It is not enough to do indiscriminate synthesis of new chemicals to find new drugs. For example, at the time of combinatorial chemistry, a myriad of chemicals could (and can) be synthesized. However, most of the time, without the necessary drug-like characteristics. The main reason for this is the lack of properties adjusted to the desired chemical space such as molecular mass (MM), lipophilia (as logP) and polar surface area (PSA). An extra problem concerns the search for substances free from stereogenic centers which, if neglected, may well lose the natural cunning of the L world. Of course, there are recognized exceptions.
Considering that chemical space can be the universe (see here), it is better to think appropriately how to construct it using, for example, our strategy in molecular planning based on hypotheses (see here and here). In our hypotheses, however, there are some difficult syntheses to do. Perhaps, however, that is why we are taking off to a space of success. Stairway to success is leaning and requires an efficient cycle of plan-synthesize-test-analyze-plan! Repeat the cycle. Then, subnanomolar inhibitors of cysteine proteases appear and some of them kill Trypanosoma cruzi.
Although we are focused on the druggable chemical space, we are attentive to its neighbors.