Acetone → 7-hydroxy-2,2-dimethyl-4H-benzo[d][1,3]dioxin-4-one

Participants

Reaction Conditions

Reaction Steps

To a cold mixture of 2,4-dihydroxybenzoic acid (25.9 g, 168.1 mmol), acetone (12.7 g, 218.5 mmol) and DMAP (1.03 g, 8.4 mmol) in 1,2-dimethoxyethane (DME) (96 mL) in an ice bath was added thionyl chloride (26.0 g, 218.5 mml) slowly. Resulting mixture was stirred at 0° C. for 1 h and then at rt for 23 h. Reaction mixture was quenched at 0° C. with saturated NaHCO3 solution (slowly with caution). After 200 mL of saturated NaHCO3 solution was added, NaHCO3 solid was added in small portion to the mixture until pH reaches 7-8. It was diluted with water (200 mL) and extracted with EtOAc (2×200 mL). Organic layers were combined and washed with brine, dried over MgSO4, filtered and concentrated. Crude residue was triturated with CH2Cl2 (100 mL). Solid was collected and dried to provide the title compound (10.4 g). 1H NMR (200 MHz, DMSO-d6): δ (ppm)=7.66 (d, J=7.8 Hz, 1H), 6.59 (d, J=7.8 Hz, 1H), 6.36 (s, 1H), 1.65 (s, 6H).

Provenance & Evidence