortho position to the center inter-ring bond and present variable inter-ring twist angles.In the process of investigating molecular geometry, we are interested in studying whether the calculated conformations of our molecules can fit the crystallographic structures.
2,2′-Bis(methylene)biphenylidene-bridged bis(3-indenyl) dichloride complexes of Ti, Zr and Hf as catalyst precursors for ethylene polymerization
Abdelbagi, Mohamed E.M.,Mondal, Swastik,van Smaalen, Sander,Alt, Helmut G.
, p. 176 - 186 (2018)
ansa metallocene complexes of Ti, Zr and Hf were synthesized, characterized and tested as catalysts for homogeneous ethylene polymerization. The ligand system comprises two indenyl moieties tethered at the 1,1′-positions via a 2,2′-dimethyl biphenylene bridge. The ligand precursor was obtained by the reduction of diphenic acid using lithium aluminum hydride (LiAlH4), followed by the reaction with phosphorus tribromide, and, finally, the reaction with indenyllithium. The corresponding group (IV) metal complexes were synthesized by deprotonation of the ligand precursors using n-BuLi followed by reactions of the corresponding metal tetrachloride. After activation with methylaluminoxane (MAO), the zirconium and hafnium complexes proved as highly active catalysts for ethylene polymerization. The zirconium complex 6 showed the best performance with 12,460 kg PE/mol cat. h. The titanium complex 5 showed no catalytic activity obviously because of decomposition reactions.
Cu-catalyzed enantioselective alkylarylation of vinylarenes enabled by chiral binaphthyl-box hybrid ligands
Sakurai, Shunya,Matsumoto, Akira,Kano, Taichi,Maruoka, Keiji
, p. 19017 - 19022 (2020/11/02)
Transition-metal-catalyzed radical relay coupling reactions have recently emerged as one of the most powerful methods to achieve difunctionalization of olefins. However, there has been limited success in applying this method to asymmetric catalysis using an effective chiral ligand. Herein we report the Cu-catalyzed enantioselective alkylarylation of vinylarenes using alkylsilyl peroxides as alkyl radical sources. This reaction proceeds under practical reaction conditions and affords chiral 1,1-diarylalkane structures that are found in a variety of bioactive molecules. Notably, a highly enantioselective reaction was accomplished by combining chiral bis(oxazoline) ligands with chiral binaphthyl scaffolds.
Gold(I) Complexes Stabilized by Nine- and Ten-Membered N-Heterocyclic Carbene Ligands
Cervantes-Reyes, Alejandro,Rominger, Frank,Rudolph, Matthias,Hashmi, A. Stephen K.
, p. 11745 - 11757 (2019/08/20)
Nine- and ten-membered N-heterocyclic carbene (NHC) ligands have been developed and for the first time their gold(I) complexes were synthesized. The protonated NHC pro-ligands 2 a–h were prepared by the reaction of readily available N,N′-diarylformamidines with bis-electrophilic building blocks, followed by anion exchange. In situ deprotonation of the tetrafluoroborates 2 a–h with tBuOK in the presence of AuCl(SMe2) provided fast access to NHC-gold(I) complexes 3–10. These new NHC-gold(I) complexes show very good catalytic activity in a cycloisomerization reaction (0.1 mol % catalyst loading, up to 100 % conversion) and their solid-state structures reveal high steric hindrance around the metal atom (%Vbur up to 53.0) which is caused by their expanded-ring architecture.
1-Aminobenzocyclobutene-1-phosphonic Acid and Related Compounds as Inhibitors of Phenylalanine Ammonia-Lyase
Zoń, Jerzy,Miziak, Piotr
, (2017/05/17)
Five new geminal aminocycloalkanephosphonic acids (4 – 8) containing both an aromatic ring and a cycloalkane ring were synthesized and evaluated as potential inhibitors of buckwheat phenylalanine ammonia-lyase (PAL). Within the set of compounds which are related to 2-aminoindane-2-phosphonic acid (AIP, 3), a known powerful inhibitor of PAL, racemic 1-aminobenzocyclobutene-1-phosphonic acid (4), was six times weaker than AIP as an in vitro inhibitor of buckwheat PAL, but six times stronger than AIP as an in vivo inhibitor of phenylalanine-derived anthocyanin synthesis in buckwheat.
A Binaphthyl-Based Scaffold for a Chiral Dirhodium(II) Biscarboxylate Ligand with α-Quaternary Carbon Centers
Chen, Po-An,Setthakarn, Krit,May, Jeremy A.
, p. 6155 - 6161 (2017/09/15)
A chiral dirhodium(II) paddlewheel complex has been synthesized from biscarboxylate ligands derived from BINOL, and the resulting complex has been used in enantioselective carbene/alkyne cascade reactions. The ligand design was guided by requirements of α
Synthesis of biphenyl-based ligand: Application in copper-mediated chemoselective michael reaction
Sundar, M. Shyam,Bedekar, Ashutosh V.
, p. 3582 - 3593 (2015/08/11)
A biphenyl-based ligand attached was synthesized and screened in copper-mediated Michael reaction. The catalyst system works well with carbon or sulfur nucleophiles as Michael donors and cyclohexenone or chalcones as the acceptors under mild and neutral r
Design, synthesis and in vitro evaluation of novel bivalent S-adenosylmethionine analogues
Joce, Catherine,White, Rebecca,Stockley, Peter G.,Warriner, Stuart,Turnbull, W. Bruce,Nelson, Adam
supporting information; experimental part, p. 278 - 284 (2012/03/11)
In optimal cases, bivalent ligands can bind with exceptionally high affinity to their protein targets. However, designing optimised linkers, that orient the two binding groups perfectly, is challenging, and yet crucial in both fragment-based ligand design
Highly enantioselective aldol reactions using a tropos dibenz[c,e]azepine organocatalyst
Lygo, Barry,Davison, Christopher,Evans, Timothy,Gilks, James A.R.,Leonard, John,Roy, Claude-Eric
experimental part, p. 10164 - 10170 (2012/01/03)
The four-step synthesis of a chiral primary tertiary diamine salt, possessing a tropos dibenz[c,e]azepine ring is described. It is shown that 3.5-5 mol % of this salt is capable of promoting highly enantioselective crossed-aldol reactions between cyclohexanone and a series of aromatic aldehydes. In all cases, the aldol reactions proceed with high diastereoselectivity for the anti-aldol product. The outcome of crossed-aldol reactions involving other cyclic ketones and acyclic ketones are also described. All examples involving cyclic ketones result in selectivity for the anti-aldol products, whereas acyclic ketones were found to favour the syn-aldol products. A discussion on the role of the chiral primary tertiary diamine salt in the catalysis of the aldol reactions is also presented.
Flow-vacuum pyrolysis of dibenzocycloheptane annelated derivative on zeolites catalysts
Istrati, Daniela,Parvulescu, Luminitza,Popescu, Angela,Mihaiescu, Dan,Andrei, Elena,Badea, Florin
, p. 847 - 850 (2011/06/21)
The pyrolysis of 5H-6,7-dihydrodibenzo[a,c]cyclohepten-6-ol (5) in FVP conditions, a method of thermal decomposition in advanced vacuum, inert atmosphere on zeolites/acid Al2O3 at variable temperature between 300- 350° C is presented. The reaction products were identified by GC/MS using authentic samples and a reaction mechanism involving cationic species as intermediates was proposed. A comparison with the pyrolysis of the same compound performed in FVP conditions on quartz is presented.
