Chemical Constituents of the Animal Body. 209 



CHO 



CHO 



These can be synthesized from pentoses, or they can be 

 degraded into pentoses by reaction IV. (Ruff's reaction). 

 (1) Will be degraded to the pentose 



CHoOH 



CHO 



H 

 H 



OH 



OH 



H 



-OH which may be written OH 



H 



OH 



CHO 



OH 

 H ' 



H 



CH 2 OH 



which will yield an optically active dibasic acid on 

 oxidation. 



(2) Will be degraded to the pentose 



CH 2 OH 



CHO 



OH 

 H- 



H 



H 



-OH which may be written OH- 



H 

 CHO 



H 



-OH 

 H 



OH 



CH 2 OH 



which will yield an optically inactive dibasic acid on 

 oxidation. 



Now the constitution of the various pentoses can, as 



(1,997) H 



