1'-BOC-1,2-DIHYDRO-2-OXO-SPIRO[3H-INDOLE-3,4'-PIPERIDINE]

tert-butyl 2-oxospiro[indoline-3.4-piperidine]-1-carboxylate

tert-butyl 2-oxo-1,2-dihydrospiro[indole-3,4'- piperidine]-1'-carboxylate

1,1-DiMethylethyl 1,2-dihydro-2-oxospiro[3H-indole-3,4'-piperidine]-1'-carboxylate

1,1-DiMethylethyl 2-oxo-1,2-dihydro-1'H-spiro[indole-3,4'-piperidine]-1'-carboxylate

1,2-DIHYDRO-2-OXO-SPIRO[3H-INDOLE-3,4'-PIPERIDINE]-1'-CARBOXYLIC ACID 1,1-DIMETHYLETHYL ESTER