1,3,3-Trimethylbenzoindolinopyranospiran 1,3,3-Trimethylindolinobenzopyrylspiran 1,3,3-Trimethylindolinobenzospiropyran 1485-92-3 NSC206174 Spiro[2H-1-benzopyran-2,2'-[2H]indole], 1',3'-dihydro-1',3',3'-trimethyl- Spiro[2H-1-benzopyran-2,2'-indoline], 1',3',3'-trimethyl-