Synthesis of 3′,4′‐Diaryl‐4′H‐spiro[indoline‐3,5′‐[1′,2′,4′]oxadiazol]‐2‐ones via DMAP‐catalyzed Domino Reactions and Their Antibacterial Activity

Abstract

A convenient and metal‐free DMAP‐catalyzed domino reaction of isatins, arylamines and hydroximoyl chlorides has been developed to achieve 1,3‐dipolar cycloaddition of imines into aryl nitrile oxides at ambient temperature. In this one‐pot transformation, a 1,2,4‐oxadiazole skeleton was efficiently formed. This methodology needs no extra additives and features wide substrate scope, good functional group tolerance and mild reaction conditions. A plausible mechanism for this process was proposed. Moreover, the antibacterial activities of the products were evaluated towards Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae using the Broth microdilution method.

Catalyst‐free straightforward synthesis of 3‐cyano‐3‐arylamino‐2‐oxindoles through hydrocyanation with benzoyl cyanide

“…Melting points were observed in an electrothermal melting point apparatus (X‐5, Beijing Tech Instrument Co. Ltd, China). 3‐(Arylimino)indolin‐2‐ones were synthesized according to literature procedure …”

Spiro‐2‐oxindoles via 1,3‐dipolar cycloadditions. A decade update

“…Mild reaction conditions were experienced, and no extra additives such as metal ions of catalyst were needed. Wide substrate scope and good functional group tolerance allowed to obtain 22 examples of spiro(2‐oxindolo)‐1,2,4‐oxadiazole cycloadducts with 78–95 % yield, Scheme 48 [137] . The antibacterial activities of these compounds were screened in vitro against two gram negative and two gram positive bacterial strains ( Staphylococcus epidermidis , Staphylococcus aureus , Escherichia coli and Klebsiella pneumoniae ).…”

Regioselective mono-aza-Michael additions of divinyl ketones with 3-(arylimino)indolin-2-ones: Synthesis of N-enone-functionalized 3-(arylimino)indolin-2-ones

“…High-resolution mass spectra (HRMS) (ESI) were obtained with a Bruker Daltonics APEX II 47e and Orbitrap Elite mass spectrometer. Divinyl ketones 21,22 and 3-(arylimino)indolin-2-ones 6,23 were synthesized according to literature procedures.…”