The present invention provides a novel compound represented by the formula (I): wherein R1 and R2 are as defined in the specification, or a salt thereof, which is useful as a reagent (radiotracer) for VAChT mapping and the like, and can be used for positron emission tomography (PET), and a production method of the compound. Moreover, the present invention provides a diagnostic reagent for diagnosing cholinergic neurodegenerative disorders (e.g., Alzheimer's disease, memory disorder, learning disorder, schizophrenia, cognitive dysfunction, hyperactivity disorder, anxiety neurosis, depression, analgia, Parkinson's disease and the like) and the like, which contains the aforementioned compound.