A well-stirred suspension consisting of 3.59 g (0.00915 mole) of 3-(3-ethoxycarbonylpropionyl)-8-methoxy-4-(2-methylphenylamino)-quinoline (the product of Example 1) in 200 mL of methanol was cooled to 5° C. and 173 mg. (0.0045 mole) of sodium borohydride (available from the Aldrich Chemical Company, Inc. of Milwaukee, Wis.) was immediately thereafter slowly added in small-divided portions, followed by continued stirring of the reaction mixture at 5° C. for a period of 45 minutes. At this point, a fresh batch of 90 mg of sodium borohydride was added to the stirred reaction mixture and further stirring was then continued at 5° C. for a period of one hour. Upon completion of this step, the pH of the resulting homogeneous solution was next adjusted to a value of pH 7 by the careful addition of glacial acetic acid, followed by filtration and subsequent evaporation of the resulting filtrate under reduced pressure to eventually give a crystalline product as the residue. Recrystallization of the latter material from methanol-water then gave a nearly quantitative yield of pure 3-(3-ethoxycarbonyl-1-hydroxypropyl)-8-methoxy-4-(2-methyl-phenylamino)quinoline as a partial hemihydrate, m.p. 133°-135° C. The pure product was further characterized by means of mass spectrum (MS) analysis and nuclear magnetic resonance (NMR) data, in addition to elemental analysis.
