A one-pot hypoiodite catalysed oxidative cycloetherification approach to benzoxazoles

Abstract

A practical one-pot hypoiodite catalysed oxidative cyclization approach to synthesize α-ketobenzoxazole derivatives was successfully developed. This operationally simple protocol utilizes easily-accessible starting materials and has a broad substrate scope with excellent yields.

Synthesis of 2-((2-(Benzo[d]oxazol-2-yl)-2H-imidazol-4-yl)amino)-phenols from 2-((5H-1,2,3-Dithiazol-5-ylidene)amino)phenols through Unprecedented Formation of Imidazole Ring from Two Methanimino Groups

“…105–107 °C) [ 36 ]. The 1 H and 13 C NMR spectra were similar to those described in the literature [ 45 ].…”

Sequential, One‐Pot Access to Arylated Benzoquinones/Naphthoquinones from Phenols/Naphthols

“…The reaction between 1‐naphthol ( 1a ) and N , N ‐dimethylaniline ( 2a ) was chosen as the model for optimization studies (Table 1). Recently, our group were interested in developing sequential one‐pot reactions and we conceived that a similar strategy could be employed to construct arylated quinones 9a,9d–9f. Through reference to literature reports, the oxidation of 1‐naphthol ( 1a ) to naphthoquinone ( 1a′ ) was optimized by using meta ‐chloroperoxybenzoic acid ( m ‐CPBA; 2 equiv.)…”

Overview on Recent Approaches towards Synthesis of 2‐Keto‐annulated Oxazole Derivatives

“…The enol‐carbon of intermediate A becomes activated by B resulting in intermediate C . The intramolecular nucleophilic attack of OH group of intermediate C leads to formation of intermediate D and reproduces the catalyst for the catalytic cycle (Scheme ).…”

“…Concerning the reaction mechanism, it is proposed that the reaction sequence started with enolization of compound 46, which is in equilibrium with its enol form intermediate A. Hypoiodite [28].…”