- Enantioselective Synthesis of Cyclopropanone Equivalents and Application to the Formation of Chiral β-Lactams
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Cyclopropanone derivatives have long been considered unsustainable synthetic intermediates because of their extreme strain and kinetic instability. Reported here is the enantioselective synthesis of 1-sulfonylcyclopropanols, as stable yet powerful equivalents of the corresponding cyclopropanone derivatives, by α-hydroxylation of sulfonylcyclopropanes using a bis(silyl) peroxide as the electrophilic oxygen source. This work constitutes the first general approach to enantioenriched cyclopropanone derivatives. Both the electronic and steric nature of the sulfonyl moiety, which serves as a base-labile protecting group and confers crystallinity to these cyclopropanone precursors, were found to have a crucial impact on the rate of equilibration to the corresponding cyclopropanone. The utility of these cyclopropanone surrogates is demonstrated in a mild and stereospecific formal [3+1] cycloaddition with simple hydroxylamines, leading to the efficient formation of chiral β-lactam derivatives.
- Jang, Yujin,Johnson, J. Drake,Jung, Myunggi,Lindsay, Vincent N. G.,Poteat, Christopher M.,Williams, Rachel G.
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supporting information
p. 18655 - 18661
(2020/08/21)
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- Synthesis of new tricyclic 5,6-dihydro-4H-benzo[b][1,2,4]tri-azolo[1,5-d][1,4]diazepine derivatives by [3+ + 2]-cyclo-addition/rearrangement reactions
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Two new series of tricyclic heterocycles, namely 5,6-dihydro-4H-benzo[b][1,2,4]triazolo[1,5-d][1,4]diazepinium salts 10 and the related neutral, free bases 13 were synthesized from 4-acetoxy-1-acetyl-4-phenylazo-1,2,3,4-tetrahydroquinolines 8 and nitriles 9 in the presence of aluminium chloride by the [3+ + 2]-cycloaddition reaction of the in situ generated azocarbenium intermediates 14 followed by a ring-expansion rearrangement. In the rearrangement reaction, the phenyl substituent in the initially formed spiro-triazolium adducts 16 underwent a [1,2]-migration from C(3) to the electron-deficient N(2). This led to the ring expansion from 6-membered piperidine to 7-membered diazepine furnishing the tricyclic 1,2,4-triazole-fused 1,4-benzodiazepines.
- Luan, Lin-bo,Song, Zi-jie,Li, Zhi-ming,Wang, Quan-rui
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p. 1826 - 1833
(2018/08/21)
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- Efficient and Mild Ullmann-Type N-Arylation of Amides, Carbamates, and Azoles in Water
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A simple, sustainable, efficient, mild, and low-cost protocol was developed for d-glucose-assisted Cu-catalyzed Ullmann reactions in water for amides, carbamates, and nitrogen-containing heterocycles. The reaction was compatible with diverse aryl/heteroaryl iodides, giving highly substituted pyridine, indole, or indazole rings. This method offers an attractive alternative to existing protocols, because the reaction proceeds in aqueous media, occurs at or near ambient temperature, and provides the N-arylated products in good to high yields.
- Bollenbach, Maud,Aquino, Pedro G. V.,de Araújo-Júnior, Jo?o Xavier,Bourguignon, Jean-Jacques,Bihel, Frédéric,Salomé, Christophe,Wagner, Patrick,Schmitt, Martine
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supporting information
p. 13676 - 13683
(2017/10/10)
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- Formation of acridones by ethylene extrusion in the reaction of arynes with β-lactams and dihydroquinolinones
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N-Unsubstituted β-lactams react with a molecule of aryne by insertion into the amide bond to form a 2,3-dihydroquinolin-4-one, which subsequently reacts with another molecule of aryne to form an acridone by extrusion of a molecule of ethylene. 2,3-Dihydroquinolin-4-ones react under the same reaction conditions to afford identical results. This is the first example of ethylene extrusion in aryne chemistry.
- Fang, Yuesi,Rogness, Donald C.,Larock, Richard C.,Shi, Feng
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p. 6262 - 6270
(2012/09/22)
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- Synthesis of 2,3-dihydro-4(1H)-quinolones and the corresponding 4(1H)-quinolones via low-temperature fries rearrangement of N-arylazetidin-2- ones
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N-Arylazetidin-2-ones of the general form 1, which are readily prepared by GoldbergBuchwald-type copper-catalyzed coupling of N-unsubstituted azetidin-2-ones with the relevant aryl halide or using Mitsunobu cyclization processes, undergo smooth Fries-rearrangement in triflic acid at 018°C to give the isomeric 2,3-dihydro-4(1H)-quinolones (2). Dehydrogenation of the latter compounds using 10% Pd on C in 1.0M aqueous sodium hydroxide/propan-2-ol mixtures at ca. 82°C provides the corresponding 4(1H)-quinolones (3).
- Lange, Jens,Bissember, Alex C.,Banwell, Martin G.,Cade, Ian A.
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experimental part
p. 454 - 470
(2011/10/09)
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- Chroman and tetrahydroquinoline ureas as potent TRPV1 antagonists
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Novel chroman and tetrahydroquinoline ureas were synthesized and evaluated for their activity as TRPV1 antagonists. It was found that aryl substituents on the 7- or 8-position of both bicyclic scaffolds imparted the best in vitro potency at TRPV1. The most potent chroman ureas were assessed in chronic and acute pain models, and compounds with the ability to cross the blood-brain barrier were shown to be highly efficacious. The tetrahydroquinoline ureas were found to be potent CYP3A4 inhibitors, but replacement of bulky substituents at the nitrogen atom of the tetrahydroisoquinoline moiety with small groups such as methyl can minimize the inhibition.
- Schmidt, Robert G.,Bayburt, Erol K.,Latshaw, Steven P.,Koenig, John R.,Daanen, Jerome F.,McDonald, Heath A.,Bianchi, Bruce R.,Zhong, Chengmin,Joshi, Shailen,Honore, Prisca,Marsh, Kennan C.,Lee, Chih-Hung,Faltynek, Connie R.,Gomtsyan, Arthur
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p. 1338 - 1341
(2011/04/23)
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- Copper-catalyzed formation of carbon-heteroatom and carbon-carbon bonds
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The present invention relates to copper-catalyzed carbon-heteroatom and carbon-carbon bond-forming methods. In certain embodiments, the present invention relates to copper-catalyzed methods of forming a carbon-nitrogen bond between the nitrogen atom of an amide or amine moiety and the activated carbon of an aryl, heteroaryl, or vinyl halide or sulfonate. In additional embodiments, the present invention relates to copper-catalyzed methods of forming a carbon-nitrogen bond between a nitrogen atom of an acyl hydrazine and the activated carbon of an aryl, heteroaryl, or vinyl halide or sulfonate. In other embodiments, the present invention relates to copper-catalyzed methods of forming a carbon-nitrogen bond between the nitrogen atom of a nitrogen-containing heteroaromatic, e.g., indole, pyrazole, and indazole, and the activated carbon of an aryl, heteroaryl, or vinyl halide or sulfonate. In certain embodiments, the present invention relates to copper-catalyzed methods of forming a carbon-oxygen bond between the oxygen atom of an alcohol and the activated carbon of an aryl, heteroaryl, or vinyl halide or sulfonate. The present invention also relates to copper-catalyzed methods of forming a carbon-carbon bond between a reactant comprising a nucleophilic carbon atom, e.g., an enolate or malonate anion, and the activated carbon of an aryl, heteroaryl, or vinyl halide or sulfonate. Importantly, all the methods of the present invention are relatively inexpensive to practice due to the low cost of the copper comprised by the catalysts.
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- A general and efficient copper catalyst for the amidation of aryl halides
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An experimentally simple and inexpensive catalyst system was developed for the amidation of aryl halides by using 0.2-10 mol % of Cul, 5-20 mol % of a 1,2-diamine ligand, and K3PO4, K2CO3, or Cs2CO3 as base. Catalyst systems based on N, N′-dimethylethylenediamine or trans-N,N′-dimethyl-1,2-cyclohexanediamine were found to be the most active even though several other 1,2-diamine ligands could be used in the easiest cases. Aryl iodides, bromides, and in some cases even aryl chlorides can be efficiently amidated. A variety of functional groups are tolerated in the reaction, including many that are not compatible with Pd-catalyzed amidation or amination methodology.
- Klapars, Artis,Huang, Xiaohua,Buchwald, Stephen L.
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p. 7421 - 7428
(2007/10/03)
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- Acyloxylation at the 4-Position of Azetidin-2-ones
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The copper-catalysed reaction of azetidin-2-ones with t-butyl perbenzoate or peracetate affords the corresponding 4-benzoyloxy- and acetoxy-substituted β-lactams, respectively.N-Unsubstituted 4-acyloxyazetidinones can be synthesized by dearylation of the N-(4-methoxyphenyl)-substituted products with ceric ammonium nitrate.Acyloxylation of β-lactams that are monosubstituted at C-3 affords predominantly trans-products.
- Easton, Christopher J.,Love, Stephen G.,Wang, Peng
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p. 277 - 282
(2007/10/02)
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- A Convenient Synthesis of Monocyclic β-Lactams by Means of Solid-Liquid Phase Transfer Reactions
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The intramolecular N-alkylation of β-bromopropionamides (1) under phase transfer conditions afforded monocyclic N-substituted β-lactams (2) in high yields.In a similar manner, cyclization by N1-C4 bond formation gave 4-benzoyl-2-azet
- Takahata, Hiroki,Ohnishi, Yoshinori,Takehara, Hiroyuki,Tsuritani, Kazuko,Yamazaki, Takao
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p. 1063 - 1068
(2007/10/02)
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- Formation of 2,3-Dihydro-4(1H)-quinolones and Related Compounds via Fries-type Acid-catalysed Rearrangement of 1-Arylazetidin-2-ones
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A variety of 1-arylazetidin-2-ones were treated with trifluoroacetic acid under reflux, methanesulphonic acid at 100 deg C, or conc. sulphuric acid to give the corresponding 2,3-dihydro-4(1H)-quinolones via acyl migration and N-CO fission.In the case of 1-(3-substituted phenyl)azetidin-2-ones, two positional isomeric products, 5- and 7-substituted 2,3-dihydro-4(1H)-quinolones were obtained. 4-Methyl, 4-ethoxycarbonyl, and 4-piperidin-2-yl-1-arylazetidin-2-ones and their analogues were also converted into the corresponding 2-substituted 2,3-dihydro-4(1H)-quinolones under acidic conditions.The 3-substituted 1-phenylazetidin-2-ones (36) and (37) were converted into the furoquinoline systems (38) and (40), respectively, by application of this method.
- Kano, Shinzo,Ebata, Tsutomu,Shibuya, Shiroshi
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p. 2105 - 2111
(2007/10/02)
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