Synthesis of Syringaldehyde from 5-Bromovanillin

To a reflux apparatus add 1 L of methanol and 85.2 g of sodium metal, after all of the sodium has reacted distill the methanol off until the solution becomes a slurry. Start flushing the apparatus with argon and add 214 g of 5-bromovanillin dissolved in 420 mL of dry DMF over the course of 25 minutes. Stirring is important. Dissolve 10,7 g of cuprous chloride in 140ml of DMF and add it to the mixture, stir the mixture at 97°C for 2.5 h. In vacuum distill the DMF off and add the residue to 1 L of 15 % sodium chloride solution, stir at 50°C for 30 minutes. Then cool the solution down to 0°C and acidify the solution with 300 mL of cold conc. HCl with stirring. Continue the stirring for one hour and then filter to obtain the crude syringaldehyde powder, wash with 1 L of water. Extract the syringaldehyde with ethyl acetate by stirring the crude product in hot 1 L of ethyl acetate and then filtering the mixture and evaporating the solvent. Recrystallize in hot ethyl acetate.

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