An efficient one-pot synthesis of 3-glyoxylic acids of electron-deficient substituted azaindoles by ionic liquid imidazolium chloroaluminate-promoted Friedel–Crafts acylation

Iron Powder Promoted Regio-Selective Friedel-Crafts Acylation of Indole Under Solvent-Free Conditions

“…Various synthetic methods are reported in the literature for 3-substituted indoles [3][4][5][6][7][8][9][10][11][12][13] . The common method to prepare 3-acyl indoles is Friedel-Crafts reaction under acidic conditions, which resulting in the side reactions caused from high nucleophilic nature of indole [6][7][8][9][10][11][12][13] . Hence, several efforts have also been made to reduce the competing side reactions [10][11][12] .…”

“…The common method to prepare 3-acyl indoles is Friedel-Crafts reaction under acidic conditions, which resulting in the side reactions caused from high nucleophilic nature of indole [6][7][8][9][10][11][12][13] . Hence, several efforts have also been made to reduce the competing side reactions [10][11][12] . On the other hand, the development of suitable catalysts for the facile synthesis of 3-acyl indoles without NH-protection has attracted much attention.…”

Acylation of salicylamide to 5-acetylsalicylamide using ionic liquids as dual catalyst and solvent

“…Ionic liquids have potential applications in catalytic and organic reactions as possible replacement for conventional molecular solvents and catalysts [11]. For example, 1-ethyl-3-methylimidazolium chloroaluminate ionic liquid showed good catalytic activity in the synthesis of 3,6-dibenzoylacenaphthene by acylation of acenaphthene with benzoyl chloride [12] and in the synthesis of substituted azaindole-3-glyoxylic acids via one-pot acylation/ hydrolysis reaction procedure [13]. 1-Butyl-3-methylimidazolium chloroaluminate ionic liquid was used as both catalyst and solvent in the acylation of anthracene with oxalyl chloride to 1,2-aceanthrylenedione [14].…”

“…Pyridinium based ionic liquids efficiently catalyzed the acylations of aromatic compounds with acetic anhydride under relatively mild conditions [15]. In ionic liquids, 1-alkyl-3-methylimidazolium and N-alkylpyridinium are recognized as two important cations [12][13][14]16]. Polynuclear anions with Lewis acidity show good catalytic activity for Friedel-Crafts acylation reactions [17,18].…”

Regioselective Friedel–Crafts Acylation of Indoles Catalysed by Zinc Oxide in an Ionic Liquid

“…[3][4][5][6][7][8][9][10][11][12][13][14][15][16] A common method to prepare 3-acylindoles is Friedel-Crafts reaction under acidic conditions, which always results in side reactions as a result of the high nucleophilic nature of indole. [7][8][9][10] Hence, several efforts have been made to reduce this competing side reactions. [10][11][12] Also, the development of suitable catalysts for the facile synthesis of 3-acylindoles without NH-protection has attracted much attention.…”