Mandelic Acid → Daidzein

Participants

Reaction Conditions

Reaction Steps

Resorcinol (29 mmol) and 4 hydroxyphenyl acetic acid (29 mmol) were dissolved into freshly distilled borontrifluoride etherate (20 mol eq) under nitrogen. The resulting mixture was stirred and heated at 70° C. for overnight. The reaction was monitored by TLC (80% Et2O/Hexane). The resulting mixture was cooled down at room temperature, then N,N-dimthylformamide (46.2 mL) was added dropwise. The mixture was again heated up at 50° C. for 30 minutes, then methanesulphonyl chloride (7 mL in 10 mL DMF) was added dropwise and the resulting mixture was heated at 60-70° C. until LC (80% Et2O/Hexane) shown that the reaction was almost finished, about 10 hours. After cooling down at room temperature, the mixture was poured into 400 mL ice-cold water. The precipitate was filtered. The filtrate was collected and dried. The cure product was recrystallised in 94% ethanol (aq) and gave a quite pure daidzein (3 g) in 44% yield.

Provenance & Evidence