68 



ROLAND FISCHER 



H5C0 



X 



./ 



NCH 2 CH 2 C1 

 CH 2 • CH 3 



CH, CH 2 



CH, CH, 



\ / 



N- 



H 6 C, 



SKF-501 Ethylenimonium form of SKF-501 



Mol. weight: 314 



C atoms (up to 4) between the primary amino group(s) and the neighboring N 

 of the nucleus, (d) the presence of two hidden "LSD-tails" and (e) a molecular 

 weight around 320 appears to be characteristic of basic drugs displaying a high 

 affinity for wool. Some of the aforementioned common structural features of 

 LAE, LSD, methylene blue and SKF-501 remind us that among the phenaz- 

 athionium compounds substitution in the amino group (alkylation) is accom- 

 panied by an increase in basicity; the latter characteristic, however, might be 

 regarded only as one of the factors influencing the affinity of our basic com- 

 pounds for wool (Fischer and Larose, 1952b). 



Since the following data, kindly supplied by the courtesy of Professor E. 

 Rothlin (Basel, Switzerland), indicate that there is no increase in basicity if 

 LAE is compared with LSD: 



pKb in H 2 of Mescaline 4.25 



LAE 7.17 



LSD 7.12 



the higher affinity for wool of the latter appears to be due to other factors. 



Numerous problems as well as questions arise in connection with the above 

 speculations; for example, is the optically active C-atom and its adjacent struc- 

 tural part, the 



C 2 H 5 



* / 



CH— CO— N 



\ 



C0H5 



grouping involved in the highly specific action of LSD? Such questions remind 

 us of the limitations of wool in this study, since (a) wool protein might be re- 

 garded only as a model of the protein component of the target organ(s) playing 



