Protocatechuic Acid → HCID 11524671, compound

Participants

Reaction Steps

Benzyl bromide (1.50 cm3, 2.16 g, 12.6 mmol) was added to a stirred suspension of 3,4-dihydroxybenzoic acid (1.00 g, 6.49 mmol), potassium carbonate (1.97 g, 14.3 mmol) and a catalytic amount of tetrabutylammonium iodide in N,N-dimethylformamide (50 cm3). The suspension was stirred under nitrogen overnight then water (500 cm3) and 5% hydrochloric acid (50 cm3) were added, and the mixture was extracted with diethyl ether (3×100 cm3). The combined extracts were washed with water (3×100 cm3) and brine (100 cm3), then dried (Na2SO4) and evaporated to an orange oil. Flash column chromatography (eluent: 10-20% ethyl acetate in light petroleum) gave first benzyl 3,4-dibenzyloxybenzoate (168 mg, 6%), identical to that prepared above. Further elution then gave benzyl 4-benzyloxy-3-hydroxybenzoate (1.312 g, 60%) as a pale yellow oil. The position of the benzyloxy group was deduced from an n.O.e. observed between the proton at position 5 and the methylene protons of the benzyloxy group at position 4.

Provenance & Evidence