A unified convergent strategy has been developed for the facile synthesis of a series of novel fused azines
bearing a phenothiazine moiety based on the aza-Michael addition reaction of an enaminone derivative to a variety
of different heterocyclic amines under microwave irradiation conditions. The results of this study revealed
that new methods are required to allow for the simple and efficient analysis of the fused azine products of this reaction
other than single-crystal X-ray crystallography. With this in mind, 1H–15N HMBC experiments were used in
the current study to allow for the unambiguous structural characterization of the fused azine products. These results
provided further support in favor of the proposed structures and allowed for the resolution of several discrepancies
reported in the literature regarding the structural characterization of these compounds.
Keywords: Microwave irradiations, pyrazolo[1, 5-a]pyrimidines, triazolo[1, 5-a]pyrimidine, pyrimido[1, 2-a]benzimidazole, 1H-15N HMBC.
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