A number of tetrahydrofuran analogues of 2'-methylspiro [1-azabicyclo [2.2. 2] octane-3, 4'- [1, 3] dioxolane](1) have been prepared with the aim to obtain information about the relative importance of each of the oxygens in 1 for efficacy and for selectivity. In addition, the dimethyl and deamethyl doguea of 1 &re prepared. The new compounds were compared to cis-and trans-1 with regard to their ability to displace (-)-[3H]-3-quinuclidinyl benzilate ((-)-[ ...