Some Metabolic Products of Basidiomycetes 9 



Diatretyne amide differs from agrocybin only in that the former 

 possesses a double bond in place of one of the triple bonds of agrocybin 

 and a carboxyl group instead of the terminal hydroxyl group. It differs 

 from diatretyne nitrile in that it possesses an amide group in place of 

 the nitrile group. The rest of the molecule is, apparently, identical, 

 but the possibility that XIV and XV differ also in their configuration 

 (cis-trans) at the double bond has not been excluded. The effect of 

 this difference, or these differences, on the antibiotic activity is rather 

 striking. Diatretyne nitrile is active against Staphylococcus aureus 

 at a concentration of about 0.1 jxg. per ml., whereas diatretyne amide 

 is inactive at a concentration 8000 times as great. 



The antibiotic compounds isolated from basidiomycetes suggest prob- 

 lems which are of interest both in their chemical and biological aspects. 



If any one tendency, from a chemical standpoint, appears to be 

 common to this group of compounds, it is that they seem to possess, 

 in general, an enhanced reactivity compared with other compounds 

 of related structure. Thus, the illudins, which are notably similar to 

 the santonins in their behavior, undergo the characteristic change with 

 acid, described above, under considerably milder conditions. A large 

 proportion of the basidiomycete polyacetylenes, in contrast to the 

 synthetic ones and to those isolated from higher plants, are too unstable 

 to be obtained in crystalline form but can be handled only in solution. 

 Further, the allene to acetylene conversion of nemotin to nemotin A 

 takes place under milder conditions than those reported for other simi- 

 lar rearrangements. 25 - 36 The behavior of other antibiotic compounds 

 isolated, on the other hand, does not support the idea of enhanced 

 reactivity. Pleuromutilin, ochracic acid, and diatretyne nitrile are 

 relatively stable chemically, although all three of these compounds 

 have a high degree of antibiotic activity. 



The basidiomycete compounds present other interesting chemical 

 problems and shed further light on little-explored questions. The 

 illudins, fomecins, and pleuromutilin exhibit what appears to be some- 

 what unorthodox or at least unusual chemical behavior. The structures 

 of the biformynes and of the precursors of biformyne 2 and agrocybin 

 need clarification. The availability of compounds such as the nemotins 

 and the drosophilins (along with mycomycin) provides models (not 

 readily available synthetically) for study of the allene to acetylene 

 shift as influenced by other structural features of the molecule. The 

 behavior of agrocybin on catalytic reduction, using platinic oxide 

 catalyst (loss of hydroxyl oxygen), serves as a reminder, particularly 

 important in working with those polyacetylenes which are too unstable 



