Hydrochloric Acid → 4-Bromocatechol

Temperature

0 °C

4-Bromoveratrole (30 g, 0.138 mol) was placed in a three-neck reaction flask and cooled in an ice bath. Boron tribromide, as described Bhatt et al., Synthesis, 249, (1968) the description of which is incorporated by reference herein, (1.0M in CH2Cl2, 0.2 mol) was slowly introduced through a dropping funnel. After the addition was complete, the reaction mixture was refluxed overnight (20 h). The solution was chilled to 0° C. and water was added slowly. The residue was hydrolyzed with a minimum amount of 10% NaOH(aq). The resulting solution was acidified with hydrochloric acid and extracted with ether. The extracts were washed with H2O and brine, then dried over anhydrous MgSO4 and concentrated in vacuo to afford compound 7 (24 g, 92%). The product was used in the next step without purification (only one spot by TLC). 1H-NMR (CDCl3) δ7.02 (d, 1H, Jmeta =2.26 Hz), 6.92 (dd, Jortho =8.45 Hz, Jmeta =2.26 Hz), 6.74 (d, Jortho =8.45 Hz).

1. temperaturecooled in an ice bath
2. customBhatt et al., Synthesis, 249, (1968) the description of which
3. additionwas slowly introduced through a dropping funnel
4. additionAfter the addition
5. temperaturethe reaction mixture was refluxed overnight (20 h)
6. extractionextracted with ether
7. washThe extracts were washed with H2O and brine
8. dry with materialdried over anhydrous MgSO4
9. concentrationconcentrated in vacuo

ORD record

ord-4ffe9e6dafaa4d3f98287a0513f97e50

Source dataset

uspto-grants-1993_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05254726