3,5-Bis(1-piperidinylmethyl)-1-isobutyl-4-phenyl-4-piperidinecarboxylic acid ethyl ester 4-Piperidinecarboxylic acid, 3,5-bis(1-piperidinylmethyl)-1-(2-methylpropyl)-4-phenyl-, ethyl ester 70575-41-6