Abstract: A compound selected from the group consisting of a compound of the formula ##STR1## wherein R.sub.1 is thiazol-2-yl optionally substituted by 1 or 2 alkyl of 1 to 3 carbon atoms optionally substituted by one or more fluorine or --COOAlk, Alk is alkyl of 1 to 3 carbon atoms, R.sub.2 and R.sub.3 are individually selected from the group consisting of hydrogen, alkyl of 1 to 3 carbon atoms and alkenyl of 2 to 5 carbon atoms or R.sub.2 and R.sub.3 together form alkylene of 3 to 5 carbon atoms, X is oxygen or sulfur and R.sub.4 is alkyl of 1 to 3 carbon atoms and their non-toxic, pharmaceutically acceptable acid addition salts having minor tranquillizing activity and useful for the treatment of obesity and cognitive impairment.