Synthesis of two new heteroaromatic beta-carboline-fused pentacycles. Observation of a new intercalating agent.

Five-step synthetic routes of two new polyfused heterocycles: indazolo[3,2-a]-beta-carboline (3) and benzo[4',5'][1,2,3]triazino[6,1-a]-beta-carbolinium salt (10) applying Pd(0)-catalyzed cross-coupling reaction have been elaborated.

Synthesis of Azinylvinylpyridazines: A General Note on the Isomerization of Hetaryldienamines.

Azinyldienamines underwent Diels Alder reaction of inverse electron demand with 1,2,4,5-tetrazine diester to give azinylvinylpyridazines. Comparison of the products obtained from mono-, di-, and triazinyldienamines revealed that, in some cases, isomerization of the olefinic side chain occurred which can be rationalized by the tautomeric conditions of the intermediates bearing these azine moieties. These experimental findings supported also by semiempirical calculations suggest the importance of the influence of the hetaryl group in such isomerizations.