718-24-1Relevant articles and documents
A new insight into the push-pull effect of substituents via the stilbene-like model compounds
Cao, Chaotun,Cao, Chenzhong,Zeng, Zhao
, (2022/02/01)
In this paper, authors report on 1-pyridyl-2-arylethenes, 1-furyl-2-arylethylenes, 1,2-diphenylpropylenes and substituted cinnamyl anilines as stilbene-like model compounds to investigate the factors dominating the push-pull effect of substituents via usi
Determination and application of the excited-state substituent constants of pyridyl and substituted phenyl groups
Cao, Chao-Tun,Yan, Lu,Cao, Chenzhong
supporting information, (2021/05/21)
Thirty six 1-pyridyl-2-arylethenes XCH=CHArY (abbreviated XAEY) were synthesized, in which, X is 2-pyridyl, 3-pyridyl and 4-pyridyl and Y is OMe, Me, H, Br, Cl, F, CF3, and CN. Their ultraviolet absorption spectra were measured in anhydrous ethanol, and their wavelengths of absorption maximum λmax were recorded. Also, the 234 λmax values of 1-substituted phenyl-2-arylethylene compounds (XAEY, where X is substituted phenyl) were collected. The excited-state substituent constants (Formula presented.) of three pyridyl groups and 23 substituted phenyl groups (total of 26) were obtained by means of curve-fitting method. Taking the λmax values of 358 samples of bi-arylethene derivatives as a data set and 126 samples of bi-aryl Schiff bases (including nine compounds synthesized by this work) as another data set, quantitative correlation analyses were performed by employing the obtained (Formula presented.) as a parameter, and good results were obtained for the two data sets. The reliability of the obtained (Formula presented.) values was verified. The results of this paper can provide excited-state substituent constants for the study and application of optical properties of conjugated organic compounds containing aryl groups.
Br?nsted acid-catalysed conjugate addition of photochemically generated α-amino radicals to alkenylpyridines
Hepburn, Hamish B.,Melchiorre, Paolo
, p. 3520 - 3523 (2016/03/04)
The conjugate addition of α-amino radicals to alkenylpyridines has been accomplished by the synergistic merger of Br?nsted acid and visible light photoredox catalysis. Key to reaction development was the protonation of the alkenylpyridines that transientl
(E)-Specific direct Julia-olefination of aryl alcohols without extra reducing agents promoted by bases
Yao, Chuan-Zhi,Li, Qiang-Qiang,Wang, Mei-Mei,Ning, Xiao-Shan,Kang, Yan-Biao
supporting information, p. 7729 - 7732 (2015/05/12)
An unprecedented base-promoted direct olefination of aryl alcohols with sulfones via a Julia-type reaction has been described. No extra reductants are needed for Julia reaction since alcohols work as double sources of aldehydes and the hydride. Generally high yields were given for both terminal and highly (E)-selective internal olefins.
Bulky monodentate biphenylarsine ligands: Synthesis and evaluation of their structure effects in the palladium-catalyzed Heck reaction
Quinteros, Gisela J.,Uberman, Paula M.,Martín, Sandra E.
supporting information, p. 2698 - 2705 (2015/04/27)
Biphenyl-based arsine ligands were prepared in two-step fashion by Pd-catalyzed arsination and microwave-assisted Suzuki-Miyaura coupling, providing sterically demanding arsine ligands in overall isolated yields up to 82 % as air-stable solids. Short reaction times were achieved with the assistance of microwave irradiation in the direct and simple described protocol for the synthesis of biarylarsine ligands. The activities of the biphenyl arsine ligands were explored in Pd-catalyzed Heck coupling. As a general trend, the ligands with "blocked" ortho-positions on the non-arsine-containing ring of the biphenyl backbone performed more efficiently in the coupling reaction. This catalytic system allowed several interesting stilbenes to be obtained in very good yields. Sterically demanding biphenyl-based arsine ligands were prepared in high overall yields by microwave-assisted Suzuki-Miyaura coupling. The ligands were evaluated in the Pd-catalyzed Heck coupling reaction; the most active were those with "blocked" ortho-positions on the non-arsine-containing ring of the biphenyl backbone.
Synthesis of [N,P] ligands based on pyrrole. Application to the total synthesis of arnottin i
Suárez-Meneses, Jesús V.,Bonilla-Reyes, Edgar,Blé-González, Ever A.,Ortega-Alfaro, M. Carmen,Toscano, Rubén Alfredo,Cordero-Vargas, Alejandro,López-Cortés, José G.
supporting information, p. 1422 - 1430 (2014/02/14)
This paper describes the synthesis of a new class of [N,P] ligands based on pyrrole with a dimethylamino group as hard donor and a phosphine moiety as soft base. We have also modified the phosphine fragment to change the electronic and steric properties of these ligands. Palladium complex 3a proved to be very efficient in Heck cross-coupling reactions and in intramolecular aryl-aryl couplings of esters and amides. We have demonstrated the applicability and efficiency of this novel catalyst in the total synthesis of the natural product arnottin I.
A [2+2] cross-photodimerisation of photostable olefins via a three-component cocrystal solid solution
Buar, Dejan-Kreimir,Sen, Arundhuti,Mariappan, S. V. Santhana,MacGillivray, Leonard R.
supporting information; experimental part, p. 1790 - 1792 (2012/03/09)
A ditopic hydrogen-bond-donor template in the form of resorcinol facilitates a [2+2] cross-photodimerisation of 4-Cl-stilbazole and 4-Me-stilbazole in a rare cocrystal solid solution. A photoreaction does not proceed with the olefins individually or as a solid solution composed solely of the two olefins.
Ligand-free palladium-catalysed oxidative Heck reaction of 4-vinylpyridine with arylboronic acids: Selective synthesis of (E)-4-styrylpyridines
Shi, Chuanli,Ding, Jinchang,Jiang, Jun,Chen, Jiuxi,Wu, Huayue,Liu, Miaochang
supporting information; experimental part, p. 322 - 325 (2012/09/21)
A ligand-free palladium-catalysed oxidative Heck reaction of various arylboronic acids with 4-vinylpyridine has been developed, achieving (E)-4-styrylpyridines with high selectively in moderate to good yields. A plausible mechanism for the formation of (E)-4-styrylpyridines has been proposed.
Kinetics of Reaction of Phenacyl Bromide with 3- and 4-Substituted Pyridines and 4-Substituted 4-Styrylpyridines
Shunmugasundaram, A.,Balakumar, S.
, p. 775 - 777 (2007/10/02)
The rates of reaction of phenacyl bromide with 3- and 4-substituted pyridines and 4'-substituted 4-styrylpyridines have been measured in aq. acetone (90percent, v/v) at 30 deg C, 35 deg C and 40 deg C and the activation parameters have been evaluated.Satisfactory Hammett correlations are obtained for both pyridine and styrylpyridine series.The effectiveness of transmission of substituent effect in styrylpyridine system relative to pyridine system in this reaction is calculated to be 0.104.From the Bronsted relationship the coefficient (βN) is found to be 0.48, indicating that the extent of bond formation in the transition state is moderate.
Anil-Synthese. 22 Mitteilung. Ueber die Herstellung von Styryl und Distyryl-Derivaten des Pyridins
Siegrist, Adolf Emil,Meyer, Hans Rudolf,Gassmann, Peter,Moss, Serge
, p. 1311 - 1334 (2007/10/02)
2,4-, 2,5- and 2,6-Dimethylpyridines react with anils of aromatic aldehydes in the presence of dimethylformamide and potassium hydroxide to yield the corresponding distyrylpyridines ('anil synthesis').Under the same reaction conditions (4-methylstyryl)pyridines are converted to (stilbenylvinyl)pyridines.Similarly, the Schiff's base derived from pyridine-3-carbaldehyde and chloranile on treatment with methyl- and p-tolyl-substituted aromatic hetericycles gives the corresponding (heteroaryl-styryl)pyridines, whereas with the Schiff's bases derived from pyridine-2= and -4-carbaldehyde side reactions, such as dimerization followed by disproportionation predominate.
