| 摘要 |
The present invention relates to compounds of the formula I, <CHEM> where X is O, S, NH, N-loweralkyl, or N-arylloweralkyl; Y is hydrogen, fluorine, chlorine, bromine, nitro, loweralkyl, loweralkoxy, or triloweralkylsilyl; R1 is loweralkyl, halogen-substituted loweralkyl, aryl, arylloweralkyl, cycloalkyl, heteroaryl or heteroarylloweralkyl; R2 is hydrogen, loweralkyl or arylloweralkyl; R3 is loweralkyl or arylloweralkyl; R4 is hydrogen, loweralkyl, loweralkenyl, loweralkynyl, arylloweralkyl, formyl, loweralkylcarbonyl, arylloweralkylcarbonyl or loweralkoxycarbonyl; R5 is hydrogen or loweralkyl; and m is 0 or 1, with the proviso that when m is 0, R1 may also be hydrogen, and a process for their preparation. The compounds of the invention are useful for alleviating various memory dysfunctions characterized by a cholinergic deficit such as Alzheimer's disease. |
