POLYCARBOXYLIC ACIDS 309 



study of higher homologues of siu^cinic acid, Thomas, Weitzel, and Neu- 

 mann^^ reported that these compounds are readily utilizable by the dog 

 when given in dosages of 0.1 to 0.2 g. per kg. body weight per day. The 

 following amounts of succinic acid were isolated from the urine after 

 dosages of 12 or 18 g. of the alkyl succinates: 12 g. heptylsuccinate, 9.7 

 mg. succinate; 18 g. octylsuccinate, 63.6 mg.; 12 g. nonylsuccinate, 4.3 

 mg. ; 18 g. decylsuccinate, 133.8 mg. ; 18 g. undecylsuccinate, 158.0 mg. ; 

 18 g. dodecylsuccinate, 112.4 mg. ; and 12 g. cetylsuccinate, 45.4 mg. 

 Lincke^^ also reported increased succinate after similar alkylated suc- 

 cinates had been given. Moreover, these synthetic compounds were 

 found to be largely utihzed, aiid no traces of them were excreted in the 

 urine. The latter investigation indicated that some increase in oxalic 

 acid elimination occurred after the alkylated succinates had been fed. 



Emmrich«s found that methyl succinic acid (H00C-CH(CH3) -CHa-- 

 COOH) is difficultly utihzed by the dog; after the administration of 20 g. 

 of this compound, as much as 43.8% was excreted in the urine. It was 

 also noted that a small amomit (2.2%) was excreted as methyl fumarate 

 (HOOC • C (CHs) : CH • COOH) . In an extension of these studies, WeitzeP^ 

 reported that sj^mmetric dimethylsuccinate (HOOC-CHCHs-CHCHs-- 

 COOH) is excreted to the extent of about 60% by the dog; it is thus 

 utilized with more difficulty than is the monomethyl derivative of suc- 

 cinic acid. Moreover, no difference in tolerance could be demonstrated 

 between the meso- and the racemic forms of the symmetrical compound. 

 Since an increased excretion of normal succinate followed the administra- 

 tion of dimethylsuccinic acid, WeitzeP^ postulates that the latter com- 

 pound disturbs the normal succinate metabolism in the tissues. Bodur''° 

 observed that the unsymmetrical dimethylsuccinate is even less efficiently 

 utilized by the dog than is the symmetrical isomer, since as much as 85% 

 of the ingested unsymmetrical product w^as isolated in the crude form. 

 However, there was no evidence that the unsymmetrical dimethylsuccinate 

 was converted to trimethylacetic acid ((CH3)3C-COOH), as had been 

 assumed. 



Succinate itself is rapidly oxidized. Flaschentrager and Hosoda'^* 



«« K. Thomas, G. Weitzel, and P. Neumann, Z. physiol. Chem., 282, 192-200 (1947). 



^' H. Lincke, Das Stoffivechselverhalten alkylierter Bernsteinsauren beim Hunde, Dis- 

 sertation, Zurich, 1945; cited by K. Thomas, G. Weitzel, and P. Neumann, Z. physiol. 

 Chem., 282, 192-200 (1947) on basis of personal communication from K. Bernhard. 



88 R. Emmrich, Z. physiol. Chem., 261, 61-70 (1939). 



" G. Weitzel, Z. physiol. Chem., 282, 200-205 (1947). 



™ H. Bodur, Z. physiol. Chem., 282, 206-207 (1947). 



'1 B. Flaschentrager and T. Hosoda, Z. physiol Chem., 282, 215-220 (1947). 



