- Potassium tert-Butoxide Promoted Synthesis of Dihydroquinazolinones
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We herein report an efficient synthetic protocol to access heterocyclic dihydroquinazolinones by a transition-metal-free process, involving the reaction of 2-aminobenzonitriles with aldehydes in the presence of KOtBu. The method is compatible with aromatic ketones providing 2,2-disubstituted dihydroquinazolinones in high yields. This reaction proceeds feasibly at room temperature and features a broad substrate scope and tolerance to a range of functional groups. The mechanism follows a radical pathway.
- Basak, Soumya Jyoti,Dash, Jyotirmayee,Ghosh, Tridev,Mandal, Indradip
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supporting information
p. 14695 - 14704
(2021/10/20)
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- A Facile Microwave and SnCl2Synthesis of 2,3-Dihydroquinazolin-4(1 H)-ones
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An elegantly simple, facile, and robust approach to a scaffold of biological importance, 2,3-dihydroquinazolin-4(1H)-ones, is reported. A catalytic 1 % SnCl2/microwave-mediated approach afforded access to pure material, collected by cooling and filtration after 20-min microwave irradiation at 120°C. A total of 41 analogues were prepared in isolated yields of 17-99 %. This process was highly tolerant of aliphatic, aromatic, heterocyclic, and acyclic aldehydes, but furan, pyrrole, and thiophene aldehyde reactivity correlated with propensity towards electrophilic addition and/or Diels-Alder addition. As a result, thiophene afforded high yields (80 %) whereas pyrrole carboxaldehyde failed to react. With simple cinnamaldehydes, and in the SbCl3-mediated reaction, and with α,β-unsaturated aldehydes the equivalent quinazolin-4(3H)-ones, and not the 2,3-dihydroquinazolin-4(1H)-ones, was favoured.
- O'brien, Nicholas S.,McCluskey, Adam
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p. 1176 - 1186
(2020/10/06)
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- Green and efficient one-pot synthesis of 2,3-dihydroquinazolin-4(1H)-ones and their anthelmintic studies
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A facile and highly efficient one-pot synthesis of 2,3-dihydroquinazolin-4(1H)-ones derivatives has been developed by the condensation of anthranilamide with aldehydes using sulfonic acid functionalized l-Proline?Fe3O4 nanoparticles as a catalyst. The advantages of this protocol are easy recovery and reusability of the catalyst besides simple work-up procedure and short reaction time. In addition, the anthelmintic activities of some selective compounds were investigated and it was found that 2-phenyl-2,3-dihydroquinazolin-4(1H)-one exhibited profound anthelmintic activity against two helminth models.
- Kharmawlong, George Kupar,Nongrum, Ridaphun,Chhetri, Bhusan,Rani, Jims World Star,Rahman, Noimur,Yadav, Arun Kumar,Nongkhlaw, Rishanlang
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supporting information
p. 2683 - 2695
(2019/08/07)
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- Phosphotungstic acid mediated, microwave assisted solvent-free green synthesis of highly functionalized 2?-spiro and 2, 3-dihydro quinazolinone and 2-methylamino benzamide derivatives from aryl and heteroaryl 2-amino amides
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Phosphotungstic acid has been found as green catalyst for the synthesis of spiro and cyclized quinazolinones and 2-amino substituted carboxamide under microwave irradiation and solvent-free condition has been developed. The scope of the reaction has been demonstrated for a variety of aldehydes and ketones with O-amino amides such as 2-amino-benzamide, 2-amino-5-iodo benzamide, 3-aminothiophene-2-carboxamide, 3-aminobenzofuran-2-carboxamide and 2-aminopyridine-3-carboxamides. The reaction afforded spiro-, cyclized quinazolinones and 2-amino substituted carboxamide derivatives within few minutes of irradiation in excellent yield. Plausible mechanism for the formation of products is provided. Synthetic utility of 1′H-spiro[fluorene-9,2′-quinazolin]-4′(3′H)-one 3a has been demonstrated by synthesis of 1,4-di(1′H-spiro[fluorene-9,2′-quinazolin]-4′(3′H)-one) buta-1,3-diyne 12, 1′-((1-benzyl-1H-1,2,3-triazol-4-yl) methyl)-1′H-spiro[fluorene-9,2′-quinazolin]-4′(3′H)-one 13 and 1′-phenyl-1′H-spiro[fluorene-9,2′-quinazolin]-4′(3′H)-one 14 under standard protocols.
- Novanna, Motakatla,Kannadasan, Sathananthan,Shanmugam, Ponnusamy
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supporting information
p. 201 - 206
(2018/12/13)
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- Recyclable [Ce(l -Pro) 2 ] 2 (Oxa) used as Heterogeneous Catalyst: One-Pot Synthesis of 2,3-Dihydroquinazolin-4(1 H)-ones in Ethanol
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[Ce(l -Pro) 2 ] 2 (Oxa) was used as a recyclable heterogeneous catalyst under mild conditions for the preparation of 2-aryl-2,3-dihydroquinazolin-4(1 H)-one derivatives. The one-pot protocol proceeds in ethanol using anthranilamide with several aldehydes at 50-55 °C. The catalyst can be recycled and reused three cycles without significant loss of catalytic activity.
- Katla, Ramesh,Chowrasia, Rakhi,Da Silva, Caren D. G.,De Oliveira, Aline R.,Dos Santos, Beatriz F.,Domingues, Nelson L. C.
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supporting information
p. 5143 - 5148
(2017/10/07)
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- Method for synthesis of quinazolinone derivative
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The invention discloses a method for synthesis of quinazolinone; the method comprises the steps of starting from o-aminobenzamide, taking water as a solvent, carrying out a ring-enlargement reaction with benzaldehyde, to generate a dihydroquinazolinone intermediate, and then under participation of a metal iridium complex, dehydrogenating to obtain the quinazolinone derivative; the reaction shows three remarkable advantages: 1) the reaction is carried out in an aqueous solution so as to reduce use of a large amount of organic solvents, and water is a cheap, green and safe solvent; 2) the reaction avoids use of highly toxic oxidants, so as to avoid damage to the environment; and 3) hydrogen gas generated from the reaction is a by-product, and has no environmental pollution; therefore, the reaction accords with the requirements of green chemistry, and has broad prospects for development.
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Paragraph 0097-0100
(2017/04/20)
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- Green protocol for synthesis of 2,3-dihydroquinazolin-4(1H)-ones: lactic acid as catalyst under solvent-free condition
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Abstract: In the present work, lactic acid was used as novel, green catalyst for synthesis of 2,3-dihydroquinazolin-4(1H)-one derivatives via two distinct methods, including reaction of 2-aminobenzamide with aldehydes/ketones or isatoic anhydride with ammonium acetate and aldehydes in neat condition at 70?°C. The desired products were obtained in satisfactory yields. Short reaction time, easy workup, and more importantly environmental benignity are the most outstanding advantages of these procedures. Graphical Abstract: [Figure not available: see fulltext.]
- Zhaleh, Sara,Hazeri, Nourallah,Maghsoodlou, Malek Taher
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p. 6381 - 6390
(2016/07/06)
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- 3,3′-(butane-1,4-diyl)bis(1,2-dimethyl-1H-imidazol-3-ium) dibromide [BDBIm] Br-An efficient reusable ionic liquid for the microwave-assisted synthesis of quinazolinones
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A series of 2-substituted quinazolin-4(1H)-ones have been synthesized in excellent yields and short reaction times by one-pot reaction of isatoic anhydride with ammonium acetate and aromatic aldehydes under microwave irradiation. The reaction was efficiently promoted by 0.5 mmol of 3,3′-(butane-1,4-diyl)bis(1,2-dimethyl-1H-imidazol-3-ium) dibromide [BDBIm] Br, and the catalyst could be recovered easily and reused without appreciable loss of reactivity.
- Nikpassand,Zare Fekri,Sina,Abed,Marvi
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p. 1959 - 1964
(2015/10/12)
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- Tandem supramolecular synthesis of substituted 2-aryl-2,3- dihydroquinazolin-4(1H)-ones in the presence of β-cyclodextrin in water
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Substituted 2-aryl-2,3-dihydroquinazolin-4(1H)-ones were prepared for the first time in water under neutral conditions by the reaction of aniline, isatoic anhydride, and aldehyde mediated by β-cyclodextrin in good yields. β-Cyclodextrin can be recovered a
- Ramesh,Karnakar,Satish,Harsha Vardhan Reddy,Nageswar
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supporting information
p. 6095 - 6099
(2012/11/07)
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- A concise aqueous phase supramolecular synthesis of 2-phenyl-2,3- dihydroquinazolin-4(1H)-one derivatives
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2-Phenyl-2,3-dihydroquinazolin-4(1H)-one derivatives were synthesized for the first time in water under neutral conditions by the reaction of aldehyde, and anthranilamide mediated by β-cyclodextrin in high yields. β-Cyclodextrin can be recovered and reused with a small loss of catalytic activity.
- Ramesh,Karnakar,Satish,Anil Kumar,Nageswar
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supporting information
p. 6936 - 6939
(2013/01/15)
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- Efficient synthesis of 2,3-dihydroquinazolin-4(1H)-ones using heterogeneous solid acid catalysts: Unexpected formation of 2,3-dihydro-2-(4-(tetrahydro-2H- pyran-2-yloxy)butyl)quinazolin-4(1H)-one
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The heterogeneous solid acid catalysts Amberlyst-15 and silica-HClO 4 displays efficient catalytic properties for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones from anthranilamide and various aldehydes/ketones under mild reaction conditions and in good yields. These catalysts also showed good catalytic activity for condensation of anthranilamide with a cyclic enol ether 3,4-dihydropyran and led to formation of new unexpected quinazolinone product 6 comprising two dihydropyran moieties. The new product 6 has been reported for the first time and is fully characterized using 2D-NMR data. Furthermore, both solid acid catalysts can be easily recycled without significant loss of activity. ARKAT-USA, Inc.
- Bharate, Sandip B.,Mupparapu, Nagaraju,Manda, Sudhakar,Bharate, Jaideep B.,Mudududdla, Ramesh,Yadav, Rammohan R.,Vishwakarma, Ram A.
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p. 308 - 318
(2012/10/29)
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