Gan et al. Compounds and have been converted to corresponding quinones and by oxidation with bis trifluoroacetoxy iodobenzene BTIB. For instance, the total syntheses of various biologically important short-chain ubiquinones were accomplished via oxidative demethylation using CAN in good yield by Keinan et al. The Journal of Organic Chemistry , 78 11 , They used a range of oxidants such as cobalt, nickel, copper and vanadyl with different salen type ligands. Zora et al.
Synthesis of 1,4-benzoquinones from phenols Several techniques have been reported for the oxidation of phenols to benzoquinones.
Blake, and Christopher J. First total synthesis and phytotoxic activity of Streptomyces sp. Suma, M. Journal of Natural Products , 82 7 ,
The CAN oxidation lies at the heart of an elegant synthesis of symmetrical 2,5-disubstituted 1,4-benzoquinones from 1,4-dimethoxybenzene via a palladium catalysed double Negishi coupling Scheme Also both nitric acid and silver oxide required strong acidic media which the acid labile functional group could not tolerate. Tetrahedron Letters , 57 16 , Canuto, Alyne R. DOI: Compounds and have been converted to corresponding quinones and by oxidation with bis trifluoroacetoxy iodobenzene BTIB.
Bremer, Mark S. Polymer supported methyltrioxorhenium systems were used as heterogeneous catalysts. Oxidation of hydroquinones to 1,4-benzoquinones One of the earliest synthetic protocol of 1,4-benzoquinones from hydroquinone was disclosed by Vliet more than 70 years ago.
Moody and co-workers reported a microwave-mediated Claisen rearrangement followed by phenol oxidation to yield many naturally occurring 1,4-benzoquinones from readily available precursors.
The Teuber reaction, which uses Fremy's salt [potassium nitrodisulfonate, KSO3 2NO] as oxidizing agent has been the earliest reported and widely used method. Wang et al. Sheena Mohan, S. Kitson, and Christopher J. Synthesis and characterization of 2- n-alkylamino -1,4-napthoquinone: Molecular structures of ethyl and hexyl derivatives.
In a two step procedure, Shi et al. Canuto, Alyne R. Teuber reaction is especially useful for the synthesis of heterocyclic quinones, where other oxidizing agents fail. For instance, the total syntheses of various biologically important short-chain ubiquinones were accomplished via oxidative demethylation using CAN in good yield by Keinan et al. Nawrat, William Lewis, Christopher J. This elegant transformation of 2-chloro-1,3-diketone is depicted in Scheme