1,3-Dipolar Cycloaddition in a Series of 7-Oxoalkyl-1,3,7-triazapyrenium Salts. -A series of new 7-substituted triazapyrenium salts (III) is synthesized, which undergo 1,3-dipolar cycloaddition reactions with chalcones furnishing previously unknown pyrrolotriazapyrenes [cf. (VIII)]. -(BOROVLEV*, I. V.; DEMIDOV, O. P.; PISARENKO, S. V.; NEMYKINA, O. A.; SAIGAKOVA, N. A.; Chem. Heterocycl.