Twenty-four derivatives (5) of 4-acyloxy-1-(1, 3-dioxolan-4-ylmethyl) piperidine were synthesized and their spasmolytic activities were examined. Some of them showed remarkable papaverine-like and/or atropine-like activities ; in particular, compounds 5c, 5d, 5e, 5l, and 5p were as active or more active than papaverine. The introduction of lipophilic substituents on the dioxolane moiety increased the papaverine-like activity.