In a 10 mL of 0.1M potassium phosphate buffer (pH 7.5) were dissolved 10 mM DTT, 0.5M pyruvate, 100 mg of 6-O-acetylmannosamine, prepared as described above, and 1.5 mg NeuAc aldolase (36 U). The reaction mixture was incubated at 37° C. for 8 days followed by lyophilization. The lyophilized powder was dissolved in a small amount of water and directly applied to a Bio Gel P-2 column (3×90 cm) and eluted with a flow rate of 6 mL/40 minutes at 4° C. To remove the trace amount of contaminated NeuAc due to the hydrolysis of the product, another gel filtration was required. Compound 201 was obtained in 47 percent yield. Its physical data were consistent with the reported data.
