- One-pot B(C6F5)3 catalyzed cascade synthesis of 2-substituted-2,3-dihydroquinazolin-4(1H)-ones
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A new and efficient B(C6F5)3 catalyzed domino strategy has been developed for the synthesis of 2-substituted quinazolinones. The reaction utilizes 2-aminobenzamide and aldehydes for a one-pot protocol. A wide range of substrate scope, functional group tolerance, and operational simplicity with excellent yield are synthetically useful features.
- Shinde, Achut R.,Mane, Yogesh D.,Muley, Dnyanoba B.
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supporting information
p. 33 - 40
(2019/11/19)
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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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- 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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- Meridianin G and its analogs as antimalarial agents
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The marine-derived indole alkaloids meridianin C and G and their N1-substituted and C-ring modified analogs were synthesized and screened for antiprotozoal and antimicrobial activities. Meridianin C and G showed antimalarial activity against both chloroquine-resistant (D6) as well as sensitive (W2) clones of Plasmodium falciparum with IC50 values in the range of 4.4 to 14.4 μM. Meridianin G showed better activity against the W2 clone, showing a higher selectivity index >24.1. Among the analogs, N1-morpholinoyl meridianin C analog displayed antimalarial activity against both clones, showing selectivity indices up to 25.1. Meridianin C along with a few other analogs showed weak to moderate antileishmanial activity against Leishmania donovani promastigotes, the best analog being a C-ring modified 5-iodo meridianin showing an IC50 of 9.17 μM. A few compounds also showed mild antibacterial activity against Staphylococcus aureus and methicillin-resistant S. aureus, and antifungal activity against Cryptococcus neoformans.
- Bharate, Sandip B.,Yadav, Rammohan R.,Khan, Shabana I.,Tekwani, Babu L.,Jacob, Melissa R.,Khan, Ikhlas A.,Vishwakarma, Ram A.
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supporting information
p. 1042 - 1048
(2013/07/27)
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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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- Deformylation of indole and azaindole-3-carboxaldehydes using anthranilamide and solid acid heterogeneous catalyst via quinazolinone intermediate
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The deformylation of indole and azaindole-3-carboxaldehydes was achieved in the presence of anthranilamide and a solid acid heterogeneous catalyst under reflux conditions in 25-90% yield. The reaction proceeds via quinazolinone intermediate, which undergoes acid catalyzed cleavage to form deformylated product.
- Yadav, Rammohan R.,Battini, Narsaiah,Mudududdla, Ramesh,Bharate, Jaideep B.,Muparappu, Nagaraju,Bharate, Sandip B.,Vishwakarma, Ram A.
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scheme or table
p. 2222 - 2225
(2012/05/20)
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