Efficient synthetic access to novel N-(Pyrimidinyl)-N-(1H-benzo[d]imidazolyl)amines in an aqueous medium

This study describes a simple, efficient, and environmentally benign procedure for synthesizing a novel series of 13 N-(pyrimidinyl)-N-(1H-benzo[d]imidazolyl)amines, from the cyclocondensation reaction of (benzo[d]imidazolyl)guanidine with 4-alkoxy-4-alkyl(aryl/heteroaryl)-1,1,1-trifluoroalk-3-en-2-ones or 2,2,2-trifluoro-1-(2-methoxycyclohexen-1-en-1-yl)ethanone. The (benzo[d]imidazolyl)guanidine precursor was earlier obtained from the reactions of cyanoguanidine with o-phenylenediamine. The trifluoroacetylated enol ethers were synthesized from the trifluoroacetylation reaction of enol ethers or acetals with trifluoroacetic anhydride. The main reactions were performed in pure refluxing water as the solvent (1-24 h), without catalysts, and the corresponding new N-(pyrimidinyl)-N-(1H-benzo[d]imidazolyl)amines were obtained at good to excellent yields (60-90 %). Subsequently, N-alkylation reactions were performed to obtain tertiary amines and to increase the solubility of the amines. [GRAPHICS] .