methyl 1-(2-(tert-butyldimethylsiloxy)ethyl)-6-methoxy-2-methyl-4,7-dioxo-4,7-dihydro-1H-indole-3-carboxylate

ethyl 6-methoxy-2-[(4-methoxybenzyloxy)methyl]-1-methyl-4,7-dioxo-4,7-dihydro-1H-indole-3-carboxylate

tert-butyl 6-methoxy-1-(3-methoxyphenyl)-2-methyl-4,7-dioxo-4,7-dihydro-1H-indole-3-carboxylate

ethyl 2-(allyloxymethyl)-6-methoxy-1-methyl-4,7-dioxo-4,7-dihydro-1H-indole-3-carboxylate

dimethyl 6-methoxy-1-(4-methoxybenzyl)-4,7-dioxo-4,7-dihydro-1H-indole-2,3-dicarboxylate