On September 11, 1941Bockmühl and Ehrhart filed an application for a patent for a synthetic substance they called Hoechst 10820 or polamidon and whose structure had no relation to morphine or the opioid alkaloids (Bockmühl and Ehrhart, 1949). Although chemically unlike morphineor heroin, methadone also acts on the opioid receptorsand thus produces many of the same effects.