Dimethylformamide → HCID 19737922, Verbindung

To a stirred solution of the 1,3-dibromobenzofuran 11 (10 g, 30.9 mmol) in anhydrous THF (250 mL) at -78° C. under nitrogen was added a 2.5M butyllithium in hexane solution (13.6 mL, 33.9 mmol). The resulting red solution was warmed to -50° C. and held there for 10 min. before anhydrous DMF (2.6 mL, 33.9 mmol) was added dropwise. The resulting rust colored solution was stirred an additional 20 min. at -50° to -40° C. before being quenched with saturated ammonium chloride solution (25 mL). The THF was removed under vacuum and the residue was dissolved in ethyl acetate (EtOAc) and washed sequentially with water, saturated aqueous ammonium chloride solution, water and brine. The organic solution was then dried with magnesium sulfate and decolorized with Norite. The mixture was then filtered and concentrated under vacuum. The residue was triturated with ether/hexane to provide 4.0 g of pale yellow flakes of dibenzofuran 35. The mother liquor was then chromatographed (silica gel, 30% EtOAc in hexanes) to provide an additional 2.1 g of dibenzofuran 35 (total yield: 73%).

1. additionwas added dropwise
2. custombefore being quenched with saturated ammonium chloride solution (25 mL)
3. customThe THF was removed under vacuum
4. dissolutionthe residue was dissolved in ethyl acetate (EtOAc)
5. washwashed sequentially with water, saturated aqueous ammonium chloride solution, water and brine
6. dry with materialThe organic solution was then dried with magnesium sulfate
7. filtrationThe mixture was then filtered
8. concentrationconcentrated under vacuum
9. customThe residue was triturated with ether/hexane

ORD-Eintrag

ord-df680211118d41c6944cbc9ee71965b9

Quelldatensatz

uspto-grants-1993_08

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US05240920