- Diarylamines with the Neighboring Pyridyl Group: Synthesis and Modulation of the Amine Functionality via Intramolecular H-Bonding
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New pyridyl-containing diarylamines were obtained via Cuassisted reductive amination of the ortho-2-pyridylarylboronic acids. Comparative analysis of the spectral and electrochemical data obtained for new diarylamines and their pyridyl-free counterparts revealed the intramolecular H-bond (IMHB) formation which significantly influences the properties of the amino group. The electron density at the N atom of the amino group is increased due to partial weakening of the N-H bond, although the BDE and activation energy for the H-atom abstraction is increased due to the chelating effect of two N atoms. The orthopyridyl-containing diarylamines are more prone to be oxidized as compared to their pyridyl-free counterparts; the shift in the oxidation potential values correlates with the strength of the intramolecular Hbonding which can be tuned by inserting substituents in the pyridyl or phenyl rings. The IMHB is reserved even in polar solvents having a significant H-acceptor ability (such as DMSO) but can be destroyed in methanol, testifying in favor of the dynamic nature of the H-bonding.
- Grishin, Yuri K.,Klimchuk, Ivan A.,Levitskiy, Oleg A.,Magdesieva, Tatiana V.,Roznyatovsky, Vitaly A.,Tarasevich, Boris N.
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- Simultaneous expansion of 9,10 boron-doped anthracene in longitudinal and lateral directions
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Doubly boron-doped anthracenes and pentacenes have been longitudinally and laterally expanded through annulation of thiophene or benzene rings. The obtained series of closely related compounds allowed an assessment of key structure-property relationships with a focus on optoelectronic characteristics. Most of the products are benchtop-stable blue emitters and capable of accepting two electrons in a reversible manner. The syntheses involved late-stage modifications through photocyclization or stepwise oxidative C-C coupling (DDQ/BF3·Et2O) as well as cyclocondensation of ortho-disilylated or -diborylated aryl building blocks.
- John, Alexandra,Kirschner, Sven,Fengel, Melina K.,Bolte, Michael,Lerner, Hans-Wolfram,Wagner, Matthias
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supporting information
p. 1871 - 1877
(2019/02/28)
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- Access to "friedel-Crafts-Restricted" tert -alkyl aromatics by activation/methylation of tertiary benzylic alcohols
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Herein we describe a two-step protocol to prepare m-tert-alkylbenzenes. The appropriate tertiary benzylic alcohols are activated with SOCl2 or concentrated HCl and then treated with trimethylaluminum, affording the desired products in 68-97% yields (22 examples). This reaction sequence is successful in the presence of a variety of functional groups, including acid-sensitive and Lewis-basic groups. In addition to t-Bu groups, 1,1-dimethylpropyl and 1-ethyl-1-methylpropyl groups can also be installed using this method.
- Hartsel, Joshua A.,Craft, Derek T.,Chen, Qiao-Hong,Ma, Ming,Carlier, Paul R.
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experimental part
p. 3127 - 3133
(2012/05/20)
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- Quinoline synthesis: Scope and regiochemistry of photocyclisation of substituted benzylidenecyclopentanone O-alkyl and O-acetyloximes
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Irradiation of substituted 2-benzylidenecyclopentanone O-alkyl and O-acetyloximes in methanol provides a convenient synthesis of alkyl, alkoxy, hydroxy, acetoxy, amino, dimethylamino and benzo substituted annulated quinolines. para-Substituents yield 6-substituted-2,3-dihydro-1H-cyclopenta[b] quinolines with 8-substituted products being obtained from ortho-substituted starting materials. Reactions of meta-substituted precursors are highly regioselective, with alkyl substituents leading to 5-substituted 2,3-dihydro-1H-cyclopenta[b]quinolines and more strongly electron-donating substituents generally resulting in 7-substituted products. 2-Furylmethylene and 2-thienylmethylene analogues yield annulated furo- and thieno-[2,3e]pyridines respectively. Sequential E- to Z-benzylidene group isomerisation and six π-electron cyclisation steps result in formation of a short-lived dihydroquinoline intermediate which spontaneously aromatises by elimination of an alcohol or acetic acid. For 2-benzylidenecyclopentanone O-allyloxime, singlet excited states are involved in both steps. The Royal Society of Chemistry 2007.
- Austin, Mark,Egan, Oliver J.,Tully, Raymond,Pratt, Albert C.
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p. 3778 - 3786
(2008/10/09)
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- Efficient new approach for the synthesis of N,N-dialkylamino-1,2,4-triazoles
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A series of 3-NN-dialkylamino-4,5-diaryl-1,2,4-triazoles were synthesized in high yield under mild reaction conditions by coupling functionalized arylmagnesiums with isothiocyanates and cyclization with Viehe's salts. No selective thionation reaction was
- Zhang, Qiang,Peng, Youyi,Welsh, William J.
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p. 2635 - 2645
(2008/02/04)
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- 2,5-Di-tert-butylphenylsilanetriol: Synthesis and reactivity
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Stable 2,5-di-tert-butylphenylsilanetriol was prepared by a stepwise synthesis. This compound reacted with triethylenediamine and lanthanum silylamide to form a 1 : 1 molecular complex and highly thermally stable lanthanosilsesquioxane, respectively.
- Kornev,Chesnokova,Zhezlova,Kurskii,Makarenko
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p. 1563 - 1567
(2007/10/03)
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- Alkyl, alkoxy and thioalkoxy substituted diphenyl acetylenes having retinoid like activity
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Retinoid like activity is exhibited by compounds of the formula STR1 where R1 -R4 independently are hydrogen, lower alkyl, cycloalkyl or lower alkenyl, A and B independently are hydrogen, lower alkyl cycloalkyl, lower alkenyl, SR* or
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- Acetylenes disubstituted with a pyridinyl group and a substituted phenyl group having retinoid like activity
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Retinold like activity is exhibited by compounds of the formula STR1 where R1 -R3 independently are hydrogen, lower alkyl, cycloalkyl or lower alkenyl, A and B independently are hydrogen, lower alkyl, cycloalkyl, lower alkenyl, SRsu
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- Photochemical Bromination of Simple Arenes
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Photochemical bromination of benzene, fluorobenzene, chlorobenzene, t-butylbenzene, α,α,α-trifluorotoluene, and (in tetrachloromethane) biphenyl and naphthalene gives substitution products and adducts such as 1,2,3,4,5,6-hexabromocyclohexane (1).The decomposition of (1) and of the analogous chlorobenzene adduct (3) under photochemical conditions gives the parent arene, the monobrominated halogenobenzene, and bromine which may be scavenged by toluene to give benzyl bromide or by benzene to give bromobenzene and dibromobenzenes.Addition is a kinetically controlled process, so that the mechanism of formation of these aryl bromides must be largely through the reversible formation of these adducts.This is consistent with the unusual orientation of apparent attack by bromine upon the arene substrates, since the relative amounts of the isomeric aryl bromides is a consequence of the relative stabilities and ease of elimination of HBr and Br2 from a family of adducts. The range of isomer distribution found within the reaction of each arene with bromine is consistent with two competing processes involved in the formation of the aryl bromides; one of these might by the direct homolytic substitution by bromine atoms upon the arene.
- Bolton, Roger,Bhangar, Muhammad Iqbal,Williams, Gareth H.
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p. 893 - 896
(2007/10/02)
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