Synthesis of 4,4'-dihydroxyazobenzeneand 4'-Dihydroxyphenylazo-2-naphthol from Diazotised aniline and Anthocyanins from Delonix regia flower
Lawrence Mark Leonard Ogboji
Department of Chemistry, University of Agriculture, Makurdi, Nigeria
Oaikhena Zekeri Esezobor *
Fakultät für Chemie und Pharmazie, University of Regensburg, Germany
Mulu Emmanuel Khan
Department of Chemistry, University of Agriculture, Makurdi, Nigeria
John Ogbaji Igoli
Department of Chemistry, University of Agriculture, Makurdi, Nigeria
*Author to whom correspondence should be addressed.
Abstract
The synthesis of 4-phenylazo phenol by coupling anthocyanins extracted from Delonix regia flowers with diazotised aniline is presented in this paper. Also reported here is the reduction of 4-phenylazo phenol to yield 4-aminophenol and coupling of 4-aminophenol to phenol and 2-naphthol which yielded 4,4'-dihydroxyazobenzene and 4'-hydroxyphenylazo-2-naphthol, respectively. The structures of the compounds were confirmed by 1H- and 13C-NMR spectroscopy after purification by column chromatography on silica gel.
Keywords: Delonix regia, anthocyanins, 4-phenylazo phenol, azo dyes