Acetic Anhydride → Ethanone, 1-(2,3-dihydro-6-benzofuranyl)- (9CI)

Temperature

-78 °C

A solution of bromo(2,3-dihydro-1-benzofuran-6-yl)magnesium (prepared from 6-bromo-2,3-dihydro-benzofuran (2.50 g, 12.56 mmol) and Mg (0.336 g, 13.8 mmol)) in THF (10 mL) was dropwise added to a solution of acetic anhydride (2.40 mL, 25.4 mmol) in Et2O (10 mL) held at −78° C. The reaction mixture was stirred at −78° C. for 1 h before the temperature was allowed to reach −10° C. over a period of 1 h. The reaction mixture was quenched by the addition of NH4Cl (aq, saturated, 20 mL) and the resulting mixture was extracted twice with Et2O (2×10 mL). The organic extracts were pooled, washed with NaOH (aq, 5%, 10 mL) and brine (10 mL), dried over MgSO4 and concentrated under reduced pressure. The residue was purified by preparative HPLC using a gradient of 20-50% MeCN in a 0.1M ammonium acetate buffer as eluent. Freeze-drying of the pure fractions gave the desired product.

1. customheld at −78° C
2. waitto reach −10° C. over a period of 1 h
3. customThe reaction mixture was quenched by the addition of NH4Cl (aq, saturated, 20 mL)
4. extractionthe resulting mixture was extracted twice with Et2O (2×10 mL)
5. washwashed with NaOH (aq, 5%, 10 mL) and brine (10 mL)
6. dry with materialdried over MgSO4
7. concentrationconcentrated under reduced pressure
8. customThe residue was purified by preparative HPLC
9. customFreeze-drying of the pure fractions

ORD record

ord-d46191ba43c0479f8899e17b98136e75

Source dataset

uspto-grants-2011_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07893048B2