Synthesis of 2‐Perfluoroalkylazuleno[2,1‐d]pyrimidin‐4(3H)‐ones via Brønsted Acid‐Mediated Intramolecular Cyclization and Transformation into Pyrimidines

Abstract

AbstractBrønsted acid‐mediated intramolecular cyclization of 2‐amidoazulene derivatives, prepared by the reaction of 1‐cyano‐2‐aminoazulene derivatives with perfluoroalkyl acid anhydrides, resulted in the formation of 2‐perfluoroalkylazuleno[2,1‐d]pyrimidin‐4(3H)‐ones. Heating of these products in phosphoryl chloride led to 4‐chloro‐2‐perfluoroalkylazuleno[2,1‐d]pyrimidines. We also evaluated the reactivity of these pyrimidin‐4(3H)‐ones and pyrimidine derivatives toward the electrophilic and nucleophilic substitution reactions, revealing that a variety of functional groups can be incorporated into these derivatives. The NMR studies, NICS calculations, and single‐crystal X‐ray structure analyses revealed structural features including the bond‐length alternation of the azuleno[2,1‐d]pyrimidin‐4(3H)‐ones and pyrimidine derivatives.