Photoinduced and N-Bromosuccinimide-Mediated Cyclization of 2-Azido-N-phenylacetamides
摘要:
An efficient synthesis of quinoxalin-2(1H)-ones or spiro[cyclohexene-1,2'-imidazol]-4'-cones has been achieved in moderate to high yields by the visible light-induced and N-bromosuccinimide-mediated cyclization reaction of 2-azido-N-phenylacetamides at ambient temperature. Both the regioselectivity and the speed of cyclization are affected by the substituents attached to the phenyl ring. For example, quinoxalin-2-ones are produced as the main products when the substrates bear electron-withdrawing groups at the para-position of the phenyl ring; in contrast, spiro[cyclohexene-1,2'-imidazol]-4'cones are obtained as the main products when the substrates bear electron-donating groups at the para-position.
C−H Methylation of Iminoamido Heterocycles with Sulfur Ylides**
作者:Prithwish Ghosh、Na Yeon Kwon、Saegun Kim、Sangil Han、Suk Hun Lee、Won An、Neeraj Kumar Mishra、Soo Bong Han、In Su Kim
DOI:10.1002/anie.202010958
日期:2021.1.4
The direct methylation of N‐heterocycles is an important transformation for the advancement of pharmaceuticals, agrochemicals, functional materials, and other chemical entities. Herein, the unprecedented C(sp2)‐H methylation of iminoamido heterocycles as nucleoside base analogues is described. Notably, trimethylsulfoxonium salt was employed as a methylating agent under aqueous conditions. A wide substrate
Metal Free Benzylation and Alkylation of Quinoxalin‐2(1
<i>H</i>
)‐ones with Alkenes Triggered by Sulfonyl Radical Generated from Sulfinic Acids
作者:Himangsu Sekhar Dutta、Ashfaq Ahmad、Afsar Ali Khan、Mohit Kumar、Raziullah、Dipankar Koley
DOI:10.1002/adsc.201901212
日期:2019.12.17
A metal‐free domino multicomponent reaction for the direct C−H benzylation and alkylation of quinoxalin‐2(1H)‐ones using alkenes is described. Triggered by the sulfonyl radical generated from sulfinic acid, the alkenes are transformed to alkyl radicals that react exclusively at the C‐3 position of quinoxalin‐2(1H)‐ones. Importantly, the method not only functionalizes medicinally important quinoxalin‐2(1H)‐one
A straightforward palladium-catalyzed oxidative C-3 arylation of quinoxalin-2(1H)-ones with arylboronicacids is reported. This protocol is compatible with a wide range of functional groups and allows construction of various biologically important quinoxalin-2(1H)-one backbones.
Direct C3−H amination of quinoxalin‐2(1H)‐ones with azoles has been achieved in a very fast manner. This protocol features broad substrate scope, good yields, and mild reaction conditions.
A F reagent-mediated direct C-H carbamoylation of quinoxalin-2(1H)-ones has been developed. Under roomtemperature, a variety of isocyanides are employed to couple well with quinoxalin-2(1H)-ones affording 42 examples including 30 new compounds. This metal-free mild strategy tolerates a wide range of functional groups and shows environmental friendliness and practicality.