D-Galactonic acid

Use

Crystallise D-galactonic acid from EtOH or aqueous EtOH. It cyclises to D-galactono-1,4-lactone, m 134-136o, and mutarotates in 1hour to [] 546 -92o (c 5, H2O). It can also be obtained from the Na salt by adding 10times its weight of acetic acid, warming till just brown, cooling, filtering off the crystals and drying them. It has m 145-146o, [ ] D –13.6o (c 1, H2O, 2minutes and mutarotates to – 5 7 . 6o). [Blackburn & Upson J Am Chem Soc 55 2514 1933, Beilstein 3 IV 1257, and for the -lactone see below.]