Acetic Acid → 5-(3-Bromopropylidene)-5,11-dihydro[1]benzoxepino[2,3-b]pyridine

Participants

Reaction Conditions

Reaction Steps

To a 2 L eggplant flask with a magnetic stirring bar was added 75.0 g. of 5-Cyclopropyl-5,11-dihydro[1]benzoxepino[2,3-b]pyridin-5-ol (0.30 mole) and 75 mL of acetic acid. The solution was cooled with water (ca. 10° C.), 120 ml of 47% aqueous hydrobromic acid was added over a period of 5 minutes. The reaction mixture was warmed to 60° C., stirred for an hour, and evaporated (aspirator vacuum, ca. 50° C.) to ca. 200 mL. The reaction mixture was poured to 1500 mL of saturated aqueous sodium bicarbonate, the mixture is extracted with two 800 mL portions of ethyl acetate, and the combined organic extracts are washed with 500 mL of saturated aqueous sodium chloride. The organic solution was dried with anhydrous magnesium sulfate, filtered, and evaporated (aspirator vacuum, ca. 30° C.). The oily residue was chromatographed on 500 g. of Silica gel 60 by eluting with 5:1-4:1 (v/v) hexane-ethyl acetate mixture. The elution was evaporated, giving the titled compound as a pale yellow oil.

Provenance & Evidence