Hydrogen bond complementarity

The preparation of 2-hydroxy-3 -pyridinecarboxaldehyde and its 6-acetamido derivative, and their condensation with Fischer s base to give the corresponding spiropyridopyrans have been described. The acetamido spiro compound selectively recognizes guanine, which traps the open colored form by triple hydrogen bond complementarity, thus signaling the presence of guanosine derivatives.79... 

The design of the spiropyridopyran 14a (Figure 12) was based on the triple hydrogen-bond complementarity between the acetamidopyridopyran unit of 14a or the acetamidopyridone anion unit of the open merocyanine form 14a and guanine. We expected that the equilibrium between the colorless spiropyridopyran and the colored merocyanine would be shifted toward the latter by recognition of... 

Figure 7.6 Molecular models of the DNA base pairs Illustrating Watson-Crick hydrogen bonding complementarity.

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