tically acceptable acid addition salts thereof, wherein R2 is a member selected from the group consisting of hydrogen and lower alkyl;X is a member selected from the group consisting of hydroxyloweralkyl, aminocarbonyl, and (lower alkyl)aminocarbonyl; m is the integer 1 or 2; R3, R4 and R5 are each independently selected from the group consisting of hydrogen, hydroxy, lower alkyl, lower alkyloxy,