25624-52-6Relevant articles and documents
Multi-layer 3D chirality: new synthesis, AIE and computational studies
Liu, Yangxue,Wu, Guanzhao,Yang, Zhen,Rouh, Hossein,Katakam, Nandakumar,Ahmed, Sultan,Unruh, Daniel,Cui, Zhonghua,Lischka, Hans,Li, Guigen
, p. 692 - 698 (2020)
New synthesis of multi-layer 3D chiral molecules has been developed under novel conditions to give better outcomes. The aggregation-induced emission (AIE), UV irradiation/excitation, charge transfer (CT) and local excited (LE) ππ* transitions have been investigated on a representative individual enantiomer of pseudo C2 asymmetry which was made possibly by differentiating moieties on phosphorous on N-phosphonyl ring of chiral sandwich framework. Meanwhile, a new tandem C-N/C-C coupling reaction was unexpectedly rendered providing a novel access to special benzo[a]carbazoles.
Modeling biologically important NH π interactions using peri-disubstituted naphthalenes
Dyablo, Olga V.,Dzhangiryan, Narek A.,Filarowski, Aleksander,Ozeryanskii, Valery A.,Pogosova, Olga G.,Pozharskii, Alexander F.,Vasilikhina, Kseniya M.
, p. 12468 - 12481 (2020)
For the first time, systematic studies of 8-aryl and 8-pyrrolyl derivatives of 1-aminonaphthalene as simple, synthetically available, and nicely preorganized models were conducted for a better understanding the properties of NH π interactions involved in the stabilization of the secondary and tertiary protein structures as well as the recognition of guest molecules by biological receptors. It was shown that the NH π binding is especially effective when the NH-donor is a positively charged group, for example, Me2NH+, and the π-donor is an electron-rich aromatic substituent, in particular, the 1-pyrrolyl or the 4- hydroxyphenyl group. Using protonated tetrafluoroborate salts, a strong counterion effect was demonstrated by means of theoretical calculations. Through several mechanisms, including short CH F contacts, bifurcation, and long-range dispersion, the counterion promotes considerable structural changes and weakens the NH π interactions from 12-15 kcal mol-1 in "naked"cations to 5-9 kcal mol-1 in the salts. To this end, 8-(2,5-dimethylpyrrol-1-yl)-N,N-dimethylnaphthalene-1-ammonium tetrafluoroborate, with the record linearity and shortness (2.07 ?) of the NH π-centroid bond, was recognized as the most appropriate model with the strongest NH π interaction ever described.
Planar chiral flavinium salts: Synthesis and evaluation of the effect of substituents on the catalytic efficiency in enantioselective sulfoxidation reactions
Jurok, Radek,Hodacova, Jana,Eigner, Vaclav,Dvorakova, Hana,Setnicka, Vladimir,Cibulka, Radek
supporting information, p. 7724 - 7738 (2013/12/04)
A series of substituted planar chiral flavinium salts with a phenyl "cap" have been prepared as potential catalysts for enantioselective sulfoxidation reactions with hydrogen peroxide by using an approach based on the synthesis of (arylamino)uracils and their condensation with substituted nitrosobenzenes. The effect of substituents at various positions on the ability of the catalyst to promote enantioselective sulfoxidation recations was investigated. Introduction of the tyrosine group into the side-chain of the flavinium species or substitution of the nitrogen N-3 of the flavin unit by o-isopropylphenyl has a remarkably positive effect on the enantioselectivity of the sulfoxidation reactions of aromatic and aliphatic substrates, respectively. On the other hand, substitution of the phenyl "cap" led to a substantial decrease in the efficiency of the catalyst. In summary, optimisation of the structures of the planar chiral flavinium catalysts led to enantioselectivities of up to 61 % ee for aromatic sulfides and of up to 65 % ee for tert-butyl methyl sulfide. By making structural changes to the planar chiral flavinium catalysts, the enantioselectivities of the sulfoxidation of aryl methyl sulfides and tert-butyl methyl sulfide with hydrogen peroxide have been improved. Copyright
