Ammonium Chloride → 2-Acetylamino-5-benzyl-7-hydroxy-benzo[b]thiophene-3-carboxylic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

A suspension of the bromide 02-5 (8.5 g, 18.9 mmol), LiBr (1.8 g, 20.8 mmol, 1.1 equiv.), Li2CO3 (1.5 g, 20.8 mmol, 1.1 equiv.) and DMF (200 mL) was heated to 150° C. for 4 h under a N2-atmosphere. The reaction mixture was cooled to RT and poured into saturated aqueous NH4Cl (750 mL). The aqueous layer was extracted with EtOAc (3×200 mL). The combined organic layers were washed with H2O (3×200 mL), sat. aq. NH4Cl (200 mL) and dried over Na2SO4. The solvent was removed in vacuo to give the crude product. The solid was washed with Et2O (25 mL) to give 02-6 (1.52 g, 4.1 mmol, 22%). The filtrate was evaporated and the residue was purified by column chromatography (SiO2, EtOAc/hept=1/1) to give another fraction of 02-6 (2.5 g, 6.8 mmol, 36%) as a yellow solid (total yield: 4.3 g, 11.7 mmol, 62%).

Provenance & Evidence