Novel derivatives of imidazopyridinylbenzeneamines and novel derivatives of benzothiazolylbenzeneamines are disclosed that offer improved behavior when used as imaging agents for positron emission tomography of beta-amyloids. Also disclosed is a palladium-catalyzed reaction scheme under microwave conditions for aryl thioethers in general that provides a high ratio of substitution relative to reduction and can be used for the imidazopyridinylbenzeneamine derivatives as well as other compounds of related structure.