Hydrogen Peroxide → 3-(3-Hydroxypropyl)-4,5-dimethoxybenzoic acid

Participants

Reaction Conditions

Reaction Steps

To a solution of 3-allyl-4,5-dimethoxybenzoic acid methyl ester (Example 30, Step 1, 10.2 g, 43.2 mmol) in THF (100 mL) at 0° C. was added BH3.SMe2 (4.10 mL, 43.2 mmol). After 45 min the reaction mixture was warmed to 23° C. After stirring for 1.2 h the reaction was cooled to 0° C. and slowly treated with 3.0 N NaOH (39 mL) followed 10 min later by addition of H2O2 (30 weight %, 60 mL). Following the addition, the mixture was allowed to reach 23° C., then heated to reflux for 2 h. After cooling to room temperature, the mixture was partitioned between brine (400 mL) and EtOAc (500 mL). The aqueous layer was separated and extracted with EtOAc (400 mL). The organic layer was discarded and the aqueous was adjusted to pH 5 by addition of 1.0 N HCl then the product was extracted with EtOAc (2×500 mL). The organic layer was dried over MgSO4 and then concentrated in vacuo to give 3-(3-hydroxypropyl)-4,5-dimethoxybenzoic acid (9.24 g, 89%) of the desired alcohol, which was used without further purification. ESMS: m/z 239.3 [M−H].

Provenance & Evidence