Base-catalyzed multicomponent access to quinoxalin-2-thiones from o-phenylenediamines, aryl ketones and sulfur

Abstract

3-Arylquinoxaline-2-thiones were conveniently synthesized via three-component oxidative condensation of acetophenones with o-phenylenediamines and sulfur in DMSO in the presence of piperidine as a catalyst. The products could be readily isolated...

Three-Component Reaction between 3-Acetylcoumarins, Amines, and Elemental Sulfur: A Designed Approach to 3-Amino-4H-thieno[3,2-c]coumarins

“…Interestingly, Nguyen’s group developed significant methods toward the synthesis of heterocyclic compounds using alkyl aryl ketones and elemental sulfur . In 2018, they reported the synthesis of 2,4-diarylthiophenes via aniline acid–base conjugate pairs catalyzed self-condensation of two acetophenone molecules with one sulfur atom .…”

Sulfur-Promoted Oxidative Condensation of Chalcones with Unsubstituted Cyanoacetamide in DMSO: Access to 3-Cyanopyrid-2-ones

“…To circumvent this limit, using elemental sulfur instead of oxygen could be a promising solution. Indeed, with good compatibility with phenol and aniline functions, even upon heating, sulfur was found to be an excellent to promote oxidative hetero-functionalization with these types of nucleophiles. Moreover, due to its solid state and low volatility, sulfur could be readily weighed and added to the reaction mixture with the desired quantity.…”

Sodium sulfide-promoted regiodefined redox condensation of o-nitroanilines with aryl ketones to benzo[a]phenazines and quinoxalines

“…Indeed, when o -nitroanilines bearing a 6-methyl, 4-methyl, 5-methoxy, 4-halo (F, Cl, and Br) or 4-trifluoromethyl substituent were allowed to react with acetophenone 4a , practically only one regioisomer quinoxaline 5q–5w was formed. 10 As in the previous cases with α-tetralones 2a , quinoxalines 5q–5w were generated by the connection between the amino group of the starting o -nitroanilines and the carbonyl group of acetophenone 2a . These results underline a unique virtue of redox condensation in comparison to non-redox condensation.…”