[Concepts for the synthesis of new biologically active substances].

Three concepts for the synthesis of biologically active compounds are discussed and illustrated by examples. In addition to the accidental finding of biologically active compounds, synthesized purely for chemical reasons, analogy models can serve as guidelines for synthesis. In the latter, naturally occurring or synthetic biologically active molecules are modified to optimize or alter the biological properties. A third approach for the synthesis of active substances is oriented according to the side of action. Models from biochemistry and molecular biology serve as a basis for synthesis planning.