A compound of the formula ##STR1## wherein R.sub.1 is H or loweralkyl; R.sub.2 is H, loweralkyl, phenyl or substituted phenyl; R is C.sub.3 -C.sub.20 alkyl, phenyl alkyl or substituted phenyl alkyl; R.sub.3 is H or ##STR2## where X is a straight or branched chain alkylene group of 3 to 4 carbon atoms, and R.sub.4 and R.sub.5 are the same or different members of the group consisting of H or loweralkyl; or R.sub.4 and R.sub.5 taken together form a 6- or 6- member heterocyclic ring and containing no more than one additional heterocyclic atom, with or without .alpha.-loweralkyl substituents, and the acid addition salts thereof. The compounds of this invention are useful as analgesics, tranquilizers, sedative-hypnotics and anti-glaucoma agents.