1-Oxa-3-azaspiro(4.5)decane-3-carboxylic acid, 7,8-dimethyl-2-oxo-, 2-(dimethylamino)ethyl ester, fumarate 5498-60-2 Dimethylaminoethyl 7,8-dimethyl-2-oxo-1-oxa-3-azaspiro(4.5)decane-3-carboxylate fumarate