2‐(2‐Amino‐4,5‐dimethoxyphenyl)ethylamine 2‐(3,4‐Dimethoxyphenyl)‐ethylamine 2‐(4,5‐Dimethoxy‐2‐nitrophenyl)ethylamine 99m‐Technetium complexes Animalia Biodistribution Chemical shift Conformations Density functional calculations Density functional theory Derivatives Functional groups Maleimide/phthalimide derivatives Methoxy chemical shifts Methoxy groups Phthalimide derivatives Preparation Substituted dimethoxyphenethylamines Substitution reactions animal experiment article brain controlled study drug distribution drug structure drug synthesis electrophoresis female intracerebral drug administration isotope labeling