Abstract: The present invention relates to a pharmaceutical composition comprising as active ingredient a compound of the Formula I ##STR1## wherein R.sup.1 stands for straight or branched chain alkyl comprising 1 to 8 carbon atoms; phenyl alkyl having 7 to 10 carbon atoms; phenyl; or cycloalkyl comprising 3 to 8 carbon atoms;R.sup.2 stands for straight or branched chain alkyl comprising 1 to 8 carbon atoms; alkyl comprising 1 to 8 carbon atoms substituted by halogen, hydroxy, alkoxy having 1 to 4 carbon atoms or by one or two phenyl groups; phenyl; or cycloalkyl having 3 to 8 carbon atoms,with the proviso that groups R.sup.1 and R.sup.2 together contain at least three carbon atoms. The invention also relates to a process for the preparation of compounds of the Formula I by methods known per se.

Abstract: A method of treating a learning deficiency is disclosed wherein a patient in need of stimulating learning ability is treated with a therapeutically effective amount of a compound of the Formula (I) ##STR1## wherein R.sup.1 is C.sub.1 to C.sub.8 straight or branched chain alkyl, C.sub.7 to C.sub.10 phenylalkyl, phenyl, or C.sub.3 to C.sub.8 cycloalkyl; andR.sup.2 is C.sub.1 to C.sub.8 straight or branched chain alkyl, unsubstituted or substituted by halogen, hydroxy, C.sub.1 to C.sub.4 alkoxy or by 1 or 2 phenyl groups; or is C.sub.3 to C.sub.8 cycloalkyl;with the proviso that R.sup.1 and R.sup.2 together contain at least 3 carbon atoms; or a pharmaceutically acceptable salt thereof.