4'-Methoxy-[1,1'-biphenyl]-4-methanamine-d3 is labelled 4'-Methoxy-[1,1'-biphenyl]-4-methanamine (M261345) which is used to prepare biphenylmethyl urea derivatves as MCH-R1 antagonists for reatment of obesity. It is also used to synthesize the Pseudomonas aeruginosa virulence factor LasB inhibitors.