Ozonization of phenols from Anacardium occidentale (cashew)

Abstract

AbstractThe phenolic lipid components cardanol and cardol, obtained from heat‐processed technical cashew nutshell liquid from Anacardium occidentale, and anacardic acid from the natural product, each containing monoene, diene, and triene constituents, were ozonized. The ozonides were reduced chemically and catalytically to give 8‐(3‐hydroxyphenyl)octanal, 8‐(3,5‐dihydroxyphenyl)octanal, and 8‐(3‐hydroxy‐2‐carboxyphenyl)octanal, respectively, together with formaldehyde, malondialdehyde, butanal, and heptanal in each case. Reduction of the 8‐(3‐hydroxyphenyl)octanal, which was synthesized from 3‐benzyloxybenzaldehyde, gave 3‐octylphenol. Oxidation of the aldehyde with potassium permanganate gave 8‐(3‐hydroxyphenyl)octanoic acid, and reduction with sodium borohydride yielded 8‐(3‐hydroxyphenyl)octanol. For comparison, the trans‐diols of cardanol were prepared by treatment of cardanol with peroxyformic acid and cleaved by periodate oxidation to give an alternative route to 8‐(3‐hydroxyphenyl)octanal but in lower yield. Likewise, the cis‐diols were obtained with potassium permanganate and cleaved without isolation to give the same product in lower yield compared with ozonization.