1-Methyl-4-(2',3'-dihydroxyphenyl)-4-carboxypiperidine-gamma-lactone hydrochloride 7-Hydroxy-1'-methylspiro(benzofuran-3(2H),4'-piperidine)-2-one hydrochloride NU-541 Spiro(benzofuran-3(2H),4'-piperidine)-2-one, 7-hydroxy-1'-methyl-, hydrochloride WG9862000