Dimethylformamide → 2,5-Dimethoxy-3,4,6-trimethylbenzaldehyde

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Reaction Steps

1-Bromo-2,5-dimethoxy-3,4,6-trimethylbenzene from Step 1 (5 g, 19.3 mmol, 1 equiv.) was dissolved in benzene (2×20 mL) and the solvent removed in vacuo to remove residual water. The dry solid was dissolved in toluene (100 mL) and the resulting solution cooled in an ice-water bath. To the colorless solution was added n-BuLi (1.6 M in hexanes, 16 mL, 26.9 mmol, 1.4 equiv.) dropwise over 1 min. After 2 min stirring, the resulting aryllithium species was quenched with DMF (7 mL, 90 mmol, 4.5 equiv.). Following an additional 30 min, excess base was quenched with 1 M aqueous citric acid (20 mL), and the mixture diluted in ethyl acetate (100 mL). The organics were removed, rinsed with brine (30 mL), dried over anhydrous sodium sulfate, filtered, and concentrated in vacuo to give 4.5 g 2,5-dimethoxy-3,4,6-trimethylbenzaldehyde as an orange solid, which was used without further purification. 1H NMR (CDCl3, 400 MHz) 10.5 (s, 1H), 3.79 (s, 3H), 3.63 (s, 3H), 2.55 (s, 3H), 2.31 (s, 3H), 2.23 (s, 3H) ppm.

Provenance & Evidence