200 



ASCORBIC ACID 



thetic 2-amino"' and 2,3-diamino^''^ derivatives of L-ascorbic acid are like- 

 wise inactive. Reference may also be made to reductinic acid, produced 

 from glucuronic acid, pectin, and furfural, '°^ and to reductone which is 



-CO 



C— OH 



11 



C— OH 



I 

 ^OC— H 



H— C— OH 



I 

 CH2OH 



D-Xj'loascorbic 



acid (o-ascorbic 



acid)'^' ''■ '''■ "« 



m.p. 192° [all, - 23° 



TABLE II 

 Antiscorbutically Inactive Substances 



-CO 



—CO 

 C— OH 



C— OH 



I 

 OC— H 



I 

 HO— C— H 



I 

 CH2OH 



C— OH 



II 



C— OH 



I 

 -OC— H 



H— C— OH 



I 

 H— C— OH 



-CO 



I 

 C— OH 



II 



C— OH 



I 

 •-OC- H 



I 

 HO— C— H 



I 

 H— C— OH 



I 

 CHoOH 



CH2OH 



L-Araboascorbic D-Glucoascorbic D-Galactoascorbic 



acid''®' ^^' ^"'^ acid"*®- ^- ^"^^ '"^ acid''®' ^' ^'^^' '"^ 



i.p. 174°, [alo - 17° m.p. 140° (mono- m.p. 134°, [a]^ - 6° 



hydrate), [a]^ - 22° 



I CO 



I 

 C— OH 



II 



C— OH 



-OC— H 



H— C— OH 



HO— C— H 



CH2OH 



L-Guloscorbic 



acid «• «'■ ''' 



m.p. 184°, 



[aL - 22° 



-CO 



C— OH 



II 



C— OH 



-OC— H 



HO— C— H 



HO— C— H 



CHoOH 

 L-AUoascorbic 

 acid S9 

 m.p. 177°, 

 Wd + 29° 



—CO 



C— OH 



II 



C— OH 



-OC— H 



CH2OH 



L-Erythro- 

 ascorbic acid^" 

 m.p. 161°, 

 ["Id + 9° 



-CO 



C— OH 



II 



C— OH 



I 

 ^0CH2 



Hydroxy tetronic 

 acid 100. i«5 



m.p. 153°, optically 

 inactive 



formed from sugars such as glucose by treatment with alkalies' °*"'" (see 

 Table III). Both show the same vigorous reducing properties and similar 

 light absorption characteristics as L-ascorbic acid, Init l:)Oth are inactive. 

 Dihydroxymaleic acid and hydroxytetronic acid, referred to above (Table 

 III), are also inactive. 



