2-(PIPERIDIN-4-YL, PYRIDIN-4-YL UND TETRAHYDROPYRIDIN-4-YL)-BENZOFURAN-7-CARBAMAT DERIVATE, IHRE HERSTELLUNG UND VERWENDUNG ALS ACETYLCHOLINESTERASE INHIBITOREN

2-(piperidin-4-yl, pyridin-4-yl and tetrahydropyridin-4-yl)benzofuran-7-ol and carbamate derivatives of the formula I wherein R1 is hydrogen, loweralkyl, arylloweralkyl, CONHR5 or CONR6R7 R2 is hydrogen, cyano, CH2NR8R9, CONHR5 or CONR6R7; R3 is where R10 is hydrogen, loweralkyl, arylloweralkyl, CONHR5, CONR6R7, acyl, acyloxyloweralkyl or acyloxyarylloweralkyl; R4 is hydrogen, halogen, loweralkyl or loweralkoxy; R5 is hydrogen, loweralkyl or arylloweralkyl; R6 is loweralkyl or arylloweralkyl; R7 is loweralkyl or arylloweralkyl; R8 is hydrogen, loweralkyl, arylloweralkyl or acyl; R9 is hydrogen, loweralkyl or arylloweralkyl; R11 is loweralkyl, aryl or arylloweralkyl; with the proviso that if R1 is hydrogen or loweralkyl, R2 cannot be hydrogen; or a pharmaceutically acceptable acid addition salt thereof, or where applicable, an optical or geometric isomer or racemic mixture thereof, which are useful as acetylcholinesterase inhibitors and as such may be useful for the treatment of Alzheimer's disease and other senile dementias.