The invention provides compounds of formula (I): ##STR1## or a physiologically acceptable salt, solvate or metabolically labile ester thereof wherein R.sup.1 represents a hydrogen atom or a halogen atom or a group selected from C.sub.1-6 alkyl, C.sub.2-6 alkenyl, fluoroC.sub.1-6 alkyl, C.sub.1-6 alkoxy, --CHO, --CO.sub.2 H or --COR.sup.2 ; Ar represents optionally substituted phenyl Het represents the group ##STR2## A represents ##STR3## The compounds may be used in the treatment or prophylaxis of hypertension and diseases associated with cognitive disorders.
                            本发明提供的化合物具有以下式子(I)的结构:##STR1## 或其生理上可接受的盐、溶剂或代谢不稳定的酯,其中R.sup.1代表氢原子或卤原子或C.sub.1-6烷基、C.sub.2-6烯基、
氟代C.sub.1-6烷基、C.sub.1-6烷氧基、--CHO、--CO.sub.2 H或--COR.sup.2中选择的基团;Ar代表可选取的取代苯基;Het代表以下基团:##STR2## A代表以下基团:##STR3## 这些化合物可用于治疗或预防高血压和与认知障碍相关的疾病。