To a stirred solution of 1.0 gram (0.0045 mole) of 4-(2-(diethylamino)ethoxy)benzaldehyde and 0.65 gram (0.0045 mole) of 6-aminoquinoline (available from Aldrich Chemical Company) in 25 mL of 1,2-dichloroethane (DCE, available from Aldrich Chemical Company) was added 0.3 mL (0.0045 mole) of glacial acetic acid (available from J. T. Baker Inc.) followed by 1.4 grams (0.0068 mole) of sodium triacetoxyborohydride (available from Aldrich Chemical Company). Upon completion of addition, the reaction mixture was stirred at ambient temperature for three hours. At the conclusion of this period, 50 mL of 10% aqueous sodium hydroxide was added dropwise. The resulting solution was extracted with three 25 mL portions of diethyl ether. The extracts were combined, washed with one 25 mL portion of an aqueous solution saturated with sodium chloride, dried with sodium sulfate and filtered. The filtrate was concentrated under reduced pressure, yielding 1.25 grams of a dark brown paste. The dark brown paste was purified by column chromatography on silica gel, yielding 0.13 gram of Compound 15. The NMR spectrum was consistent with the proposed structure.
