Summary The synthesis and antispasmotic properties of twenty-one esters are described. Variation of the acid portion of these esters to include unsaturated and partially saturated derivatives of naphthalene, indene, 9-&lkyIfluorene, anthracene, xanthene, thioxanthene, acridine and phenanthrene in some instances causes pronounced changes in pharmacological properties. Of this series, P-diethylaminoethyl xanthene-9-carboxylate ...