The synthesis of 2-hydroxymethyl derivatives of phenols

Abstract

2-Hydroxymethylphenols have been prepared in good yield by reduction with sodium borohydride of the precursor aldehydes, obtained regiospecifically from reaction of phenols with paraformaldehyde in toluene containing stannic chloride and tri-n-butylamine. By contrast, reaction of phenols with either paraformaldehyde under anhydrous conditions or with aqueous formaldehyde results in formation of both the hydroxymethyl and the bishydroxymethyl derivatives. Cyclic acetals of the precursor aldehydes are readily accessible.

2-[(4-Bromophenylimino)methyl]-5-pentadecylphenol

“…2-Hydroxy-4-pentadecylbenzaldehyde [12] was prepared from cardanol (3-pentadecylphenol, contained, e.g., in Cashew nut shell liquid) by formylation, using a standard procedure [12]. The title compound was obtained in good yield (81%) by refluxing compound 1 with an equimolar amount of 4-bromoaniline in 1,4-dioxane for 5 hours.…”

5-Pentadecyl-2-((p-tolylimino)methyl)phenol

“…2-Hydroxy-4-pentadecylbenzaldehyde [7] was prepared from cardanol (3-pentadecylphenol, contained, e.g., in Cashew nut shell liquid (CNSL)) by formylation, using a standard procedure [7]. The title compound was obtained in low yield (42%) by refluxing compound 2 with an equimolar amount of 4-amino-1-methyl-aniline in 1,4-dioxane for 5 hours.…”

4-[(2-Hydroxy-4-pentadecylbenzylidene)amino]-1,5-dimethyl-2-phenyl-1,2-dihydro-3H-pyrazol-3-one

“…It is a mixture of saturated and unsaturated (mono-, di-, and tri-) compounds. Cardanol (1) is a phenolic compound with a C 15 aliphatic chain in the meta position, obtained from cashew nut shell liquid (CNSL) and then formylation of hydrogenated cardanol using Reimer-Tiemann reaction following a standard procedure [8] Figure 2. …”