Synthesis
General procedure for the synthesis of 2,4-dimethoxyphenol from 2,4-dimethoxybenzaldehyde: To 0.5 mL of formic acid was added slowly and dropwise a 50 mL methanol solution containing 2,4-dimethoxybenzaldehyde (5.0 g, 30 mmol) and 5 mL of 30% H2O2. The reaction mixture was stirred at room temperature for 20 hours. Upon completion of the reaction, about 45 mL of methanol was evaporated using a rotary evaporator. Subsequently, the remaining solution was subjected to liquid-liquid partitioning with dichloromethane and distilled water. The aqueous phase was further extracted with 3 x 50 mL of dichloromethane. The organic phases were combined, washed with 3 x 50 mL of distilled water, dried over anhydrous sodium sulfate, filtered and the organic solvent was evaporated. The crude product was purified by column chromatography (eluent: chloroform) to afford 2,4-dimethoxyphenol as a light yellow oil (4.33 g, 94% yield).The structure of 2,4-dimethoxyphenol was confirmed by the following characterization data: IR νmax (cm-1, KBr): 3443, 2997, 2939, 2835, 1610, 1512, 1461, 1433, 1374, 1299. 1433, 1374, 1299, 1263, 1228, 1202, 1151, 1116, 1033, 918, 830, 792.1H NMR (300.13 MHz, CDCl3) δ (ppm): 6.75 (d, J = 5.2 Hz), 6.42 (d, J = 1.7 Hz), 6.31 (dd, J = 5.2, 1.7 Hz), 3.79 (s, OCH3), 3.69 (s, OCH3) EIMS m/z (relative abundance): 156 (4, [M+2]+.), 155 (40, [M+2]+.) , 155 (40, [M+1]+.) , 154 (100, [M]+.) , 140 (4), 139 (58), 112 (4), 111 (90), 96 (22), 79 (10), 69 (10), 51 (20).
References
[1] European Journal of Medicinal Chemistry, 2013, vol. 69, p. 798 - 816
[2] Journal of Organic Chemistry, 1984, vol. 49, # 24, p. 4740 - 4741
[3] Organic Letters, 2012, vol. 14, # 11, p. 2806 - 2809
[4] Tetrahedron Letters, 1999, vol. 40, # 15, p. 3037 - 3040
[5] Journal of the Chemical Society, Perkin Transactions 1, 2000, # 5, p. 799 - 811
