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

Temperature

0 °C

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).

1. customResulting mixture
2. waitat rt for 23 h
3. customReaction mixture
4. customwas quenched at 0° C. with saturated NaHCO3 solution (slowly with caution)
5. additionAfter 200 mL of saturated NaHCO3 solution was added
6. additionNaHCO3 solid was added in small portion to the mixture until pH
7. additionIt was diluted with water (200 mL)
8. extractionextracted with EtOAc (2×200 mL)
9. washwashed with brine
10. dry with materialdried over MgSO4
11. filtrationfiltered
12. concentrationconcentrated
13. customCrude residue was triturated with CH2Cl2 (100 mL)
14. customSolid was collected
15. customdried

ORD record

ord-1f638f9d589746fe9475d69c095bfb64

Source dataset

uspto-grants-2012_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08324405B2