| abstract |
The specification discloses novel tetracyclic compounds of the formula: wherein R1 is hydrogen or C1-C3 alkyl, R2 is C1-C3 alkyl, Y1 is hydrogen or halogen, X1 is a divalent radical selected from the group consisting of -O-, -S-, -N(R3)- and -CO- and R3 is hydrogen or C1-C3 alkyl, and the pharmaceutically acceptable salts thereof, which are useful as antidepressants and can be produced by various methods. |