ChemInform Abstract: Synthesis and Cycloaddition Reaction of 2a,4,5-Triazabenz(cd)azulene Derivatives.

ChemInform Abstract

The hydrazinoazaazulene (Ia) reacts with triethyl orthoformate (II), producing the triazabenzazulene (IIIa). The corresponding chloro analogue (IIIb) is only obtained as a by-product from (Ib); the main product (IV) is also prepared by ring cleavage of (IIIb) with silica gel. (IIIa) undergoes cycloaddition reaction with dimethyl acetylenedicarboxylate (V), forming the diesters (VI) and (VII). (Mechanism).