A facile route to multi-functionalization of methyl gallate: pivotal synthons for mesomorphic materials

The preparation of mono-, di- and trisubstituted gallic derivatives is described using either 1-bromododecane or 12-bromo-1-dodecanol. After saponification of the methyl ester bearing the dodecanol groups, subsequent functionalization with methacryloyl chloride provides the hybrid methacrylate esters/anhydride species. Selective cleavage of the anhydride function gives rise to the corresponding acids, which have been further functionalized to the imine derivative 15 by condensation with 4-[imino-4-(toluyl)]phenol. This reaction is made possible using the acidic form of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (EDC·HCl) and dimethylaminopyridine (DMAP). Selective hydrolysis of the imine function with a HCl-treated silica provides the targeted aniline in excellent yield.