Heteropolyacids as Green and Reusable Catalysts for the Synthesis of 3,1,5-Benzoxadiazepines

Abstract

Synthesis of 3,1,5-benzoxadiazepines from the condensation of o-phenylenediamine (o-PDA) and acyl chlorides in the presence of a catalytic amount of various heteropolyacids (HPAs) is reported.

Recent developments in use of heteropolyacids, their salts and polyoxometalates in organic synthesis

“…Recently the result of a study on the use of three type of heteropolyacids including Preyssler, H 14 the type of HPA, temperature and reaction times on the yield of reactions have also been studied (Scheme 21) [67]. O 40 ] have been used for multi-component synthesis of 4-arylaminoquinazolines 24 from the reaction of 2-aminobenzamide, orthoesters and substituted anilines.…”

Synthetic Approaches to 2-Arylbenzimidazoles: A Review

“…The former required strongly acidic conditions and sometimes high reaction temperatures while the later method required the use of a stoichiometric oxidant for dehydration. In addition 2-arylbenzimidazoles were also synthesized by replacing aryl acids with aryl chlorides [60][61][62][63][64][65][66][67][68][69][70][71]. Efficient one-pot syntheses of 2-arylbenzimidazoles starting from 2-nitroaniline have been also reported [191][192][193][194][195][196].…”

Heteropolyacides as green and reusable catalysts for the synthesis of [3,4-<i>b</i>][1,3,4] thiadiazines

“…Heteropolyacids (HPAs) are well defined molecular clusters that are remarkable for their molecular and electronic structural diversity and their significance is quite diverse in many areas, e.g., catalysis, medicine, and materials science [20,21]. HPAs are complex proton acid that incorporate polyoxometalate anions (heteropolyanions) having metal-oxygen octahedra as the basic structural units and catalysis by them is a field of increasing importance [22][23][24][25][26][27][28][29][30]. Heteropolyacids as solid acid catalysts are green with respect to corrosiveness, safety, quantity of waste, and separ ability and it is well known that the use of heteropolyacid catalysts for organic synthesis reactions can give a lot of benefits.…”