Hydrochloric Acid → 2,3-Dihydro-1-benzofuran-7-carbaldehyde

2,3-Dihydrobenzofuran-7-carboxylic acid (820 mg, 5 mmol) was dissolved in THF (10 mL). To the solution was added TEA (0.7 mL, 5 mmol) and methylchloroformate (0.43 mL, 5 mmol). The solution was stirred for 0.5 hour. The white precipitates were removed by filtration, the filtrate was added to a solution of NaBH4 (437 mg, 12.5 mmol) in H2O (5 mL). The resulting solution was stirred overnight. The reaction mixture was neutralized with 2 M aqueous HCl solution and then extracted with EtOAc. The organic layer was washed with brine, dried over anhydrous Na2SO4 and concentrated in vacuo. The crude alcohol was dissolved in DCM. To the solution was added PCC (1.83 g, 7.5 mmol). The mixture was stirred for 2 hours at room temperature and diluted with diethyl ether, then ether layers were decanted. Combined organic layer was filtered though a layer of Celite®. The filtrate was concentrated to give crude product. The crude was purified from column with 10% EtOAc/hexane to afford 450 mg of 2,3-dihydrobenzofuran-7-carbaldehyde as a slightly yellow solid. HPLC 4.3 min.

1. customThe white precipitates
2. customwere removed by filtration
3. stirringThe resulting solution was stirred overnight
4. extractionextracted with EtOAc
5. washThe organic layer was washed with brine
6. dry with materialdried over anhydrous Na2SO4
7. concentrationconcentrated in vacuo
8. dissolutionThe crude alcohol was dissolved in DCM
9. stirringThe mixture was stirred for 2 hours at room temperature
10. customether layers were decanted
11. filtrationCombined organic layer was filtered though a layer of Celite®
12. concentrationThe filtrate was concentrated
13. customto give crude product
14. customThe crude was purified from column with 10% EtOAc/hexane

ORD record

ord-109f1ede575d4dd8b40aacbef7397876

Source dataset

uspto-grants-2013_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08440706B2