POLYCARBOXYLIC ACIDS 



311 



feeding of suberic acid,^-* sebacic acid,*'-'^ or the Cie or Cis dicarboxylic acids.^^ 

 However, the corresponding cychc compound, cyclohexanol, probably 

 cannot be converted to adipic acid. Although WeitzeF showed that cyclo- 

 hexanol or l,3-dimethyl-5-cyclohexcne was easily oxidized in vitro by 

 appropriate means to adipic acid, or to Q:,/3-dimethyladipic acid, respec- 

 tively, he was unable to demonstrate any evidence of this transformation 

 in the dog when either of these compounds was fed in doses of one g./kg. 

 daily. On the other hand, Benihard*^^ was unable to detect either phenol, 

 which would result from dehydrogenation, or adipic acid, which would 

 result from an oxidative splitting, after cyclohexanol had been injected 

 into dogs in doses of 0.238 g./kg./day. However, he was of the opinion 

 that adipic acid would arise following increased doses of cyclohexanol. 

 Weitzel^^ also obtained negative results, insofar as adipic acid formation 

 is concerned, with another cyclic compound, camphoric acid. After 

 feeding 76 g. of the pure compound to a dog over a six- day period, this 

 investigator was able to recover 08. 4 g. of pure acid from the urine. The 

 comparative structure of these compounds is shown below- 



CH2— 

 CH, 



CH2 



CH2 



CH2 



HO— CH ^ 



Cyclohexanol 



CH- 

 CH 



COOH 



CH2 

 HCCH3 

 CH2 

 CHsC 



CH, 



H2 CH: 



:i- 



-CHi 



H 



CH3 



i- 



1,3-Dimethyl- 

 5-cyclohexene 



COOH 



Camphoric acid*' 



When alkyl side chains are introduced on the adipic acid molecule, con- 

 siderable changes in the metabolism of the resulting compound occur. 

 a,/3'-Dimethyladipic acid (HOOC • CHCCHs) • CH. • CHCCHs) • CHo • COOH), 

 was less well utilized by dogs than was a-methyladipic acid (HOOC : CH- 

 (CH3) • CH2 • CH2 • CH2 • COOH) .87 When the substituent alkyl group was 

 introduced into the /3-position, WeitzeF observed the following "toler- 

 ances" (g./kg./day) for the several adipic acid derivatives: n-adipic acid, 

 6.27; /3-methyladipic acid, 0.16; /?-ethyladipic acid, 0.13; jS-n-propyl- 

 adipic acid, 0.11; /3-n-butyladipic acid, 0.15; iS-?i-hexyladipic acid, 0.40; 



8< K. Bernhard and M. Andreae, Z. physiol. Chem., 245, 103-106 (1937). 



85 B. Flaschentrager and K. Bernhard, Z. physiol Chem., 238, 221-232 (1936). 



8« R. Emmrich and I. Emmrich-Glaser, Z. physiol. Chem., 266, 183-192 (1940). 



8' G. Weitzel, Z. physiol. Chem., 285, 58-77 (1950). 



88 K. Bernhard, Z. physiol. Chem., 248, 256-276 (1937). 



