Ring closure reactionsRing closure reactions O 0130 Bisindoles. Part 38. Synthesis of Some Derivatives of 1H,6H-Indolo[7,6-g]indole. -New derivatives of indoloindole [cf. (III), (VII)] are synthesized by condensation of 1,5-naphthalenedihydrazine with alkyl ketones. Nucleophilic addition of spirofluorenecyclopropene (VIII) to indoloindole (VII) provides the new photochromic spirocyclic system (IX). -(SAMSONIYA, S. A.; TRAPAIDZE, M. V.; MACHAIDZE, N. N.; DUERR, G.; Chem. Heterocycl. Compd. (N. Y.) 38 (2002) 4, 396-399; Javakhishvili State Univ., Tbilisi 380028, Georgia; Eng.) -M. Schroeter 02-041

organic phosphors, phototropic organic phosphors, phototropic (photochromic) substances T 2200 32 -176 Bisindoles. Synthesis of a New Spirocyclic Photochromic System. -A method for the synthesis of (I) is presented. It forms the unstable betaine (II) upon the action of light. -(SAMSONIYA, SH. A.; DUERR, G.; TRAPAIDZE, M. V.; CHKHAIDZE, E. R.; GOGRICHIANI, E. O.; Chem.