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DISCUSSION 



I)k. Bkssman: I would like to ask Dr. Raslia what is significant about the 

 two and six positions of the substituted pyrimidincs which make them 

 unicjuely interesting. 



Dr. Kasha: I was only suggesting that the Uber and Winter results on 

 the 2,6-dichloropyrimidine have some bearing on thymine, whicli has keto 

 groups in the 2 and (i positions. On the other hand, I didn't have time to 

 discu.ss tautfjmerism of the bases which is extremely important in terms of the 

 origin of the n -^ tt* transitions. It is important because as one tautomerizes. 



