1-Methyl-4-phenyl-4-beta,beta-dimethylacroyloxypiperidine hydrochloride 3-Methylcrotonic acid 2-methyl-4-phenyl-4-piperidyl ester hydrochloride Crotonic acid, 3-methyl-, 1-methyl-4-phenyl-4-piperidyl ester, hydrochloride GQ5783000 NU-857