- α-Keto Acids as Triggers and Partners for the Synthesis of Quinazolinones, Quinoxalinones, Benzooxazinones, and Benzothiazoles in Water
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A general and efficient method for the synthesis of quinazolinones, quinoxalinones, benzooxazinones, and benzothiazoles from the reactions of α-keto acids with 2-aminobenzamides, benzene-1,2-diamines, 2-aminophenols, and 2-aminobenzenethiols, respectively, is described. The reactions were conducted under catalyst-free conditions, using water as the sole solvent with no additive required, and successfully applied to the synthesis of sildenafil. More importantly, these reactions can be conducted on a mass scale, and the products can be easily purified through filtration and washing with ethanol (or crystallized).
- Huang, Jian,Chen, Wei,Liang, Jiazhi,Yang, Qin,Fan, Yan,Chen, Mu-Wang,Peng, Yiyuan
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p. 14866 - 14882
(2021/10/25)
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- A niobium-catalyzed coupling reaction of α-keto acids with: Ortho -phenylenediamines: Synthesis of 3-arylquinoxalin-2(1 H)-ones
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A general methodology to access valuable 3-arylquinoxalin-2(1H)-ones was developed, by the reaction of α-keto acids with ortho-phenylenediamines in the presence of ammonium niobium oxalate (ANO) as a catalyst. The reactions were conducted in only 10 min under ultrasonic irradiation as an alternative energy source, affording water as the only co-product. A total of twenty-three different 3-arylquinoxalin-2(1H)-ones were selectively obtained in good to excellent yields by this atom-efficient protocol. Additionally, 1H-15N HMBC experiments were used to reveal the regioisomerism of the obtained products.
- Ebersol, Camila,Rocha, Nicole,Penteado, Filipe,Silva, Márcio S.,Hartwig, Daniela,Lenard?o, Eder J.,Jacob, Raquel G.
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supporting information
p. 6154 - 6160
(2019/11/20)
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- Solid Phase Synthesis of (Benzannelated) Six-Membered Heterocycles via Cyclative Cleavage of Resin-Bound Pseudo-Oxazolones
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A solid supported procedure for the synthesis of benzoxazinones, dihydropyrazinones, quinoxalinones, and dihydrooxazinones using immobilized oxazolones in combination with difunctional nucleophiles as cleavage agent is presented. The scope of the novel me
- Gr??le, Simone,Vanderheiden, Sylvia,Hodapp, Patrick,Bulat, Bekir,Nieger, Martin,Jung, Nicole,Br?se, Stefan
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supporting information
p. 3598 - 3601
(2016/08/16)
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