PROCESS TO OBTAIN SYNTHETIC AND SEMI-SYNTHETIC LIGNAN DERIVATIVES, THEIR ANTIPARASITIC ACTIVITIES AND CORRESPONDING PHARMACEUTICAL FORMULATIONS, INCLUDING THE THERAPEUTIC METHOD USING SAID LIGNAN FOR THE TREATMENT OF PARASITOSIS 

The invention refers to a process to obtain synthetic and semi-synthetic derivatives of lignans, especially dibenzylbutyrolactonic, tetrahydrofuranic, aryltetralynic, furofuranic and dibenzocyclooctanic lignans obtained by means of partial synthesis and/or full synthesis or also by isolation from plant extracts. It refers to a process to obtain synthetic and semi-synthetic derivatives of (-)-cubebin, such as: (-)-O-acetylcubebin; (-)-O-methylcubebin; (-)-O-N,N-(dimethylamino-ethyl)-cubebin; (-)-hinokinin; (-)-6,6’-dinitroinokinine; (-)-O-benzylcubebin; (-)-6,6'-diaminoinokinin, (-)-6,6’-dinitroinokinin, as well as to obtain dibenzocyclooctanic lignans from dibenzylbutyrolactoinic lignans by means of structural modifications in the positions 7, 7’, 8, 8’, 9’ and in the aromatic rings (introduction and/or substitution of functional groups such as: -OH, -CO2H, -CO2CH3, -NO2, -NH2, -OCH3, -OAc, -SO2CH3, -SO2NH2, prenyl and halogens). The invention also refers to a therapeutic method, since the substances described are used in the manufacture of medicine that presents antiparasitic activity.