6,7-Dimethoxy-3-(piperazin-1-yl)isoquinolin-1-amine is an intermediate for the synthesis of Terazosin-md (T105020), an analog of Terazosin (T105000), which is an α1-adrenergic receptor antagonist alleviating organ damage in studies done on rodent models of stroke and sepsis and has potential to be used for treatment for diseases.