Diphosphorus Tetraiodide (P2I4): An Efficient Catalyst for Synthesis of 2-Aryl-1,3-benzazoles via Cyclocondensation of o-Amino/Mercaptan/Hydroxy Anilines with Aryl Acids

Abstract

An efficient and versatile approach for the synthesis of 2-substituted 1,3-benzazoles has been developed via diphosphorus tetraiodide (P2I4) catalyzed condensation reaction of ortho-substituted anilines (-NH2, -SH and -OH) with various aromatic acids to give benzimidazoles, benzothiazoles and benzoxazoles in excellent yields. Additionally, the synthetic approach reported herein has advantages such as mild reaction conditions, broad substrate scopes as well as simple one-pot operation, common for all the three 1,3-benzazoles, which makes this strategy highly attractive.

One-pot, three-component, iron-catalyzed synthesis of benzimidazolesviadomino C–N bond formation

“…3,[6][7][8] There are several known routes to benzimidazole derivatives (Scheme 1). Reaction between o-phenylenediamine and carbonyl compounds such as aldehydes, [9][10][11][12][13] ketones, 14 acids, 15 acyl chlorides, 16 and as well as b-ketoesters, 17,18 or orthoesters, 19,20 or and benzylic including benzyl alcohols, 21 benzyl amines, 22 and toluene derivatives 23 are the main methods for the synthesis of a large number of benzimidazole derivatives. Another important approach is the reaction of 2-aminonitrobenzenes with acids, 24 aldehydes, 25 and activated methyl groups.…”