Acetic Anhydride → 3-Dimethylaminopropyl 4-[3-(3-acetoxy-4-acetyl-2-propylphenoxy)propoxy]-3-bromobenzoate

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Reaction Steps

In a mixture of pyridine (5 ml) and acetic anhydride (5 ml) was dissolved 3-(N,N-dimethylamino)propyl 4-[3-(4-acetyl-3-hydroxy-2-propylphenoxy)propoxy]-3-bromobenzoate (1 g). The solution was stirred at 110° to 120° C. for about 18 hours, followed by concentration. The residue was chromatographed on a column of silica gel. The elution was conducted with ethyl acetate, and the eluate was evaporated. The resulting oily substance was dissolved in ether, to which was added an ether solution of anhydrous oxalic acid. The resultant crystals were collected by filtration, which were washed with ethanol and then with isopropyl ether, followed by drying to give 866 mg of 3-(N,N-dimethyl-amino)propyl 4-[3-(4-acetyl-3-acetoxy-2-propylphenoxy)propoxy]-3-bromobenzoate.mono-oxalate, m.p. 141°-142° C.

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