- Designing and Accurately Developing a [6 + 2] Dipolar Cycloaddition for the Synthesis of Benzodiazocines
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1,6-Dipolar cycloadditions represent a valuable strategy for the rapid construction of medium-sized rings. Herein, we describe the concept for the design of 1,6-dipoles that bypasses the regioselectivity. Through the introduction of an amino group into Morita-Baylis-Hillman (MBH) carbonates, unprecedented [6 + 2] dipolar cycloadditions were accurately developed with Cs2CO3, efficiently delivering a series of benzodiazocines in mild conditions. Computational studies bring a deeper understanding of this reaction.
- Cai, Wei,Chen, Kaihong,He, Yanlin,Huang, You,Yu, Cui,Zhou, Yiming
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supporting information
p. 5430 - 5434
(2021/07/26)
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- Benzoazepine-Fused Isoindolines via Intramolecular (3 + 2)-Cycloadditions of Azomethine Ylides with Dinitroarenes
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Aminobenzaldehydes bearing a pendant 3,5-dinitrophenyl group react thermally with N-substituted α-amino acids to form unprecedented benzoazepine-fused isoindolines. The reaction proceeds via a dearomatization/rearomatization sequence involving an intramolecular (3 + 2)-cycloaddition between the in situ formed azomethine ylide and the dinitroarene. Various glycine derivatives are tolerated as well as branched substrates based on cyclic, α-mono-, and α,α-disubstituted amino acids, giving single diastereomers in many cases. The method is scalable and gives products with a nitro group ready for further manipulation.
- Wales, Steven M.,Rivinoja, Daniel J.,Gardiner, Michael G.,Bird, Melissa J.,Meyer, Adam G.,Ryan, John H.,Hyland, Christopher J. T.
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p. 4703 - 4708
(2019/06/27)
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- Design and synthesis of novel benzoxazole analogs as Aurora B kinase inhibitors
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A novel series of benzoxazole analogs was designed and synthesized, and their inhibitory activities against Aurora kinases were evaluated. Some of the tested compounds exhibited a promising activity with respect to the inhibition of Aurora B kinase. A structure-activity relationship study indicated that linker length, regiochemistry, and halogen substitution play important roles in kinase inhibitory potency. The binding modes between representative compounds and Aurora kinases were interpreted through a molecular docking study to explain the inhibitory activity and selectivity for Aurora A and B kinases. Compounds 13l and 13q also show an antiproliferative effect on the human tumor cell lines in a dose-dependent manner. The most potent 13q demonstrated good efficacy in the prostate cancer PC-3 tumor xenograft model.
- An, Ying,Lee, Eun,Yu, Yeongji,Yun, Jieun,Lee, Myeong Youl,Kang, Jong Soon,Kim, Woo-Young,Jeon, Raok
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p. 3067 - 3072
(2016/06/13)
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- Nickel-catalyzed dehydrogenative cross-coupling: Direct transformation of aldehydes into esters and amides
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By exploring a new mode of nickel-catalyzed cross-coupling, a method to directly transform both aromatic and aliphatic aldehydes into either esters or amides has been developed. The success of this oxidative coupling depends on the appropriate choice of catalyst and organic oxidant, including the use of either α,α,α-trifluoroacetophenone or excess aldehyde. Mechanistic data that supports a catalytic cycle involving oxidative addition into the aldehyde C-H bond is also presented.
- Whittaker, Aaron M.,Dong, Vy M.
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supporting information
p. 1312 - 1315
(2015/01/30)
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- Synthesis of 1-acyl-3,4-dihydroquinazoline-2(1H)-thiones by cyclization of N-[2-(isothiocyanatomethyl)phenyl] amides generated in situ from N-[2-(azidomethyl)phenyl] amides
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An efficient method for the preparation of 1-acyl-3,4-dihydroquinazoline- 2(1H)-thiones 5 has been developed. The reaction of N-[2-(azidomethyl)phenyl] amides 3, easily prepared by a three-step sequence starting with (2-aminophenyl)methanols, with Ph
- Kobayashi, Kazuhiro,Matsumoto, Naoki
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p. 923 - 930
(2014/08/05)
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- A convenient allenoate-based synthesis of 2-quinolin-2-yl malonates and β-ketoesters
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N-Protected o-aminobenzaldehydes smoothly react with α,γ-dialkylallenoates under Bronsted basic conditions to yield 2,3-disubstituted quinolines. This three-step reaction cascade of Michael addition, aldol condensation, and 1,3-N → C rearrangement uses the complete protecting group as a building block in a highly efficient C,C-bond formation of a new all-carbon quaternary center. Carbamate protected substrates (N-Boc, N-Cbz, N-Alloc) thus give 2-quinolin-2-yl-malonates, while amide protected substrates (N-Ac, N-Bz) afford 2-quinolin-2-yl-β-ketoesters in high yields.
- Selig, Philipp,Raven, William
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supporting information
p. 5192 - 5195
(2014/12/11)
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- The synthesis and characterization of several corroles
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Preliminary results towards the synthesis of a corrole-based vitamin B 12 analogue are reported. The synthesis of three simple corroles, 5,10,15-triphenylcorrole (TPCrl), 5,10,15-tri(2-nitrophenyl)corrole and 10-(4-methoxyphenyl)-5,15-diphenylcorrole is described. The synthesis of 10-[2-(benzoylamino)phenyl]-5,15-diphenylcorrole (DPAPCrl) suggests that a large, bulky meso substituent can be incorporated into the corrole with no loss of stability or significant decrease in yield. Both TPCrl and DPAPCrl were crystallized and their crystal structure is reported.
- Zipp, Caitlin F.,Michael, Joseph P.,Fernandes, Manuel A.,Marques, Helder M.
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p. 158 - 166
(2013/07/26)
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- Preparation of functional benzofurans, benzothiophenes, and indoles using ester, thioester, and amide via intramolecular wittig reactions
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Preparation of new types of highly functional benzofurans, benzothiophenes, and indoles is realized via intramolecular Wittig reactions with the corresponding ester, thioester, and amide functionalities. The key intermediates, phosphorus ylides, presumably result from the addition of Bu 3P toward aldehydes followed by acylation and deprotonation. Synthesis of functional benzofurans directly starting from salicylic aldehyde derivatives with acid chlorides in a one-step procedure is also developed.
- Syu, Siang-En,Lee, Yu-Ting,Jang, Yeong-Jiunn,Lin, Wenwei
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supporting information; experimental part
p. 2970 - 2973
(2011/06/27)
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- Kinetics and mechanism of the addition of water and ring-opening of 2-methyl- and 2-aryl-4H-3,1-benzoxazines to 2-aminobenzyl esters in the acidic pH range; change in rate-limiting step with buffer concentration and evidence for a tetrahedral carbonyl addition intermediate
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The observed rate coefficients for the reaction of 2-methyl-, 2-phenyl- and 2-(4-nitrophenyl)-4H-3,1-benzoxazines to give the corresponding 2-aminobenzyl esters increase as the pH is lowered and reach a constant plateau value at pH 2-4 depending on the substituent. The plateau region corresponds to complete conversion of the benzoxazine to the protonated benzoxazine (SH+) which is the reactive species. Values of pKSH+ calculated by fitting the appropriate rate expression to the rate-pH profile and the pKSH+ values measured spectrophotometrically before significant reaction to the ester has taken place are in good agreement. For each benzoxazine the observed rate coefficients show a rectilinear dependence on buffer concentration. A mechanism is proposed involving addition of water to the protonated benzoxazine to give a cyclic tetrahedral carbonyl addition intermediate. At low buffer concentrations, buffer catalysed collapse of the intermediate to product is rate-limiting and the reaction is first order in buffer. At high buffer concentrations, collapse of the intermediate to product is rapid and addition of water to the protonated benzoxazine to give the intermediate is rate-limiting.
- Dixon, Wendy J.,Hibbert, Frank,Mills, Judith F.
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p. 1503 - 1509
(2007/10/03)
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