log Polyenes and Polyynes, Excluding Polyene Macrolides 

 HC=C— C^C— CH=C=CH— CH— CH2— CH2— COOH 



a culture grown on ethanol with l-C^*-labeled acetic acid added 

 to the medium, labeling was found in the xylose as well as in 

 the acetylenic acid. It was assumed that in the latter case, 

 where the molecule was synthesized entirely from C2 units, the 

 xylose was produced by way of intermediates closely related to 

 glucose. Glucose itself acted as the xylose precursor, then, in 

 the first experiment. A closer analysis of the labeling pattern 

 of the xylose moiety led to the suggestion that the pentose was 

 formed from glucose by way of glucuronic acid followed by 

 decarboxylation. 



Many of the acetylenic acids have antibiotic properties. 

 A review of polyacetylenes was published recently.* 

 About a dozen more compounds of this type are listed in the 

 addendum. 



190 Agrocybin, C8H5O0N, unstable compound white crystals, darken- 



ing in air, m.p. 130-140° (dec. explosively), U.V. 216, 

 224, 269, 286, 304, 325 m^u in 95% ethanol. 



HOCH.— C=C— C^C— C=C— CONH2 



Agrocyhe dura 



Marjorie Anchel, J. Am. Chem. Soc. 74 1588 (1952). 



J. D. Bu'Lock, E. R. H. Jones, G. H. Mansfield, J. W. Thomp- 

 son and M. C. Whiting, Chem. and Ind., 990 (1954). (Struc- 

 ture) 



P. J. Ashworth, E. R. H. Jones, G. H. Mansfield, K. Schlogl, 

 J. M. Thompson, M. C. Whiting, /. Chem. Soc, 950 (1958). 

 (Synthesis) 



191 Diatretyne 1, CsHjOgN, unstable crystals, m.p. 198° (dec. ex- 



plosively), U.V. 223, 260, 275, 290, 309 m^ m 95% etha- 

 nol. 



HOOC— CH=CH— C^C— C=C— CONH2 

 and 



4E. R. H. Jones, Proc. Chem. Soc, 199-211 (1960). 



