1,3-Dihydroisobenzofuran → 1,3-Dihydro-2-benzofuran-5-amine

Temperatur

70 °C

To a solution of 1,3-dihydro-isobenzofuran (83.2 mmol) in sulfuric acid (75 mL), cooled in an ice bath, add a solution of potassium nitrate (83.2 mmol) in sulfuric acid (25 mL) dropwise. After stirring for 30 min, pour the reaction mixture over ice and collect the resulting precipitate on a glass frit. Wash the precipitate with water (200 mL) and dry under vacuum. Dissolve the precipitate in ethanol (250 mL) and add tin chloride dihydrate (273.6 mmol). After heating at 70° C. for 2 h, dilute with water (200 mL), cool to room temperature, and neutralize the reaction with 5 N NaOH. Extract the mixture with ethyl acetate (3×200 mL) and dry the organic portion over sodium sulfate. Remove the solvent in vacuo to afford the title compound as a tan solid. 1H NMR (CDCl3, 400 MHz) δ 3.50 (bs, 2H), 5.02 (s, 4H), 6.56 (d, J=2.4 Hz, 1H), 6.60 (dd, J=2.4, 8.0 Hz, 1 H), 7.01 (d, J=8.0 Hz, 1H).

1. additionpour the reaction mixture over ice
2. customcollect the resulting precipitate on a glass frit
3. washWash the precipitate with water (200 mL)
4. customdry under vacuum
5. dissolutionDissolve the precipitate in ethanol (250 mL)
6. temperaturecool to room temperature
7. extractionExtract the mixture with ethyl acetate (3×200 mL)
8. dry with materialdry the organic portion over sodium sulfate
9. customRemove the solvent in vacuo

ORD-Eintrag

ord-970a0db53e6c41b8a4f7ce1dc7f3b967

Quelldatensatz

uspto-grants-2010_08

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07786108B2