- Direct synthesis of quinazolinones via the carbon-supported acid-catalyzed cascade reaction of isatoic anhydrides with amides and aldehydes
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A novel catalytic system is reported for the construction of quinazolinones via the carbon-supported acid-catalyzed cascade coupling of isatoic anhydrides with amides and aldehydes. Subsequent selective hydrosilylation of the quinazolinones using a hydrogen-transfer strategy was also explored to provide dihydroquinazolines with structural diversity. The developed methodology proceeds with a broad substrate scope, excellent functional group tolerance, and utilizes a reusable catalyst and air as a green oxidant.
- Zhang, Xiangyu,Luo, Chujun,Chen, Xiaoyong,Ma, Weilin,Li, Bin,Lin, Zirui,Chen, Xiuwen,Li, Yibiao,Xie, Feng
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- Synthesis of 2-aryl quinazolinones: Via iron-catalyzed cross-dehydrogenative coupling (CDC) between N-H and C-H bonds
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Herein, we describe the direct synthesis of quinazolinones via cross-dehydrogenative coupling between methyl arenes and anthranilamides. The C-H functionalization of the benzylic sp3 carbon is achieved by di-t-butyl peroxide under air, and the subsequent amination-aerobic oxidation process completes the annulation process. Iron catalyzed the whole reaction process and various kinds of functional groups were tolerated under the reaction conditions, providing 31 examples of 2-aryl quinazolinones using methyl arene derivatives in yields of 57-95percent. The synthetic potential has been demonstrated by the additional synthesis of aryl-containing heterocycles. This journal is
- Jang, Yoonkyung,Lee, Seok Beom,Hong, Junhwa,Chun, Simin,Lee, Jeeyeon,Hong, Suckchang
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supporting information
p. 5435 - 5441
(2020/08/03)
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- N3-Alkylation during formation of quinazolin-4-ones from condensation of anthranilamides and orthoamides
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Dimethylformamide dimethylacetal (DMFDMA) is widely used as a source of electrophilic one-carbon units at the formate oxidation level; however, electrophilic methylation with this reagent is previously unreported. Reaction of anthranilamide with DMFDMA at 150 °C for short periods gives mainly quinazolin-4-one. However, prolonged reaction with dimethylformamide di(primary-alkyl)acetals leads to subsequent alkylation at N3. 3-Substituted anthranilamides give 8-substituted 3-alkylquinazolin-4-ones. Condensation of anthranilamides with dimethylacetamide dimethylacetal provides 2,3-dimethylquinazolin-4-ones. In these reactions, the source of the N 3-alkyl group is the O-alkyl group of the orthoamides. By contrast, reaction with the more sterically crowded dimethylformamide di(isopropyl)acetal diverts the alkylation to the oxygen, giving 4-isopropoxyquinazolines, along with N3-methylquinazolin-4-ones where the methyl is derived from N-Me of the orthoamides. Reaction of anthranilamide with the highly sterically demanding dimethylformamide di(t-butyl)acetal gives largely quinazolin-4-one, whereas dimethylformamide di(neopentyl)acetal forms a mixture of quinazolin-4-one and N3-methylquinazolin-4-one. The observations are rationalised in terms of formation of intermediate cationic electrophiles (alkoxymethylidene-N,N-dimethylammonium) by thermal elimination of the corresponding alkoxide from the orthoamides. These are the first observations of orthoamides as direct alkylating agents.
- Nathubhai, Amit,Patterson, Richard,Woodman, Timothy J.,Sharp, Harriet E. C.,Chui, Miranda T. Y.,Chung, Hugo H. K.,Lau, Stephanie W. S.,Zheng, Jun,Lloyd, Matthew D.,Thompson, Andrew S.,Threadgill, Michael D.
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experimental part
p. 6089 - 6099
(2011/10/08)
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- Polycyclic N-heterocyclic compounds. Part 601): Reactions of 3-(2-cyanophenyl)quinazolin-4(3H)-ones with primary amines
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The reaction of 3-(2-cyanophenyl)quinazolin-4(3H)-one with various primary alkylamines gave 3-alkylquinazolin-4(3H)-ones via an addition of the nucleophile, ring opening, and ring closure (ANRORC) mechanism. This type of reaction required hydroxy group fu
- Okuda, Kensuke,Tagata, Tsuyoshi,Kashino, Setsuo,Hirota, Takashi,Sasaki, Kenji
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experimental part
p. 1296 - 1299
(2010/05/02)
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- A Facile Synthesis of 3-Substituted 2-Cyanoqmnazolin-4(3H)-ones and 3-Alkyl-2-cyanothieno[3,2-d]pyrimidin-4(3H)-ones via 1,2,3-Dithiazoles
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The reaction of methyl anthranilate with 4,5-dichloro-l,2,3-dithiazolium chloride (Appel's salt) in the presence of pyridine (2 equivalents) in dichloromethane at room temperature gave methyl N-(4-chloro-5H-l,2,3-dithiazol-5-ylidene)anthranilate (3a) (50% yield), which reacted with sterically less hindered primary alkylamines to give directly 3-alkyl-2-cyanoquinazolin-4(3H)-ones 5 in moderate to good yields. With tertbutylamine, N-(2-methoxycarbonylphenyl)iminocyanomethyl N-(tert-butyl) disulfide 7 and methyl 2-(N-cyanothioformamido)anthranilate (8) were isolated in 33% and 59% yields, respectively. The cyano group of quinazoline 5a (R = CH3) is readily displaced by various nucleophiles to give 2-substituted quinazolinones 11-19, which indicates that compounds 5 can be utilized as starting materials for the synthesis of new 2-substituted quinazolines. Similarly 3-alkyl-2-cyanothieno[3,2,-d]pyrimidin-4(3H)-ones 22 were prepared from methyl 3-[N-(4-chloro-5H-l,2,3-dithiazol-5-ylidene)]-2-thiophencarboxylate (21) in moderate to good yields.
- Lee, Hyi-Seung,Chang, Yong-Goo,Kim, Kyongtae
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p. 659 - 668
(2007/10/03)
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