Reaction of α-iminomethylene amino esters with mono- and bidentate nucleophiles: a straightforward route to 2-amino-1H-5-imidazolones

The reaction between α-iminomethylene amino esters with different mono- and bidentate nucleophiles has been studied. It has been shown that the reactions with primary and secondary amines as monodentate nucleophiles afford 2-aminoimidazolones efficiently under very mild conditions. Judicious selection of the primary amines employed can modulate the regioselectivity. Analogous reactions employing bidentate nucleophiles (e.g. amidines) also afford imidazolyl derivatives. The formation of the latter is preferred over the formation of seven-membered heterocycles of the triazepinone type. The optimized methodology in solution described herein should be readily adaptable to use in the solid phase for the parallel synthesis of collections of 2-aminoimidazolone derivatives with a high degree of molecular diversity.