Enaminones push-pull conjugation

X-ray determinations of the molecular structures of thirteen / -enaminones 84 to 96 with the formal possibility of push-pull conjugation and the formulae shown in Scheme 3 cover the range of tertiary 84 to 86, and 89 to 92, secondary 87,88 and 93, and primary 94 to 96 / -keto enamines. Relevant distances are given in Table 1 and angles in Table 2. 

In push-pull substituted / -enaminones 84 to 87 due to through conjugation the C=C distance is elongated to about 1.380 A. In other push-pull systems 99 to 103 the C=C bond lengths are in the range of 1.348 to 1.405 A. In both classes the C—N distances vary between 1.303 and 1.390 A. 

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