Tautomer Ratio in the Imine-Enamine System Substitution at Nitrogen

Tautomer Ratio in the imine-Enamine System Substitution at Nitrogen 

Since nitrogen tautomerism in 15 resembles in formal structure that of an amidine such as 14 it might be expected to follow similar rules. However, it does not. 

The effect of R = phenyl maybe studied via the fused ring compounds 21 and 27, using the same reasoning as for 16 above. Katritzky and coworkers [13b] measured 

8 for 22 and, because its molecular skeleton is close to that of 21 regarded it as a good model for the latter, with which we concur. The nearest model for 27 is 23, 7.9 [13b], but this lacks the essential 2-methyl substituent. If the 

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