(4R,5R)-(+)-5-ethyl-1-(3-hydroxy-4-methoxyphenethyl)-2-oxo-4-piperidineacetic acid ethyl ester

(4R,5R)-(+)-1-(3-benzyloxy-4-methoxyphenethyl)-5-ethyl-2-oxo-4-piperidineacetic acid ethyl ester

(2R,3R)-9-benzyloxy-2-ethoxycarbonylmethyl-3-ethyl-1,2,3,4,6,7-hexahydro-10-methoxybenzoquinolizinium chloride