Pyrazino(2',3'-3,4)pyrido(1,2-a) indole derivatives

摘要

Herein is disclosed pyrazino[2',3'-3,4]pyrido[1,2-a]indole derivatives, therapeutically acceptable acid addition salts thereof, processes for their preparation, methods of using the derivatives and pharmaceutical compositions. The derivatives are useful for treating hypertension in a mammal. The derivatives have the formulain which R¹ is hydrogen, halogen, lower alkyl, lower alkoxy or trifluoromethyl; R² is hydrogen or alkyl having one to three carbon atoms; and R³ and R⁴ each independently is hydrogen, lower alkyl, lower alkenyl, lower alkynyl, cyclo(lower)alkyl, lower alkanoyl, hydroxy(lower)alkyl, lower alkoxycarbonyl-(lower)alkyl, phenyl(lower)alkyl or phenoxy(lower)alkyl.