3.4- Dimethoxybenzaldehyde Veratraldehyde

H.57) Benzaldehyde, 3,4-dimethoxy-, 3,4-dimethoxybenzaldehyde, veratraldehyde, methylvanillin, protocatechualdehyde dimethyl ether 1120-14-9] FEMA 3109... 

Dimethoxybenzaldehye or 2,4-Dimethoxybenzaldehyde or Veratraldehyde. Equimolar quantities of phosphorus oxychloride (1 mole = 153 g) and N-methylformanilide (1 mole = 135 g) are placed in a 1 liter, three necked flask and allowed to stand for 45 min. To this mixture is added, over 70 min with stirring, and cooling at 25° 1 mole of 1,4-dimethoxybenzene (to get... 

Dimethoxybenzaldehyde and veratraldehyde use the same procedure, which follows. It should be noted, that the poor yields of these two products can be improved considerably by using 0.2 mole scale instead of 1 mole, as described above. You will have to change the reagent quantities to 0.2 mole also, the reaction times will remain the same as will the temps. 

After the 70 min addition, at 25° with good stirring, is complete, the cooling bath is removed and the mixture is heated, with stirring, at 70° for 18 hours. It is then poured into water and ice and the product is extracted with ether. The extract is shaken with sodium bicarbonate solution, dried and distilled under 21.0 mm of vacuo. Yields veratraldehyde, 12.5 g (38%), 2,5-dimethoxybenzaldehyde, 16%. For a better yield see CA, 44, 6831, b. 

Bromo-3,4-dimethoxybenzaldehyde was purchased from the Aldrich Chemical Company, Inc. (Milwaukee) or readily prepared by bromination of veratraldehyde (Aldrich Chemical Company, Inc. or Tokyo Kasei).4... 

A. 6-Bramo-S,4-dimethoxybenzaldehyde cyclohexylimine (1). A 2-L, threenecked flask is equipped with a Dean-Stark trap, reflux condenser, magnetic stirrer, and nitrogen inlet. The vessel is purged with nitrogen and charged with 40,0 g (0.16 mol) of 6-bromo-3,4-dimethoxybenzaldehyde (6-bromo-veratraldehyde) (Note 1), 22.4 mL (0.20 mol) of cyclohexylamine (Note 2), and 800 nt of toluene. The mixture is refluxed for 16 hr (Note 3). The solution is cooled to room temperature and the solvent is removed on a rotary evaporator. The residual crystalline mass is recrystallized from a 3 1 hexane-methylene chloride mixture (1.5 L) to provide 48.4-51.4 g of the imlne 1 as white crystals In two crops (mp 172-172.5°C)2 (Note 4). 

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