- Bromination of phenyl ether and other aromatics with bromoisobutyrate and dimethyl sulfoxide
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Bromoisobutyrate has been used for the first time as a general brominating source for the direct bromination of a diverse of simple phenyl ethers. Aromatic ethers bearing various substituents could be compatible in this reaction system delivering brominated arenes in moderate to good yields. The reaction system can also be expanded to bromination of phenols and unactivated arene. This process can be regarded as an alternative for the well-established bromination systems for bromoarene synthesis.
- Li, Jia-Qin,Chen, Xiao-Hui,Wang, Xian-Xun,Cui, Hai-Lei
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supporting information
(2021/09/09)
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- CXCR3 RECEPTOR AGONISTS
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Compounds are provided having the structure of the following Formula I: where R, R1, R2, R3a and R3b are as defined herein. Pharmaceutical compositions comprising such compounds, as well as methods related to their manufacture and use, are also provided.
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Paragraph 315
(2018/03/25)
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- Enantioselective total synthesis of (-)-walsucochin B
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The first enantioselective total synthesis of the structurally unique nortriterpenoid (-)-walsucochin B has been accomplished through the cationic polyolefin cyclization initiated by chiral epoxide. The core framework and the stereocenters in the natural
- Xu, Shiyan,Gu, Jixiang,Li, Huilin,Ma, Donghui,Xie, Xingang,She, Xuegong
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supporting information
p. 1996 - 1999
(2014/05/06)
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- Nickel-catalyzed decarbonylative polymerization of 5-alkynylphthalimides: A new methodology for the preparation of polyheterocycles
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A nickel-catalyzed decarbonylative cycloaddition was developed, in which 5-alkynylphthalimides reacted to afford a new type of polyisoquinolone. It was demonstrated for the first time that decarbonylative cycloaddition can be an elementary process of polycondensation for the preparation of heterocyclic polymers.
- Takeuchi, Makoto,Kurahashi, Takuya,Matsubara, Seijiro
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supporting information
p. 1566 - 1568
(2013/01/15)
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- Nuclear versus Side-Chain Bromination of Methyl-Substituted Anisoles by N-Bromosuccinimide
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The reactions of methyl-substituted anisoles with N-bromosuccinimide in CCl4 are reported.In the absence of a catalyst and under irradiation, some of these substrates undergo nuclear bromination in competition with the well-known side-chain bromination.With 2-methylanisole and with 2,6-dimethylanisole, nuclear bromination is not observed, whereas with 3,5-dimethylanisole, nuclear bromination at the 4-position is the dominating reaction.Investigation of the reactivity of several other methyl-substituted anisoles revealed the following general trend: methyl-substituted anisoles are attacked at the position para to the methoxy group rather than at the side chain when (at least) two methyl groups are present at positions 3 and 5.When positions 2 and 6 are both occupied, nuclear bromination is retarded; in 2,6-dimethylanisole and 2,3,6-trimethylanisole, only side-chain bromination is observed.In contrast, in 2,3,5,6-tetramethylanisole, the 4-position is sufficiently reactive to be brominated, because the decrease in reactivity by the presence of two methyl groups at positions 2 and 6 is overruled by the two additional methyl groups at positions 3 and 5; as a result, both nuclear and side-chain bromination occur.The observed chemospecificity can be rationalized by a difference in mechanism: the side-chain bromination is radical reaction, while the nuclear bromination is an electrophilic aromatic substitution reaction, which is so far contrary to expectation, as irradiation had been expected to favor radical processes.
- Gruter, Gert-Jan M.,Akkerman, Otto S.,Bickelhaupt, Friedrich
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p. 4473 - 4481
(2007/10/02)
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- Biphasic Electrophilic Halogenation of Activated Aromatics and Heteroaromatics with N-Halosuccinimides Catalyzed by Perchloric Acid
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Catalytic amounts of 70percent perchloric acid (0.1 - 10, mostly 0.1 - 1, mol percent, based on substrate) initiate the regioselective halogenation of activated aromatics and heteroaromatics with N-halosuccinimide (NXS, X = Cl or Br) in two-phase solid-liquid systems (NXS/hexane or NXS/CCl4) at room temperature to give ring-halogenated products in high yields.For example, thiophene is transformed to 2-halo or 2,5-dihalo derivatives (yield 82-98percent) using 1 or 2 equiv of NXS, respectively.Unsymmetrical 2,5-dihalothiophenes are obtained in 70-82percent yield by reacting 2-halothiophenes with an appropriate NXS.The reaction of 3-bromothiophene with NBS affords 2,3-dibromothiophene in 93-99percent yield. 1,3-Dimethoxybenzene and 2,3-dimethylanisole are halogenated regiospecifically at the 4-position to give the corresponding products in 81-94percent yield.
- Goldberg, Yuri,Alper, Howard
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p. 3072 - 3075
(2007/10/02)
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- THE SELECTIVE BENZYLIC BROMINATION OF o-XYLENES. A USEFUL SYNTHESIS OF PHTHALIDES
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The free radical bromination of aryl methyl groups can be controlled by the strategic positioning of a remote stereo-electronic blocking group on the aryl ring.This tactic leads to the efficient synthesis of selectively benzylically brominated molecules which are useful synthetic intermediates.This methodology has been applied to the synthesis of some phthalides.
- Box, Vernon, G. S.,Yiannikouros, George P.
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p. 1261 - 1270
(2007/10/02)
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- Synthesis of Tetrahydrobenzophenazines as Anthracyclinone N-Isosteres
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The anthracycline p-quinone unit has been replaced by a 1,4-di-N-oxide function in the first synthesis of a 7,9-dideoxyanthracyclinone hetero isostere. 4,11-Dimethoxy-9-(methoxycarbonyl)-7,8,9,10-tetrahydrobenzophenazine was synthesized and converted t
- Tracy, Michael,Acton, Edward M.
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p. 5116 - 5124
(2007/10/02)
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