The syrup obtained in Example 1 was centrifuged with benzene and concentrated under reduced pressure, and dissolved in a mixed solvent of methylene chloride/N-methyl-2-pyrrolidone (4/1) (0.3 ml), and WSC (1.44 mg, 7.5 μmol) and 1-hydroxybenzotriazole (1.01 mg, 7.5 μmol) were added. This solution was added to 10 μl of TOYO-Pearl resin (TSKgel AF-amino; 0.01 mmol amine is present in 100 μl) and shaken at room temperature overnight. After completion of the reaction, the resin was thoroughly washed with a mixed solvent of methylene chloride/N-methyl-2-pyrrolidone (4/1), and DMF, and the percent condensation yield was determined by the ninhydrin test (about 29%). A mixed solution of acetic anhydride/DMF (1/4) (0.3 ml) was added to the resin obtained, and this was followed by shaking at room temperature for 30 minutes. After completion of the reaction, the resin was thoroughly washed with methylene chloride, dimethylformamide (DMF) and 20% aqueous ethanol, and this resin was used as the affinity resin in the subsequent experiments.
