L-デヒドロアスコルビン酸

用途生理作用研究用。

解説デヒドロアスコルビン酸，C6H6O6(174.11)．L-アスコルビン酸を酸化すると生成する．酸化型で，酸化型ビタミンCともよばれる．白色の結晶．分解点225 ℃．無水物は二量体で存在する．グルタチオンなどの還元剤でアスコルビン酸に変換され，生体内ではアスコルビン酸とともに酸化還元に関与し，抗壊血病因子として作用する．

使用The reversibly oxidized form of ascorbic acid.

純化方法Crystallise dehydro-L(+)-ascorbic acid from MeOH. The anhydrous acid is formed by heating it in a vacuum at 100o/1hour to give a crisp glassy product which when shaken with absolute EtOH and then kept at 0o for 2days gives microcrystals of the anhydrous acid. This is then washed with absolute EtOH and dried in a vacuum. It has m 225o(dec) and is stable in acidic solution but decomposes rapidly in alkaline solution. A 1% solution of the anhydrous acid when dissolved in phthalate/HCl buffer pH 3.5 at 60o and cooled to 20o has [] 20D +56o(0minutes), +53.5o(2hours), +19o(3days), -2o(5days) and -6o(6days); then it becomes orange in colour. A freshly prepared 1% solution in H2O has [] D +50o(0minutes), +44o(2hours), +16o(3days) and 0o(5days). [Herbert et al. J Chem Soc 1270 1933, Kenyon et al. J Chem Soc 158 1948, Beilstein 18/5 V 411.]