The present invention relates to a chemical compound having the general formula (I):wherein R1 and R2 are, equal or independently, aryl or heteroaryl; and RTA is a 2-1,3-, or 4-1,3- or 5-1,3-thiazole ring with the general Formula (IIa) or a 1,3,4-thiadiazole ring which can also be substituted.The invention also relates to said compound according to formula (I) for use in treating cognative function defects, in particular for use in improving the working memory and/or the short-term memory. Further, the invention relates to processes for preparing compounds according to formula (I).