- Visible light induced tandem reactions: An efficient one pot strategy for constructing quinazolinones using in-situ formed aldehydes under photocatalyst-free and room-temperature conditions
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A facile tandem route has been developed for constructing quinazolinones from various aminobenzamides and in-situ generated aldehydes. Visible light was found to play a dual role: first oxidizes the alcohol to the aldehyde and then facilitates its cyclization with o-substituted aniline. Furthermore, alcohols are perfect alternatives to aldehydes because they are greener, more available, more economical, more stable, and less toxic than aldehydes. The first reaction step continuously provides material for the second step, which effectively reduces loss through volatilization, oxidation, and polymerization of the aldehyde, while avoiding its toxicity. A variety of quinazolinones can be prepared in the presence of visible light without any additional photocatalyst. The developed synthesis protocol proceeds with the merits of mild conditions, broad substrate scope, operational simplicity, and high atom efficiency, with an eco-energy source under metal-free, photocatalyst-free, and ambient conditions.
- Xie, Zongbo,Lan, Jin,Zhu, Haibo,Lei, Gaoyi,Jiang, Guofang,Le, Zhanggao
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supporting information
p. 1427 - 1431
(2020/11/02)
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- Cobalt-Catalyzed Tandem Transformation of 2-Aminobenzonitriles to Quinazolinones Using Hydration and Dehydrogenative Coupling Strategy
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A tandem synthesis of quinazolinones from 2-aminobenzonitriles is demonstrated here by using an aliphatic alcohol-water system. For this transformation, a cheap and easily available cobalt salt and P(CH2CH2PPh2)3 (PP3) ligand were employed. The substrate scope, scalability, and synthesis of natural products exhibited the vitality of this protocol.
- Samim, Sk. Abdus,Roy, Bivas Chandra,Nayak, Sourav,Kundu, Sabuj
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p. 11359 - 11367
(2020/10/12)
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- One-pot synthesis of quinazolin-4(3H)-ones and 2,3-dihydroquinazolin-4(1H)-ones utilizing N-(2-aminobenzoyl)benzotriazoles
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A convenient and efficient method has emerged for the one-pot synthesis of substituted quinazolin-4(3H)ones and nonaromatic alkaloids. 2-Substituted quinazolin-4(3H)-ones, 2,3-disubstituted quinazolin-4(3H)-ones, and 2,3-dihydroquinazolin-4(1H)-ones were obtained at yields of 46% to 95% by a one-pot reaction of N-(2-aminobenzoyl) benzotriazoles with amines and orthoesters or aldehydes under catalyst-free conditions.
- ?enol, ?lbilge Merve,?elik, ?lhami,Avan, ?lker
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p. 1580 - 1596
(2020/01/03)
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- Quinazolin-4(3H)-ones and 5,6-dihydropyrimidin-4(3H)-ones from β-aminoamides and orthoesters
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Quinazolin-4(3H)-ones have been prepared in one step from 2-aminobenzamides and orthoesters in the presence of acetic acid. Simple 2-aminobenzamides were easily converted to the heterocycles by refluxing in absolute ethanol with 1.5 equivalents of the orthoester and 2 equivalents of acetic acid for 12–24 h. Ring-substituted and hindered 2-aminobenzamides as well as cases incorporating an additional basic nitrogen required pressure tube conditions with 3 equivalents each of the orthoester and acetic acid in ethanol at 110?C for 12–72 h. The reaction was tolerant towards functionality on the benzamide and a range of structures was accessible. Workup involved removal of the solvent under vacuum and either recrystallization from ethanol or trituration with ether-pentane. Several 5,6-dihydropyrimidin-4(3H)-ones were also prepared from 3-amino-2,2-dimethylpropionamide. All products were characterized by melting point, FT-IR, 1H-NMR, 13C-NMR, and HRMS.
- Gavin, Joshua T.,Annor-Gyamfi, Joel K.,Bunce, Richard A.
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- Metal-free oxidative cyclization of 2-amino-benzamides, 2-aminobenzenesulfonamide or 2-(aminomethyl)anilines with primary alcohols for the synthesis of quinazolinones and their analogues
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A general metal-free oxidative cyclization process has been developed for the synthesis of quinazolinones, benzothiadiazines and quinazolines. By this protocol, a range of substituted 2-aminobenzamides, 2-aminobenzenesulfonamide and 2-(aminomethyl)anilines react with various alcohols, leading to the desired annulated products smoothly. This protocol features many advantages as broad substrate scope, mild reaction conditions, low environmental pollution, high atom-economy and good to excellent yields.
- Sun, Jinwei,Tao, Tao,Xu, Dan,Cao, Hui,Kong, Qinggang,Wang, Xinyu,Liu, Yun,Zhao, Jianglin,Wang, Yi,Pan, Yi
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p. 2099 - 2102
(2018/05/04)
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- YB(OTF)3-catalyzed synthesis of 2-substituted 4(3H)- quinazolinones via cleavage of a carbon-carbon bond
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A general, selective, and practical one-pot synthesis of 2-substituted 4(3H)-quinazolinones by the Yb(OTf)3-catalyzed cyclo-condensation of 2-Aminobenzamides with acyclic or cyclic 1,3-diketones (β-diketones) under mild and neutral reaction conditions has been developed, which involves the highly selective cleavage of a C-C bond in 1,3-diketones by Yb(OTf)3 catalyst. For example, the Yb(OTf)3-catalyzed cyclo-condensation of 2-Aminobenzamide (1a) with 1-phenylbutane-1,3-dione (2c) gave 2-methyl-4(3H)-quinazolinone (3a) in 90% yield, together with acetophenone in 65% yield. Ring-opening cyclo-condensation of 2-Aminobenzamides (1a) with cyclic 1,3-diketones (2i and 2k-m), except for cyclopentane-1,3-dione (2j), gave 2-substitued 4(3H)-quinazolinones (3i and 3k-m) with one carbonyl group.
- Yoshimura, Tsutomu,Naito, Shun-Ichi,Yuanjun, Di,Son, Aoi,Kimura, Yu,Toshimitsu, Akio,Kondo, Teruyuki
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p. 816 - 823
(2017/04/10)
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- Discovery and structure-activity relationships of 4-aminoquinazoline derivatives, a novel class of opioid receptor like-1 (ORL1) antagonists
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Synthesis and structure-activity relationship studies of a series of 4-aminoquinazoline derivatives led to the identification of (1R,2S)-17, N-[(1R,2S)-2-({2-[(4-chlorophenyl)carbonyl]amino-6-methylquinazolin-4-yl}amino)cyclohexyl]guanidine dihydrochloride, as a highly potent ORL1 antagonist with up to 3000-fold selectivity over the μ, δ, and κ opioid receptors. Molecular modeling clarified the structural factors contributing to the high affinity and selectivity of (1R,2S)-17.
- Okano, Masahiko,Mito, Jun,Maruyama, Yasufumi,Masuda, Hirofumi,Niwa, Tomoko,Nakagawa, Shin-ichiro,Nakamura, Yoshitaka,Matsuura, Akira
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experimental part
p. 119 - 132
(2011/02/25)
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