CLASSIFICATIOX AND STRUCTURE OF FATTY ACIDS 39 



b. Hydnocarpic Acid. Hydnocarpic acid is usually associated with 

 chaulmoogric acid. The structure of this acid was first suggested by the 

 investigations of Power et a/.,^^^'^"^ but was only completely understood 

 after the experimental work of Shriner and Adams. ^^^ It was shown to be 

 ll-[2-cyclopenten3d]undecanoic acid, which has the structure shown in the 

 accompanying formula. 



CHaCHzCHCCHaJioCOOH 



CH=^CH 



Hjdnocarpic acid 



Hydnocarpic acid thus is related to palmitic acid, while chaulmoogric acid 

 has the same numl)er of carbons as stearic acid. The properties of hydno- 

 carpic acid are analogous to those of chaulmoogric acid. 



c. Gorlic Acid. Dean, Wrenshall, and Fujimoto^^^'^^- originally sug- 

 gested that chaulmoogra and similar oils contained a liquid cyclic acid 

 more unsaturated than chaulmoogric acid. On hydrogenation of the oil, 

 it was found that a dihydrochaulmoogric acid was formed in which the 5- 

 carbon ring was saturated but in which the side chain had an unsaturated 

 bond. This acid was first separated from the oil of the seed of Oncoha 

 echinata (commonly called gorli seed) by Andre and Jouatte,^''^ who named 

 it gorlic acid. The same acid was later obtained by Paget'^^ and by Cole 

 and Cardoso^'^^ from the oil of the sapucainha tree {Carpoti'oche brasiliensis) . 

 Paget called it dehydrochaulmoogric acid. Since it yielded adipic acid 

 and 4-carbox3amdecanedioic acid upon oxidation, its structure was es- 

 tablished as 13-(2-cyclopentenyl)-6-tridecenoic acid. In the gorli seed, 

 gorlic acid makes up 14.7% of the total fatty acids. ^^^ 



CHa CH2CH(CH2)6CH=CH{CH2 )4 COOH 



I I 



CH==CH 



Gorlic acid 



d. Other Cyclic Acids. A number of homologues of chaulmoogric acid 

 hsLxe been isolated from the oil of Hydnocarpus unghtiana and H. 

 (inthelmintica by Cole and Cardoso. '^^•^''^ These are called alepric, alepry- 

 iic, aliprestic, and aleprolic acids. They differ from chaulmoogric acid in 

 the length of the side chain. 



e. Structure as Related to Antileprosy Action. The development of the 

 in vitro test for activity based upon the bactericidal action on Bacillus 



1" E. Andre and D. Jouatte, Bull. soc. chim. [4], 43, 347-360 (1928). 



"* H. Paget, /. Chem. Soc, 1937, 955-960. 



1" H. I. Cole and H. T. Cardoso, ./. Am. Chem. Soc, 60, 612-614; 614-017; 617-619 

 (1938). 



i"« H. I. Cole and H. T. Cardoso, /. Am. Chem. Soc, 61, 2349-2351; 2351-2353; 3442- 

 3445 (1939). 



