Calcium Acetate → L-Tagatose

To a 25 ml Erlenmeyer flask, equipped with a magnetic stirrer, was added 0.5 g L-galactose, 5 ml water, 0.2 g calcium hydroxide, and 22 mg calcium acetate. The mixture was stirred. After 2 hours, the solution was filtered to collect the calcium hydroxide-L-tagatose complex that had formed. The sticky complex was resuspended in 5 mL of H2O, and CO2 was bubbled through the slurry until the pH was below 7. The solution, after filtering off the calcium carbonate, was deionized as in Example 1 and concentrated in vacuo to a syrup which, after seeding with a few L-tagatose crystals, provided 0.22 g of pure L - tagatose, a 44 % yield.