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Current Organic Synthesis


ISSN (Print): 1570-1794
ISSN (Online): 1875-6271

Convergent Synthesis Strategy of Novel Fused Azines: 1H-15N HMBC NMR as a Tool for Assertion of the Site Selectivity of Aza-Michael Addition Reaction

Author(s): Tamer S. Saleh, Ahmed E. M. Mekky and Abdullah S. Al-Bogami

Volume 13, Issue 2, 2016

Page: [278 - 290] Pages: 13

DOI: 10.2174/1570179412666150914201114

Price: $65


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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