A straightforward one-pot multicomponent synthesis of polysubstituted pyrroles

Abstract

Polysubstituted pyrroles were efficiently synthesized in moderate yields by a one-pot multicomponent reaction starting from primary amines, ethyl glyoxalate and 2-bromoacetophenones in the presence of pyridine in refluxing acetonitrile. This methodology was utilized to synthesize a highly substituted benz[g]indole.

Efficient, Three-Component Synthesis of Pyrrole Derivatives Catalyzed by Iodobenzene and Oxone

“…The protocol was applicable to various ranges of amines and it was noteworthy that benzylamines and phenylethylamines reacted more smoothly than anilines to form product in higher yields ( [10][11][12]. Substitutions on phenyl ring of nitrostyrenes had no effect on reactivity and both electron-donating and electron-withdrawing groups afforded the good yields.…”

“…New methodologies for pyrrole synthesis include intramolecular cyclization, [5][6][7] transition-metal catalyzation, [8][9][10][11] and multi-component reactions. [12][13][14][15] All these methods are suffering from drawbacks of tedious workups, use of toxic or expensive transition metals, and unavailability of the starting materials. Therefore, simple method to synthesize pyrrole derivatives under mild reaction conditions is still desirable.…”

Transition metal-free one-pot synthesis of nitrogen-containing heterocycles

“…Lin et al [50] [50]. Tetrasubstituted pyrroles 42 can be synthesized from a green one-pot reaction of arylglyoxal hydrates 40, β-dicarbonyl compounds 41 with ammonium acetate and hydrazine hydrate in water under ultrasonic irradiation (Scheme 14) [51].…”

Diversity Oriented Syntheses of Conventional Heterocycles by Smart Multi Component Reactions (MCRs) of the Last Decade

“…Further syntheses are a highly diastereoselective 3CR from aldehyde + aminomalonate + nitro-alkene to form 2,3,4,5-tetrasubstituted pyrrolidines [ 37 ], a chiral ruthenium porphyrin-catalyzed 3CR with chiral azomethine ylides [ 38 ], 4CRs of aldimines + acyl chlorides + alkynes + CO [ 39 ], and a reaction of alkyne + p -tolylsulfonylmethyl isocyanide (TosMIC) [ 40 ]. Two 3CRs with aniline + glyoxylate + bromobenzophenone [ 41 ] and diazoketone + nitroalkene + amine [ 42 ] have been performed. An extensive and critical review on the use of MCRs to synthesize pyrrole compounds has been published [ 43 ].…”