1',5'-dimethylspiro[1,3-dioxolane-2,10'-pyrido[4,3-b]carbazol]-9'(6'H)-one InChI=1/C19H16N2O3/c1-10-12-5-6-20-11(2)13(12)9-14-17-15(21-18(10)14)3-4-16(22)19(17)23-7-8-24-19/h3-6,9,21H,7-8H2,1-2H spiro[1,3-dioxolane-2,10'-[10H]pyrido[4,3-b]carbazol]-9'(6'H)-one, 1',5'-dimethyl-