54 



NATURE, FORMATION, AND ACTIVITIES 



candidin, amphotericin B, caiidicidiii, tri- 

 chomycin, and perimycin. 



Pimaricin has the empirical formula 

 C34H49NO14 and the following sti-ucture: 



heptaenes. Of the five hexaenes reported in 

 the literature, four are said to ha\'e some 

 kind of antil)acterial activity. 



The chemistry of the heptaenes has been 



H2X 



-OH 



The nitrogen is present in the form of an studied chiefly by Borowski and coworkers 



amino group in a five-carbon sugar moiety, (1960). Amphotericin B and candidin are 



mycosamine. A large lactone ring of the xevy closely related substances, each of 



type found in the bacterial macrolides, such which contains one atom of nitrogen located 



as erythromycin, is formed in part by the in the amino sugar, mycosamine. In contrast, 



tetraenic chromophore. A carl)oxyl and an candicidin, trichomycin, and perimycin have 



epoxide group are attached to the large twoaminogroupsper molecule. In candicidin 



lactone ring. Alycosamine is also present in and trichomycin, one of these amino groups 



the molecule of another tetraene, nystatin, is located in a mycosamine moiety and the 



and in the molecule of some of the hep- other in a p-aminoacetophenone moiety: 



taenes. Nystatin has a larger molecule than 

 pimaricin; it has the empirical formula 



Lagosin and filipin are two pentaenes 

 which do not contain nitrogen: 



CH3(CH2)4CHOH 



CHa— CO— r ^— NH2 



Perimycin dilTers in that one of the amino 

 groups is located in an amino sugar moiety 



OH 

 Lagosin: R = OH 



The large lactone ring of each is formed of 

 27 carbons and includes the pentaenic 

 chromophore. 



Other pentaenes, such as antibiotic PA 

 1").'^, contain nitrogen. 



The hexaenes are the least known poly- 

 enes. They have not been isolated as often 

 as the tetraenes, the pentaenes, and the 



OH 



Filii)iii : 



of unknown structure and the other is in a 

 p-aminophenylacetone moiety : 



CH,— CO— CH,,- 



-NH2 



Perimycin, unlike other heptaenes, does not 

 have a carboxyl group. 



With the help of the keys, sunnnaries of 



