PANTOTHENIC ACID 633 



tauramido-4-methoxybenzene, pantoyltauramido-4-methylbenzene and 

 pantoyltauramido-4-nitrobenzene caused similar alterations in the blood 

 picture of chicks. The toxicities were roughly proportional to the anti- 

 malarial activities. 



N-Pantoyl Amino Acids. Investigations concerning the specificity of 

 pantothenic acid have resulted in the preparation of a number of 

 N-pantoyl derivatives of amino acids or their esters. DL-Pantolactone 

 was condensed with the esters of DL-alanine, DL-/?-aminobutyric acid, 

 L-aspartic acid and DL-lysine, and the resulting products were found to 

 be inactive in replacing pantothenic acid as a growth factor. 71 In the 

 isolation of pantothenic acid from livers of tunny fish, an impurity which 

 was present in higher concentrations than pantothenic acid was found 

 to be a homologue of pantothenic acid, composed of L-leucine and a 

 pantoic acid homologue containing seven carbon atoms. This suggested 

 the preparation of the pantoyl derivative of L-leucine, which was found 

 to be inactive in replacing pantothenic acid for Streptobacterium plan- 

 tarum. 12 Pantoyl-y-aminobutyric acid has been found to be unable to 

 replace pantothenic acid in preventing achromotrichia in rats. 16 Also, the 

 pantoyl derivatives of lysine, leucine, and valine have no marked activity 

 in replacing the requirement of Proteus morganii for pantothenic acid. 15 



Condensation products of DL-pantolactone with glycine, DL-a-amino- 

 butyric acid, DL-a-aminoisobutyric acid, DL-a-amino-a-ethylbutyric 

 acid, and DL-norvaline are essentially inactive for Lactobacillus ara- 

 binosus 17-5. 73 Corresponding condensation products of phenylalanine, 

 2-aminocyclohexanecarboxylic acid, and nipecotic acid are also essentially 

 inactive for Lactobacillus casei. 62 



Prepared as a possible substitute for pantothenic acid, the cc-methyl 

 analogue of pantothenic acid was found to have slight growth-promoting 

 activity, particularly for Saccharomyces cerevisiae G. M.; however, the 

 compound was found to prevent the utilization of pantothenic acid by 

 Lactobacillus casei. 74 ' Several N-pantoyl amino acids, as indicated in 

 Table 28, have since been found to be competitive antagonists of panto- 

 thenic acid. With the possible exception of N-pantoyl-e-aminocaproic 

 acid, N-pantoyl-/?-aminobutyric acid appears to be the most effective of 

 this group as an antagonist of pantothenic acid. Since the product tested 

 is a mixture of two racemic diastereoisomers, the inhibitory activity may 

 result from the action of only one of the four forms, and certainly results 

 from the action of no more than the two forms containing the pantoyl 

 group of D-configuration. For comparison with the other analogues, the 

 inhibition indices for N-pantoyl-/?-aminoisobutyric acid presumably 

 should be doubled, since it alone was prepared from D-pantolactone. 



In some cases with the a-substituted pantothenic acids, N-pantoyl- 



