- Concave reagents+. New 2′-substituted m-terphenyls
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New 2′-substituted 2,2″,6,6″-tetramethyl-1,1′: 3′,1″-terphenyls have been synthesized. Solubility of concave acids 4b-6b could be enhanced by substitution in 4 and 4″ position, allowing the study of hydrogen-bonded heterodimers. Concave acids show larger
- Abbass, Michael,Kuehl, Christine,Manthey, Christian,Mueller, Anja,Luening, Ulrich
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- Suppressing π-π Stacking interactions for enhanced solid-state emission of flat aromatic molecules: Via edge functionalization with picket-fence-type groups
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Polycyclic aromatic hydrocarbons (PAHs) are promising for materials science because of their high thermal and chemical stability, electron mobility, and unique photophysical properties. However, flat PAHs have limited applications owing to the low processability of their solutions, which originates from the strong π-π interaction between the aromatic rings. Herein, we report an effective method to suppress the π-π stacking of flat and large PAHs through steric hindrance. A 2,6-dimethylphenyl group, which is referred to as the picket-fence (PF) group based on its fence-like shape, was introduced on the edge of hexa-peri-hexabenzocoronene (HBC) through a bottom-up synthetic process. The PF group enhanced the solubility of HBC, while the unique photophysical properties of the core structure were preserved even in the solid state. The steric effect of the PF group is also demonstrated with other flat PAHs, which show excellent solid-state photophysical properties after functionalization with the PF group. Experimental and theoretical results indicate that the picket size plays a critical role in adjusting the PF effect. Furthermore, we fabricated the first organic light-emitting diode (OLED) that uses an HBC-based emitter, and the solid-state emission spectrum of the device is almost the same as that of the emitter in solution. This is possibly due to the maintenance of their morphology without aggregation due to the PF effect. Moreover, the full width at half maximum of the electroluminescence band was very narrow at only 20 nm. This journal is
- Cho, Hye Jin,Kim, Sang Won,Kim, Sungjin,Lee, Sangback,Lee, Juhyen,Cho, Yeonchoo,Lee, Yunmi,Lee, Tae-Woo,Shin, Hyeon-Jin,Song, Changsik
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- Photophysical properties of structural isomers of homoleptic Ir-complexes derived from xylenyl-substituted N-heterocyclic carbene ligands
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The phosphorescence properties of fac-Ir(pmp)3, mer-Ir(pmp)3, fac-Ir(dmpmp)3 and mer-Ir(dmpmp)3 (where pmp = 3-methyl-1-phenyl-2,3-dihydro-1H-imidazo[4,5-b]pyridine and dmpmp = 1-(2′,6′-dimethylbiphenyl-2-yl)-3-
- Yun, Bo-Sun,Kim, Jin-Hyoung,Kim, So-Yoen,Son, Ho-Jin,Cho, Dae Won,Kang, Sang Ook
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Read Online
- Aryl boronic acid preparation method
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The invention belongs to the technical field of fine chemical engineering, and relates to an aryl boronic acid preparation method. In the prior art, aryl boronic acid as a novel safe and environmentally-friendly arylation reagent is widely used in scientific research and production of various fine chemicals containing aryl structures in the fields of medicines, pesticides, advanced materials and the like; and the aryl boronic acid compound preparation method reported in the disclosed literature has problems of harsh reaction conditions and high cost. A purpose of the invention is to provide amethod, wherein an aryl boron compound is formed by carrying out a reaction on a Grignard reagent and trialkyl borate under mild conditions, the composition of the aryl boron compound is converted from the main component diaryl borate into the main component aryl borate, and the aryl borate is hydrolyzed to obtain aryl boric acid, so that the preparation cost of the acyl aryl boric acid compound can be remarkably reduced, and the method has good practical application prospect.
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Paragraph 0033-0036; 0040
(2020/01/25)
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- An efficient method for the hydrolysis of potassium organotrifluoroborates promoted by montmorillonite K10
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An efficient and non-expensive method for conversion of diverse potassium organotrifluoroborates to their corresponding boronic acids promoted by montmorillonite K10 using water as the reaction solvent is described. Further interconversion of potassium organotrifluoroborates to their corresponding boronic esters, via boronic acid intermediates was also successfully accomplished. The products were obtained in good yields, being the rate of hydrolysis influenced by the type of substituent present in the boronic acid.
- Silva, Renato L.,Santos, Cosme S.,Santos, Jonh A. M.,Oliveira, Roberta A.,Menezes, Paulo H.,Freitas, Juliano C. R.
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p. 1777 - 1785
(2018/09/04)
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- Development of a Concise Multikilogram Synthesis of LPA-1 Antagonist BMS-986020 via a Tandem Borylation-Suzuki Procedure
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The process development for the synthesis of BMS-986020 (1) via a palladium catalyzed tandem borylation/Suzuki reaction is described. Evaluation of conditions culminated in an efficient borylation procedure using tetrahydroxydiboron followed by a tandem Suzuki reaction employing the same commercially available palladium catalyst for both steps. This methodology addressed shortcomings of early synthetic routes and was ultimately used for the multikilogram scale synthesis of the active pharmaceutical ingredient 1. Further evaluation of the borylation reaction showed useful reactivity with a range of substituted aryl bromides and iodides as coupling partners. These findings represent a practical, efficient, mild, and scalable method for borylation.
- Smith, Michael J.,Lawler, Michael J.,Kopp, Nathaniel,McLeod, Douglas D.,Davulcu, Akin H.,Lin, Dong,Katipally, Kishta,Sfouggatakis, Chris
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p. 1859 - 1863
(2017/11/24)
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- Synthesis of substituted azulenes via Pt(II)-Catalyzed ring-expanding cycloisomerization
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Substituted azulenes, valuable structures for electronic devices and pharmaceuticals, have been synthesized by the platinum(II)-catalyzed intramolecular ring-expanding cycloisomerization of 1-en-3-yne with ortho-disubstituted benzene. This novel method provides an alternative route for the efficient synthesis of substituted azulenes. The reaction mechanism of selected catalytic transformations was explored using density functional calculations.
- Usui, Kazuteru,Tanoue, Kensuke,Yamamoto, Kosuke,Shimizu, Takashi,Suemune, Hiroshi
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p. 4662 - 4665
(2015/01/16)
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- Vaulted biaryls in catalysis: A structure-activity relationship guided tour of the immanent domain of the VANOL ligand
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The active site in the BOROX catalyst is a chiral polyborate anion (boroxinate) that is assembled in situ from three equivalents of B(OPh) 3 and one of the VANOL ligand by a molecule of substrate. The substrates are bound to the boroxinate by Hbonds to oxygen atoms O1-O3. The effects of introducing substituents at each position of the naphthalene core of the VANOL ligand are systematically investigated in an aziridination reaction. Substituents in the 4,4′- and 8,8′-positions have a negative effect on catalyst performance, whereas, substituents in the 7- and 7′-positions have the biggest impact in a positive direction. VANOL destination: The active site in the BOROX catalyst is a chiral polyborate anion (boroxinate; see figure) that is assembled in situ from three equivalents of B(OPh)3 and one of the VANOL ligand by a molecule of substrate. The effects of introducing substituents at each position of the naphthalene core of the VANOL ligand are systematically investigated in an aziridination reaction. Copyright
- Guan, Yong,Ding, Zhensheng,Wulff, William D.
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p. 15565 - 15571
(2013/11/19)
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- Robust acenaphthoimidazolylidene palladium complexes: Highly efficient catalysts for suzuki-miyaura couplings with sterically hindered substrates
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Robust acenaphthoimidazolylidene palladium complexes have been demonstrated as highly efficient and general catalysts for the sterically hindered Suzuki-Miyaura cross-coupling reactions in excellent yields even with low catalyst loadings under mild reaction conditions. The high catalytic activity of these complexes highlights that, besides the "flexible steric bulky" concept, σ-donor properties of the NHC ligands are also crucial to accelerate the transformations.
- Tu, Tao,Sun, Zheming,Fang, Weiwei,Xu, Mizhi,Zhou, Yunfei
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supporting information; experimental part
p. 4250 - 4253
(2012/10/07)
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- Scope of the palladium-catalyzed aryl borylation utilizing bis-boronic acid
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The Suzuki-Miyaura reaction has become one of the more useful tools for synthetic organic chemists. Until recently, there did not exist a direct way to make the most important component in the coupling reaction, namely the boronic acid. Current methods to make boronic acids often employ harsh or wasteful reagents to prepare boronic acid derivatives and require additional steps to afford the desired boronic acid. The scope of the previously reported palladium-catalyzed, direct boronic acid synthesis is unveiled, which includes a wide array of synthetically useful aryl electrophiles. It makes use of the newly available second generation Buchwald XPhos preformed palladium catalyst and bis-boronic acid. For ease of isolation and to preserve the often sensitive C-B bond, all boronic acids were readily converted to their more stable trifluoroborate counterparts.
- Molander, Gary A.,Trice, Sarah L. J.,Kennedy, Steven M.,Dreher, Spencer D.,Tudge, Matthew T.
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supporting information; experimental part
p. 11667 - 11673
(2012/09/05)
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- Palladium-catalyzed borylation of aryl and heteroaryl halides utilizing tetrakis(dimethylamino)diboron: One step greener
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The palladium-catalyzed borylation of aryl and heteroaryl halides with a novel borylating agent, tetrakis(dimethylamino)diboron [(Me2N) 2B-B(NMe2)2], is reported. The method is complementary to the previously reported method utilizing bis-boronic acid (BBA) in that certain substrates perform better under one set of optimized reaction conditions than the other. Because tetrakis(dimethylamino)diboron is the synthetic precursor to both BBA and bis(pinacolato)diboron (B 2Pin2), the new method represents a more atom-economical and efficient approach to current borylation methods.
- Molander, Gary A.,Trice, Sarah L. J.,Kennedy, Steven M.
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supporting information
p. 4814 - 4817,4
(2012/12/12)
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- Iron trichloride promoted hydrolysis of potassium organotrifluoroborates
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In the presence of iron trichloride, the hydrolysis of potassium organotrifluoroborates occurs smoothly at room temperature to afford the corresponding organoboronic acids in good to excellent yields. The hydrolysis is effective for aryltrifluoroborates as well as alkenyl- and alkyl- trifluoroborates.
- Blevins, David W.,Yao, Min-Liang,Yong, Li,Kabalka, George W.
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experimental part
p. 6534 - 6536
(2011/12/22)
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- Efficient hydrolysis of organotrifluoroborates via silica gel and water
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(Chemical Equation Presented) A general, mild, and efficient method for the hydrolysis of organotrifluoroborates to unveil boronic acids using silica gel and H2O was developed. This method proved to be tolerant of a broad range of aryl-, heteroaryl-, alkenyl-, and alkyltrifluoroborates as well as structurally diverse aminomethylated organotrifluoroborates.As anticipated, electron-rich substrates provided the corresponding boronic acids more readily than electron-poor substrates, owing to the resonance-stabilized difluoroborane intermediate. The method developed was expanded further for the conversion of organotrifluoroborates to the corresponding boronate esters. 2009 American Chemical Society.
- Molander, Gary A.,Cavalcanti, Livia N.,Canturk, Belgin,Pan, Po-Shen,Kennedy, Lauren E.
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supporting information; experimental part
p. 7364 - 7369
(2010/01/16)
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- Novel 3-aminochromans as potential pharmacological tools for the serotonin 5-HT7 receptor
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The synthesis of novel C6-aryl substituted derivatives of 3-(dimethylamino)chroman is described. The novel derivatives display 5-HT 7 receptor affinities that varies from nM to μM, indicating that this small set of derivatives constitute a nove
- Holmberg, Paer,Tedenborg, Lars,Rosqvist, Susanne,Johansson, Anette M.
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p. 747 - 750
(2007/10/03)
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- Dihydrobenzofuran and dihydrobenzothiophene 2,4-pentadienoic acid derivatives having selective activity for retinoid X (RXR) receptors
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Compounds of the formula where the variables have the meaning defined in the specification, are specific or selective agonists of RXR retinoid receptors.
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Page/Page column 29
(2010/01/31)
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- Imidazoquinoxaline protein tyrosine kinase inhibitors
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Novel imidazoquinoxalines and salts thereof, pharmaceutical compositions containing such compounds, and methods of using such compounds in the treatment of protein tyrosine kinase-associated disorders such as immunologic disorders.
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