Copper-Catalyzed Radical Methylation/C–H Amination/Oxidation Cascade for the Synthesis of Quinazolinones
摘要:
A copper-catalyzed radical methylation/sp(3) C-H amination/oxidation reaction for the facile synthesis of quinazolinone was developed. In this cascade reaction, dicumyl peroxide acts not only as a useful oxidant but also as an efficient methyl source. Notably, a methyl radical, generated. from peroxide, was confirmed by electron paramagnetic resonance for the first time.
transformations are based on the fact that DMF can serve as a reaction solvent and one carbon synthon for the construction of heterocyclic rings. Moreover, this protocol features base-free and Brønsted acid free environmentally benign conditions with broad synthetic scope. A good scalability is demonstrated.
<i>N</i>,<i>N</i>-Dimethylformamide as Carbon Synthons for the Synthesis of <i>N</i>-Heterocycles: Pyrrolo/Indolo[1,2-<i>a</i>]quinoxalines and Quinazolin-4-ones
作者:Shichen Li、Jianing Ren、Chengcheng Ding、Yishou Wang、Chen Ma
DOI:10.1021/acs.joc.1c02067
日期:2021.12.3
N-dimethylformamide (DMF) as synthetic precursors contributing especially the methyl, acyl, and amino groups has played a significant role in heterocycle syntheses and functionalization. In this protocol, a wide range of pyrrolo/indolo[1,2-a]quinoxalines and quinazolin-4-ones were obtained in moderate to good yields by using elemental iodine without any metal or peroxides. We considered that N-methyl and
N , N-二甲基甲酰胺 (DMF) 作为合成前体,尤其是甲基、酰基和氨基,在杂环合成和功能化中发挥了重要作用。在该协议中,通过使用不含任何金属或过氧化物的元素碘,以中等至良好的收率获得了范围广泛的 pyrrolo/indolo[1,2 - a ]quinoxalines 和 quinazolin-4-ones。我们认为DMF的N-甲基和N-酰基通过不同的机理分别参与并完成反应,这表明DMF的潜力仍有待探索。
Metal-free oxidative synthesis of quinazolinones via dual amination of sp<sup>3</sup> C–H bonds
作者:Dan Zhao、Teng Wang、Jian-Xin Li
DOI:10.1039/c4cc02648a
日期:——
A novel metal-free synthesis of quinazolinones via dual amination of sp3 C–H bonds was developed. The sp3 carbon in methylarenes or adjacent to a heteroatom in DMSO, DMF or DMA was used as the one carbon synthon.
An efficient synthesis of substituted quinazolin-4(3H)-ones by a one-pot ligand-free CuI-catalyzed coupling/condensative cyclization under mild conditions is described. Our study provides an alternative strategy for the preparation of biologically active quinazolin-4(3H)-ones.