CHAPTER 3 



DEHYDROACETATE 



Since this substance inhibits succinate dehydrogenase and may exert some 

 of its effects because of a structure analogous to certain cellular metabolites, 

 it is appropriate to discuss it at this time, although little of its basic meta- 

 bolic effects is understood. In a study of the formation of ethyl acetoacetate, 

 Geuther (1866) found that distillation of this substance yielded a crystalline 

 material, to which he gave the name dehydroacetic acid. It was soon shown 

 to contain a pyran ring structure (Feist, 1890) and has been used extensively 

 in organic preparative procedures. The effects on biological systems were not 

 studied until Brodersen and Kjaer (1946) in Copenhagen investigated a se- 

 ries of unsaturated lactones for antibacterial activity. They reasoned that 

 several such compounds are antimicrobial — anemonin from species of Ra- 

 nunculaceae, parasorbic acid from the mountain ash (Sorbus), Dicumarol 

 from sweet clover, penicillic acid from certain species of Penicillium, kojic 

 acid from Aspergillus, patulin (clavacin) from various fungi, and others — 

 and that a correlation between activity and the — — CO — C=C — struc- 

 ture might exist: 



Q 



^O o 



OH 



H,C 



.CH3 

 ^CH, 



OCH, 



Anemonin 



Parasorbic acid 



Penicillic acid 



O^ .OH 



O^ ^CH,OH 



Patulin 



Kojic acid 



617 



