Fused pyrimidine derivatives R 0515 Synthesis of Derivatives of a New Heterocyclic Systems -7-Thia-5,8,11-triazaindeno[1,2-c]fluorene. -(DOTSENKO, V. V.; KRIVOKOLYSKO, S. G.; LITVINOV, V. P.; Chem. Heterocycl. Compd. (N. Y.) 43 (2007) 4, 519-520; "ChemEx" Lab., East. Ukr. State Univ., Lugansk 91034, Ukraine; Eng.) -C. Cyrus 52-159