6-Bromobenzylisovanillin is an intermediate in the synthesis of 3,8-Dihydroxy-9-methoxy-6H-Dibenzo[b,d]pyran-6-one (D455545) which has been used in anti-wrinkle agents and is known as a collagen production promoter, MMP-1 production inhibitor and elastase activity inhibitor containing urolithin.
Under nitrogen protection, 2-bromo-5-hydroxy-4-methoxybenzaldehyde (8.70 mmol) was dissolved in 87 mL (0.1 M) of N,N-dimethylformamide (DMF) and cooled to 0 °C. Potassium carbonate (13.1 mmol, 1.8 g) and benzyl bromide (10.4 mmol, 1.77 g) were then added sequentially. The reaction mixture was slowly warmed to 25 °C and the reaction was stirred at this temperature for 5 hours. Upon completion of the reaction, the mixture was poured into 100 mL of aqueous ammonium chloride solution to quench the reaction. The reaction mixture was extracted with ethyl acetate (3 x 30 mL) and the organic layers were combined. The organic layer was washed with saturated saline (10 mL × 2), dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography to afford 2-bromo-4-methoxy-5-benzyloxybenzaldehyde (5-(benzyloxy)-2-bromo-4-methoxybenzaldehyde) 2.73 g (8.53 mmol, 98% yield).
[1] Patent: KR101492960, 2015, B1. Location in patent: Paragraph 0092-0094
[2] Tetrahedron, 2006, vol. 62, # 51, p. 12098 - 12107
[3] Journal of Medicinal Chemistry, 2003, vol. 46, # 8, p. 1289 - 1292
[4] Patent: US2006/257337, 2006, A1. Location in patent: Page/Page column 16-17
[5] Patent: WO2016/29214, 2016, A1. Location in patent: Page/Page column 145