1-Oxa-3-azaspiro(4.5)decane-3-carboxylic acid, 8-methyl-2-oxo-, 2-dimethylaminoethyl ester, fumarate, (E)- 72017-31-3 Dimethylaminoethyl 8-methyl-2-oxo-1-oxa-3-azaspiro(4.5)decane-3-carboxylate fumarate, (E)-