Abstract: Compounds of the formula (I) ##STR1## optically active isomers thereof, and/or pharmaceutically acceptable acid addition salts thereof are disclosed, wherein R.sup.1 is selected from the group consisting of hydrogen, methyl, ethyl, n-propyl, n-butyl, 2-hydroxyethyl, 3-hydroxypropyl and 4-hydroxybutyl, and wherein R is selected from the group consisting of ##STR2## in which R.sup.2, R.sup.3 R.sup.4 and R.sup.5 are the same or different and are each independently selected from the group consisting of hydrogen and methyl. Pharmaceutical preparations employing such compounds and method of using such compounds are also disclosed.