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

Temperature

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 sodium hydroxide. Extract the mixture with ethyl acetate (3×200 mL) and dry the organics over sodium sulfate. Remove solvent to afford the title compound as a tan solid. H 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, 1H), 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 organics over sodium sulfate

ORD record

ord-eab5484e478e4b6ab2eae14b21097fca

Source dataset

uspto-grants-2010_07

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07749992B2