Tetrahydro-beta-carbolines

A compound of the formula (I) ##STR125## wherein:

• R.sub.1 is hydrogen or C.sub.1 -C.sub.3 alkyl;
• R.sub.2 is hydrogen or C.sub.1 -C.sub.6 alkyl;
• R.sub.3 is hydrogen or C.sub.1 -C.sub.3 alkyl;
• R.sub.4 is C.sub.5 -C.sub.8 cycloalkyl, substituted C.sub.5 -C.sub.8 cycloalkyl, C.sub.5 -C.sub.8 cycloalkenyl, substituted C.sub.5 -C.sub.8 cycloalkenyl;
• A is selected from the group consisting of ##STR126## wherein R.sub.6 and R.sub.7 are, independently, hydrogen, C.sub.1 -C.sub.6 alkyl, C.sub.2 -C.sub.6 alkenyl, halo, halo(C.sub.1 -C.sub.6)alkyl, halo (C.sub.2 -C.sub.6)alkenyl, COR.sub.5, C.sub.1 -C.sub.10 alkanoyl, CO.sub.2 R.sub.5, (C.sub.1 -C.sub.6 alkyl).sub.m amino, NO.sub.2, --SR.sub.5, or OR.sub.5 ;
• each R.sub.5 is independently hydrogen or C.sub.1 -C.sub.4 alkyl;
• R.sub.5' is C.sub.1 -C.sub.4 alkyl;
• R.sub.8 is selected from the group consisting of an R.sub.6 group, substituted C.sub.3 -C.sub.8 cycloalkyl, C.sub.3 -C.sub.8 cycloalkyl, C.sub.3 -C.sub.8 cycloalkyl-(C.sub.1 -C.sub.3)alkyl, C.sub.5 -C.sub.8 cycloalkenyl, substituted C.sub.5 -C.sub.8 cycloalkenyl, C.sub.5 -C.sub.8 cycloalkenyl-(C.sub.1 -C.sub.3)alkyl, C.sub.7 -C.sub.16 arylalkyl;
• or
• m is 1 or 2;
• provided that when A is of formula IV;
• R.sub.6 and R.sub.7 together with the carbon atoms of group A form a 5- to 8-member carbon ring;
• or
• a pharmaceutically acceptable salt or solvate thereof.