206 



CHEMICAL NATURE OF ANTIBIOTIC SUBSTANCES 



3. The phenyl ring, or preferably 2 and 3 combined as phenylacetu- 

 rates, a-phenylacetamide or 3-phenylethylamine. 



Several forms of penicillin or "natural penicillins" have been iso- 

 lated (715). They were all found to have the empirical formula 

 C9H11O4SN2.R. These forms may be presented as follows: 



O H 



CH3 

 I 

 S C CH3 



P = CH3 CH2 CH--CH CH2 C — N— CH — CH 

 * I \ 



0=C N CHCO2H 



CH3 



I 

 OH S CCH3 



Q = ^_^CH2C-N-CH-CH 



0=C N CHCO2H 



X = HO^ 



-/ 



CH3 



I 



OH S C CH3 



^ / / 

 CH2C-N-CH-CH 

 I \ 

 0=^C N CHCO2H 



CH3 

 I 

 O H S CCH3 



K^ / / 

 = CH3 (CH2)6C-N-CH-CH 

 I \ 

 0=C N CHCO2H 



In accordance with the nomenclature employed in the forthcoming 

 monograph on the chemistry of penicillin, which is being prepared 

 under the auspices of the National Academy of Sciences, penicillin G is 

 designated benzylpenicillin j penicillin K, F, and X are designated, re- 

 spectively, ;?-heptylpenicillin, A"-pentenylpenicillin, and ^-hydroxy- 

 benzylpenicillin. 



