Sodium hydride → Methyl (2s)-2-ethyl-2,3-dihydro-1-benzofuran-2-carboxylate

Temperatur

110 °C

To a solution of the product from Step 3 (4.0 g, 20 mmol) in 1:4 DMF/toluene (100 mL) was added 60% NaH in mineral oil (1.76 g, 44 mmol) in 3 portions. The reaction mixture was stirred at 110° C. under N2 for 4 hrs. The reaction was cooled to room temperature and poured into cold water (100 mL). The aqueous layer was washed with hexane (50 mL), acidified with 2 N aqueous HCl and extracted with ethyl acetate (3×50 mL). The extracts were washed with brine (50 mL), dried and concentrated. The residue was dissolved in 7:1 benzene/MeOH (80 mL) and treated with TMSCHN2 (1M in hexane) until gas evolution ceased. The reaction was concentrated and the residue was chromatographed on silica gel eluting with 85:15 hexane:ethylacetate to give the title compound

1. temperatureThe reaction was cooled to room temperature
2. washThe aqueous layer was washed with hexane (50 mL)
3. extractionextracted with ethyl acetate (3×50 mL)
4. washThe extracts were washed with brine (50 mL)
5. customdried
6. concentrationconcentrated
7. dissolutionThe residue was dissolved in 7:1 benzene/MeOH (80 mL)
8. additiontreated with TMSCHN2 (1M in hexane) until gas evolution
9. concentrationThe reaction was concentrated
10. customthe residue was chromatographed on silica gel eluting with 85:15 hexane

ORD-Eintrag

ord-137c58feff304dd9af7138ea28d4c564

Quelldatensatz

uspto-grants-2009_12

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US07629372B2