Abstract: A compound having the formula, ##STR1## or any of its enantiomers or any mixture thereof, or a pharmaceutically acceptable salt thereof;whereinR is hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkylalkyl or 2-hydroxyethyl; andR.sup.4 isphenyl which may be substituted one or more times with substituents selected from the group consisting of halogen, CF.sub.3, CN, alkoxy, cycloalkoxy, alkyl, cycloalkyl, alkenyl, alkynyl, amino, nitro, heteroaryl and aryl;3,4-methylenedioxyphenyl;benzyl which may be substituted one or more times with substituents selected from the group consisting of halogen, CF.sub.3, CN, alkoxy, cycloalkoxy, alkyl, cycloalkyl, alkenyl, alkynyl, amino, nitro, heteroaryl and aryl;heteroaryl which may be substituted one or more times with substituents selected from the group consisting of halogen, CF.sub.