Hydrochloric Acid → 2,2-dimethyl-3,4-dihydro-2H-1-benzopyran-7-ol

Temperatur

0 °C

A mixture of 7-hydroxy-2,2-dimethylchroman-4-one (500 mg, 2.60 mmol) and HCl (conc. 10 mL) in MeOH (30 mL) was stirred at 0° C. for 10 min, then zinc power (300 mg) was added slowly. After stirring at room temperature for 16 hrs, the solvents were removed under reduced pressure and the mixture was extracted with EtOAc (150×3 mL). The combined organic layers were washed with brine, dried over Na2SO4, filtered and concentrated. The residue was purified by reverse phase column flash (28%-35% MeCN in 0.5% NH4HCO3) to give target product of 2,2-dimethylchroman-7-ol (290 mg, 62%) as a brown yellow solid. LCMS (ESI) m/z: 177.1 [M−H]+; 1H-NMR (500 MHz, CDCl3): δ 6.89 (d, J=8.0 Hz, 1H), 6.34 (dd, J=8.5, 2.5 Hz, 1H), 6.27 (d, J=2.5 Hz, 1H), 4.70 (s, 1H), 2.69 (t, J=13.5, 7.0 Hz, 2H), 1.77 (t, J=13.5, 7.0 Hz, 2H), 1.32 (s, 6H).

1. stirringAfter stirring at room temperature for 16 hrs
2. customthe solvents were removed under reduced pressure
3. extractionthe mixture was extracted with EtOAc (150×3 mL)
4. washThe combined organic layers were washed with brine
5. dry with materialdried over Na2SO4
6. filtrationfiltered
7. concentrationconcentrated
8. customThe residue was purified by reverse phase column flash (28%-35% MeCN in 0.5% NH4HCO3)

ORD-Eintrag

ord-d9fc11a0594140398409073dc59cbdca

Quelldatensatz

uspto-grants-2015_01

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08933236B2