2436-66-0Relevant articles and documents
Direct synthesis of quinazolinones via the carbon-supported acid-catalyzed cascade reaction of isatoic anhydrides with amides and aldehydes
Zhang, Xiangyu,Luo, Chujun,Chen, Xiaoyong,Ma, Weilin,Li, Bin,Lin, Zirui,Chen, Xiuwen,Li, Yibiao,Xie, Feng
, (2021/02/20)
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.
N3-Alkylation during formation of quinazolin-4-ones from condensation of anthranilamides and orthoamides
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.
experimental part, p. 6089 - 6099 (2011/10/08)
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.
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
Lee, Hyi-Seung,Chang, Yong-Goo,Kim, Kyongtae
, p. 659 - 668 (2007/10/03)
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.
