ethyl 2,6,6-trimethylcyclohexa-2,4-diene-1-carboxylate, ethyl rac-3-amino-3-phenyl-propionate hydrochloride, 2,6,6-trimethyl-2,4-cyclohexadiene-1-carboxylic acid ethyl ester, ethyl 2,6,6-trimethyl-2,4-cyclohexadiene-1-carboxylate, 3-amino-3-phenyl-propionic acid ethyl ester hydrochloride, 2,6,6-trimethyl-1-ethoxycarbonyl-2,4-cyclohexadiene