In a benzodiazepine derivative and a method of producing the derivative, isatoic anhydride or 5-chloroisatoic anhydride is reacted with amino acid ester hydrochloride for conducting a simple cyclization to obtain a produce with a low percentage of by-product directly without requiring the complicated separation and purification processes of column chromatography, and a chlorine-containing structure of the structure can improve the lipo-solubility and chlorine ion permeability and allow a functional group of a radioisotope to be modified to maximize the effects of the pharmacological properties such as the sedative, anticonvulsant and anti-spasmodic effects on the central nervous system or the benzodiazepine derivative can be used as a contrast agent of the system with excellent effects on applications.