Vanillin → 3-Chloro-4-hydroxy-5-methoxybenzaldehyde

Participants

Reaction Steps

Compound 12 was prepared according to the procedure of Hann et al. (J. Am. Chem. Soc. 1927, 49, 535-7). To a solution of 2.50 g (16.4 mmol) of vanillin in 15 mL of glacial acetic acid was added chlorine gas through a glass tubing over 30 minutes (with a slow gas flow) at 25° C. White solid product was collected by filtration, washed with 50 mL of hexane, and dried in vacuo to give 2.033 g of 12. The acetic acid filtrate was again treated with chlorine gas as above for 30 minutes to give another 0.659 g of 12. A total of 2.691 g (88% yield) of 12 was obtained. The white solids were used in next step without purification. 1H NMR (CDCl3) δ 10.04 (s, 1H, OH), 9.76 (s, 1H, CHO), 7.56 (d, J=1.6 Hz, 1H, Ar), 7.37 (d, J=1.6Hz, 1H, Ar), 3.91 (s, 3H, OMe); 13C NMR (CDCl3) δ 190.5 (C═O), 149.0 (s, 2C), 128.2 (s), 125.6 (d), 120.1 (s), 109.2 (d), 56.3 (q).

Provenance & Evidence