Biologically active substances, dynamic

Lehn and coworkers reported a series of reactive diene and pentafulvenes involving reversible Diels-Alder reactions at ambient temperature. The results provide a foundation for the implementation of the reversible Diels-Alder reaction in constitutional dynamic chemistry (Scheme 7.26) [27]. With variation of the functionalized substituted fulvenes 108 and cyanoolefin esters 109, the methodology may be applied for the preparation of dynamic combinatorial libraries and provides an entry to reversible dynamic polymers and the discovery of biologically active substances. 

Ultimately, the potential ofbiologically active substances can only be assessed in actual biological systems by means of animal experiments (Scheme 1-29) and confirmed by subsequent clinical studies. En route to this, however, the dynamic system described here offers various options for the analysis and optimization of pharmacological parameters like affinity and activity. It is the heterobifunctional character of the dynamic system that allows the synthetic chemist to influence both intrinsic self-assembly as well as extrinsic molecular recognition in a controlled way. 

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