816441-27-7Relevant academic research and scientific papers
Synthesis of ortho-Azophenols by Formal Dehydrogenative Coupling of Phenols and Hydrazines or Hydrazides
Esguerra, Kenneth Virgel N.,Lumb, Jean-Philip
supporting information, p. 8596 - 8600 (2017/06/30)
Azophenols are important chromophores and reagents in organic synthesis, with applications as pigments and molecular switches. Here, we describe a catalytic aerobic process that couples phenols and hydrazines or hydrazides for their synthesis. The key aromatic C?N bond is formed by condensation between the hydrazine or hydrazide and an ortho-quinone, which triggers a redox-isomerization to install the azo-functionality. Notable features include rapid access to highly functionalized azophenols with a range of electronic configurations, including “push–pull” systems, conditions that employ simple, unactivated substrates, occurrence at room temperature using an earth-abundant and commercially available copper catalyst, and production of water as the only stoichiometric byproduct.
