1,4,2-Dioxazol-5-ones as Isocyanate Equivalents: An Efficient Synthesis of 2-Quinolinones via β-Keto Amides
作者:Ramakrishna Guduru、Anand Vala、Nirali Parmar、Jigar Y Soni、Sharadsrikar Kotturi
DOI:10.1055/s-0040-1720889
日期:2021.12
Under thermal conditions, 1,4,2-dioxazol-5-ones are known to undergo decarboxylation followed by Lossen’s rearrangement to yield isocyanates. Described herein is the in situ trapping of the resulting isocyanates with carbon nucleophiles to synthesize β-keto amides. Furthermore, a general and mild method for the conversion of the resulting β-keto amides into quinolin-2-ones is reported.
Palladiumcatalysed addition of arylboronic acid to the readily available 2-cyano-(N-aryl)-acetamide or ethyl-2-cyanoacetate followed by subsequent reaction transform them into the biologically significant 4-arylquinolin-2-one or pyrazolone derivatives. The reaction conditions are robust enough to prevent the hydrolysis of ester/amide moiety during arylation. In addition, the unactivated nitrile moiety
The first direct use of carbon dioxide in the lactamization of alkenyl and heteroaryl C−H bonds to synthesize important 2‐quinolinones and polyheterocycles in moderate to excellent yields is reported. Carbon dioxide, a nontoxic, inexpensive, and readily available greenhouse gas, acts as an ideal carbonyl source. Importantly, this transition‐metal‐free and redox‐neutral process is eco‐friendly and desirable
Palladium-Catalyzed Multi-Component Reactions of<i>N</i>-Tosylhydrazones, 2-Iodoanilines and CO<sub>2</sub>towards 4-Aryl-2-Quinolinones
作者:Song Sun、Wei-Ming Hu、Ning Gu、Jiang Cheng
DOI:10.1002/chem.201604256
日期:2016.12.23
A palladium‐catalyzed three‐component reaction between N‐tosylhydrazones, 2‐iodoanilines and atmospheric pressure CO2 was developed whereby a tandem carbene migration insertion/lactamization strategy afforded 4‐aryl‐2‐quinolinones in moderate to good yields. Notably, a wide range of functional groups were tolerated in this procedure. This protocol features the simultaneous formation of four novel bonds;
Practical Route to 2-Quinolinones via a Pd-Catalyzed C–H Bond Activation/C–C Bond Formation/Cyclization Cascade Reaction
作者:Junliang Wu、Shaohua Xiang、Jing Zeng、Minli Leow、Xue-Wei Liu
DOI:10.1021/ol503292p
日期:2015.1.16
Quinolinone derivatives were constructed via a Pd-catalyzed C–H bond activation/C–Cbondformation/cyclization cascade process with simple anilines as the substrates. This finding provides a practical procedure for the synthesis of quinolinone-containing alkaloids and drug molecules. The utility of this method was demonstrated by a formal synthesis of Tipifarnib.