Cyclocondensation of o‐Phenylenediamines with 2‐Oxo‐ethanimidothioates: A Novel Synthesis of 2‐Amino‐3‐(het)aryl‐quinoxalines

Abstract

2‐Amino‐3‐(het)aryl‐quinoxalines were synthesized by the cyclization reaction between 2‐oxo‐ethanimidothioates and o‐phenylenediamine in the presence of acid catalyst p‐TSA in toluene at 80 °C. The products were obtained in 58–84 % yields. The required substrates 2‐oxo‐ethanimidothioates were synthesized by the condensation reaction between α‐oxodithioester and amine in the presence of sodium hydride in DMF followed treatment with methyl iodide.

Synthesis, characterization and antibacterial evaluation of N‐(2‐Morpholinoethyl)‐3‐phenylquinoxalin‐2‐amine derivatives

“…All chemicals and solvents were obtained from Sigma Aldrich and Merck without any purification. The methyl α ‐oxodithioates were prepared according to the earlier reported method [28]. Reactions were continuously monitored by thin layer chromatography using commercially available precoated plates (MERCK 60F254, 0.25 mm thickness) and visualized under UV lamp.…”

“…Additional methods include the oxidative coupling of 2-nitroanilines with vicinal diols, α-hydroxy ketones [12], catechol [14], ketones and epoxides [15]. Recently we have reported the synthesis of quinoxalines by the cyclization of o-phen ylenediamine with α-oxodithioester [16]. Meanwhile, morpholine is used as an important pharmacophore group in medicinal chemistry.…”

A panoramic view on synthetic applications of α-oxothioamides: a highly regioselective synthesis of 2-acyl-4-(het)arylthiazoles and thioethers

“…In continuation of our efforts in organic synthesis [38][39][40][41][42][43][44] we have recently reported the synthesis of quinoxalines, 45,46 thiazoles 47 and benzoxazoles 45 from a-ketodithioesters. In this direction, we have recently reported the synthesis of a-ketothioamides and explored their applications for the synthesis of 3,5-bis(acyl)-1,2,4-thiadiazoles.…”

Condensation of Amines with S-Methyl Thiouronium Salts: Another Entry for the Synthesis of Amidines

“…We have recently developed -oxodithio esters, 30,31 2oxoethanimidothioates, 32 2-oxo-2-(amino)ethanedithioates, 33 carbimidothioates, 34 xanthate esters, 35 and carbamimidothioates 36,37 as potential key intermediates in organic synthesis. In this direction, we report a potential application of S-methyl thiouronium salts in the synthesis of N,N,N′-trisubstituted amidines.…”