Abstract: N-substituted cyclopentano[f]-1,2,3,4-tetrahydroisoquinolines of the formula ##SPC1##Wherein R.sub.1 and R.sub.2 represent hydroxy, lower alkoxy, lower alkanoyloxy or aryl-lower alkanoyl groups, R.sub.3 represents hydrogen or a lower alkyl group and R.sub.4 represents a lower alkyl, arylcarbonyl, aryl-lower alkyl, benzhydryl-lower alkyl, lower alkanoyl, aryl-lower alkanoyl, benzhydryl-lower alkanoyl or benzhydrylcarbonyl group, and acid addition salts and quaternary ammonium salts thereof, and pharmaceutical compositions containing one or more of the compounds useful for lowering blood pressure in animals.

Abstract: 2-Alkyl-7,8-cyclopentano[h]-1,2,3,4-tetrahydroisoquinolines of the formula ##SPC1##Wherein R is an aryl-lower alkyl amino group, an aryl-lower alkyl imino group, a diaryl-lower alkyl amino group or a diaryl-lower alkyl imino group, R.sub.1 is hydrogen or a lower alkyl group and R.sub.2 is a lower alkyl group, and acid addition salts and quaternary ammonium salts thereof, and the use of such compounds in pharmaceutical compositions to lower blood pressure in hypertensive animals.

Abstract: 5 OR 1'-Hydroxy-2-alkyl-7,8-cyclopentano[h]-1,2,3,4-tetrahydroisoquinolines and esters of the formulas ##SPC1##Wherein R is a lower alkyl having 1 to 6 carbon atoms, R.sub.1 is hydrogen, a lower alkyl group, an alkanoyl, benzoyl or aralkanoyl group, R.sub.2 is a lower alkyl group and R.sub.3 is hydrogen, benzoyl, an alkanoyl group or an aralkanoyl group, and acid addition salts and quaternary ammonium salts thereof. The compounds are useful in pharmaceutical compositions for lowering blood pressure in animals.Wherein R is a lower alkyl having 1 to 6 carbon atoms, R.sub.1 is hydrogen, a lower alkyl group, an alkaoyl, benzoyl or aralkanoyl group, R.sub.2 is a lower alkyl group and R.sub.3 is hydrogen, benzoyl, an alkanoyl group or an aralkanoyl group, and acid addition salts and quaternary ammonium salts thereof. The compounds are useful in pharmaceutical compositions for lowering blood pressure in animals.