Hydrochloric Acid → (5R)-3-[6-(But-3-ynyloxy)hexyl]5-(2,2-dimethyl-4H-1,3-benzodioxin-6-yl)-1,3-oxazolidin-2-one

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Reaction Steps

(5R)-5-(2,2-dimethyl-4H-1,3-benzodioxin-6-yl)-1,3-oxazolidin-2-one (10 g) in DMF (100 ml) was added dropwise to a stirred suspension of sodium hydride (60% oil dispersion, 2.33 g) in DMF (50 ml) with stirring under nitrogen and maintaining the internal temperature at 0°. Stirring was continued at 0-5° for 1 h. The mixture was recooled to 0° and a solution of 6-bromohexyl but-3-ynyl ether (14.7 g) in DMF (50 ml) was added over 1 min. The mixture was then stirred at 20-30° for 2 h. 2M HCl (9 ml) was added and the mixture was partitioned between water and diethyl ether. The aqueous layer was extracted with more diethyl ether and the combined organic layers were washed twice with brine. After drying (MgSO4) the solution was concentrated and loaded onto a column of silica gel (600 g) set up in diethyl ether:petroleum ether (bp 40-60°) (1:2). The column was eluted successively with this mixture, then (1:1) and then diethyl ether to give the title compound (13.88 g) LCMS RT=3.45 min.

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