2,4-Dihydro-2,2'-dioxospiro(benz[c,d]indole-5(1H),3'-indoline)-3-carboxylic acid 73972-38-0 NSC203299 Spiro(benz[c,d]indole-5(1H),3'-indoline)-3-carboxylic acid, 2,4-dihydro-2,2'-dioxo- Spiro[benz[cd]indole-5(1H),3'-[3H]indole]-3-carboxylic acid, 1',2,2',4-tetrahydro-2,2'-dioxo-