482 C. A. West 



lactone ring in the newly proposed structure, you obtain an alco- 

 holic group allylic to a double bond. Such alcoholic groups migrate 

 extremely easily and by such a rearrangement in this case you obtain 

 a product with adjacent alcoholic hydroxyl groups which can reduce 

 periodate as observed. (The Japanese had suggested that some rear- 

 rangement does occur during basic hydrolysis.) So there is a good 

 chemical explanation consistent with the periodate data. 



Dr. Crosby: Actually, I have only one comment to make. I think 

 that those who are not familiar with complicated chemical structures 

 ought to be reminded that this picture that we draw of gibberellic 

 acid actually bears no resemblance to the way that gibberellic acid 

 looks in space. Work is going on in a number of laboratories now 

 to try to determine more closely how this material actually does look. 

 I'm afraid that many of us may be misled if we continue to think of 

 the chemistry of gibberellic acid and the other gibberellins in terms 

 of symmetrical drawings that we can make on a blackboard or on a 

 piece of paper, when actually the configurations are not like that at 

 all. My point is, of course, that when we wish to relate chemistry to 

 growth promoting activity, any previous ideas of these correlations 

 which we have obtained with simple planar structures that we could 

 write on a blackboard may not be adequate for spatially-complex sub- 

 stances such as gibberellic acid. 



