190 



Procedure 6'^ 



ASCORBIC ACID 



CHO 



I 

 H— C— OH 



I 

 HO— C— H 



I 

 H— C— OH 



H— C— OH 

 I 

 CH2OH 



XXIV 

 D-Glucose 



HNOj 



COOH 

 I 

 H— C— OH 

 I 

 HO— C— H 



? 



H— C— OH 



H— C— OH 



COOH 



XXV 



Glucosaccharic 

 acid 



CO — 

 I 

 H— C— OH 



H.o^ HO-C-H 



Na 



H— CO- 



I 

 H— C— OH 



COOH 



XXVI 



Glucosaccharo- 

 1 ,4-gamma-lactone 



COOH 

 I 

 HO— C— H 

 I 

 „ HO— C— H 

 i^ I 



H— C— OH 



HO-C-H 



I 

 CH2OH 



XXVII 



L-Gulonic acid 



- H»o 



CHO 



I 

 HO— C— H 



I 

 H— C— OH 



I 

 HO-C— H 



I 



CH2OH 



XXX 



L-Xylose 



Fe 



COOCa/2 



HO— C— H 



I 

 HO— C— H 



I 

 H— C— OH 



HO— C— H 

 I 

 CH2OH 



XXIX 



CO— 



HO— C— H 



I 

 HO— C— H 



H— CO — ' 

 I 

 HO— C— H 

 I 

 CH2OH 



XXVIII 



L-Gulono- 



gamma-lactone 



XXIII 



L-Lyxosazone 

 or L-xylosazone 



IceHjCHO 



XII 



L-Lyxosone 

 or L-xylosone 



The synthetic L-ascorbic acid obtained in this manner was chemically 

 identical in every way with the naturally occurring vitamin C, and it was 

 equally potent in curing scurvy in guinea pigs.'^- -" This work marked an 

 important step in organic chemistry, for L-ascorbic acid was the first vitamin 

 to be synthesized. 



The success of the osone method for sj'^nthesizing L-ascorbic acid and 

 various analogs of ascorbic acid depends to no small extent on the purity 

 of the sugar osazone. If the latter is a pentosazonc, as was the case in the 



