Synthesis of curcumin was first described by Lampe et al. In our laboratory curcumin has been synthesized by condensing vanillin (I) and acetyl acetone (II) in a medium of ethyl acetate using tributylborate as boron complex to avoid Knoevenagel condensation at C-3 of acetyl acetone. Curcumin is isolated from the reaction mixture by acidification and extraction with ethyl acetate. The organic layers are washed until neutral, dried and the solvent is removed. purified by chromatography over silica gel using ether/petroleum ether as the solvent.

The protection of 4-bromo-2-methoxyphenol (I) with ethyl vinyl ether (II) and TsOH in dichloromethane gives the ethoxyethyl ether (III), which is treated with n-BuLi in THF to yield the phenyl lithium compound (IV). The reaction of (IV) with 2H-labeled DMF (V), followed by hydrolysis with HCl, affords the labeled 4-hydroxy-3-methoxybenzaldehyde (VI), which is finally condensed with pentane-2,4-dione (VII) by means of B2O3 and tetrahydroquinoline in DMF.

The protection of 4-bromo-2-methoxyphenol (I) with ethyl vinyl ether (II) and TsOH in dichloromethane gives the ethoxyethyl ether (III), which is treated with n-BuLi in THF to yield the phenyl lithium compound (IV). The reaction of (IV) with 14C-labeled DMF (V), followed by hydrolysis with HCl, affords the labeled 4-hydroxy-3-methoxybenzaldehyde (VI), which is finally condensed with pentane-2,4-dione (VII) by means of B2O3 and tetrahydroquinoline in DMF.