Hexane → 2-Ethoxybenzothiazole

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

Exactly 5.8 g of hexane-wet sodium spheres (0.02 mole) was carefully dissolved in 100 ml of anhydrous ethanol. To the resulting cooled sodium ethoxide solution, stirring at 25° C. under nitrogen, was added a solution of 33.8 g (0.2 mole) of 2-chlorobenzothiazole in 100 ml of ethanol over a seven minute interval. There was a strong exotherm during this addition. The reaction mixture was heated to a reflux over 15 min and held at reflux for one hour. The apparatus was then fitted for downward distillation and the ethanol distilled from the reaction mixture at atmospheric pressure over a period of one hour. The cooled oily residue was dissolved in 50 ml of methylene chloride and rapidly stirred for 10 min with 400 ml of water. The organic layer was separated, dried over anhydrous potassium carbonate and stripped of solvent under vacuum. The crude product was distilled under reduced pressure to give 33.15 g (93%) of analytically pure 2-ethoxybenzothiazole, b.p. 78°-80° C., 0.11mm. (lit b.p. 80°-81°, 0.2 mm.) : UV (MeOH):λmax 218 nm (ε=31,100),λmax 245 nm (ε=7,800),λmax 277 nm (ε=1,100),λmax 287 nm (ε=1,060).

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