1-Methyl-4-piperidyl-1-(1-carboxycyclopentyl)-3-hydroxy-3-phenylbutyrate gamma-lactone 101834-43-9 2-OXASPIRO(4.4)NONANE-3-ACETIC ACID, 1-OXO-1-PHENYL-, 1-METHYL-4-PIPERIDYL ESTER