Ammonium Chloride → 5-Bromo-2,3-dihydro-1-benzofuran

5,7-Dibromo-2,3-dihydrobenzo[b]furan (see WO 02/070020) (3.0 g) in diethyl ether was cooled to −78° C. under argon atmosphere, and thereto was added dropwise n-butyl lithium (2.44 M hexane solution, 5.09 ml). The mixture was stirred at the same temperature for 30 minutes, and poured into a saturated aqueous ammonium chloride solution. The mixture was extracted with diethyl ether, and dried over magnesium sulfate. The solvent was evaporated under reduced pressure to give 5-bromo-2,3-dihydrobenzo[b]furan (2.0 g) as pale yellow crystals, which was used in the subsequent step without further purification. (2) The above 5-bromo-2,3-dihydrobenzo[b]furan and thiophene-2-boronic acid were treated in a manner similar to Reference Example 20-(1) to give the desired 2-(2,3-dihydro-5-benzo[b]furanyl)thiophene as pale yellow crystals. APCI-Mass m/Z 203 (M+H).

1. extractionThe mixture was extracted with diethyl ether
2. dry with materialdried over magnesium sulfate
3. customThe solvent was evaporated under reduced pressure

ORD-Eintrag

ord-88d68bf268d64e84b574b8237297569f

Quelldatensatz

uspto-grants-2012_07

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08222219B2