A Green Route for the One‐Pot Synthesis of 1,2‐Disubstituted Benzimidazoles Using Iron(III) Phosphate under Solventless Conditions

Abstract

1,2-Disubstituted benzimidazoles are selectively synthesized in high yields under extremely mild conditions via the condensation of o-phenylenediamine derivatives with aldehyde derivatives using catalytic amount of iron(III) phosphate under solvent-free conditions. The use of readily available iron(III) phosphate as a reusable and recyclable catalyst makes this process quite simple, convenient, and environment-friendly.

Water-Soluble Phosphated Graphene: Preparation, Characterization, Catalytic Reactivity, and Adsorption Property

“…The crude product was obtained after evaporation of the solvent under reduced pressure. Next, the residue was recrystallized with EtOH. , …”

“… a Reaction conditions: o -phenylenediamine (1 mmol), aldehyde (2.5 mmol), EtOH solvent (5 mL), and PGO catalyst (10 mg) at room temperature. b Products were characterized by comparing their spectroscopic FT-IR and melting point data with those reported in the literature. , c Refer to the reaction yields for the first run with the catalyst (PGO). …”

“… b Products were characterized by comparing their spectroscopic FT-IR and melting point data with those reported in the literature. , …”

A new catalyst for the synthesis of 2-substituted perimidines catalysed by FePO4

“…Recently, the use of an inorganic solid acid in organic synthesis has become more popular [8][9][10][11][12]. In addition to the cases mentioned above, FePO 4 is an inexpensive, safe and available reagent [13] that has also been employed for the selective oxidation of CH 4 to CH 3 OH [14] and benzene to phenol [15], one-pot synthesis of dihydropyrimidinones and thiones [16], one-pot three component synthesis of 2,4,5-trisubstituted imidazoles [17], synthesis of 1,2,4,5-tetraarylated imidazoles [18], acetylation of alcohols and phenols with acetic anhydride [19], synthesis of bis(indolyl)methanes [20], synthesis of 1,2-disubstituted benzimidazoles [21] and synthesis of 2-disubstituted benzimidazoles [22]. In addition, a part of our programme is aimed at developing selective and environmental friendly methodologies for the preparation of fine chemicals [17][18][19][20][21]; due to the versatile biological properties of perimidines and as a continuation of our studies on the synthesis of heterocyclic compounds, we report a clean and simple synthetic method for the preparation of perimidines using FePO 4 as an efficient catalyst, which was employed as green catalyst for the reaction between 1,8diaminonaphthalene and aromatic aldehydes at ambient temperature.…”

Three‐Component Synthesis of 3‐Aminoalkylindoles using Iron(III) Phosphate

“…In this regards, iron (III) phosphate has been used and new applications of this catalyst explored Therefore a variety of 3‐aminoalkylated indoles have been prepared via combination of aromatic aldehydes, N ‐methyl aniline and indole in the presence of catalytic amounts of iron (III) phosphate (Scheme ).…”