Huperzine a analogs as acetylcholinesterase inhibitors

摘要

An acetylcholinesterase inhibitor is provided of the general formula (I): ##STR1## wherein R.sub.1 is H, (C.sub.1 -C.sub.8)alkyl or halo; R. sub.2 is H or (C.sub.1 -C.sub.8)alkyl; R.sub.3 and R.sub.4 are individually H, (C.sub.1 -C.sub.8)alkyl, NO.sub.2, hydroxy or halo; R.sub. 5 and R.sub.6 are individually H, (C.sub.1 -C.sub.8)akyl, aryl or aralkyl; R.sub.7 is H, halo or (C.sub.1 -C.sub.8)alkyl, R.sub.8 is halo or (C.sub. 1 -C.sub.8)alkyl; R.sub.9 is absent or is H; and the bonds represented by- -are individually absent or, together with the adjacent bond, form the unit C═C, with the proviso that if both of the bonds represented by-- are present, R.sub.3 and R.sub.4 cannot both be H unless R.sub.7 or R.sub. 8 is halo; and the pharmaceutically acceptable salts thereof.