Separation of New Naphthoxazole Derivatives of Lapachol by High-Speed Counter-Current Chromatography

<div><p>This work describes the use of high-speed counter-current chromatography as an efficient and economic method in the separation and purification of new naphthoxazolic heterocyclic derivatives from lapachol (<b>1</b>), a naturally occurring naphtoquinone from different species of <i>Tabebuia</i>. A series of naphthoxazoles was obtained by nucleophilic condensation of lapachol (<b>1</b>) with aromatic aldehydes in ammonium medium. Each reaction led to the formation of two main products, derivatives from β-xyloidone, and the naphthoxazoles with the isoprenyl side chain of lapachol (<b>1</b>). Reaction products were purified by counter-current chromatography, using hexane–acetonitrile–methanol (2:2:1, v/v/v) as a non-aqueous solvent system.</p>