Organic building blocks are organic molecules that are well furnished, the basic components for organic synthesis. They are used for molecular architectures such as organic molecular constructs, supramolecular complexes, metal-organic frameworks and nanoparticles. In medicinal chemistry, they are selected for the use in modular synthesis of drug candidates. And organic building blocks should be equipped with one or more handles so that they can be experimentally useful for the modular drug or drug candidate assembly.
Medicinal chemistry and pharmaceutical research remain solely reliant on synthetic chemistry methodologies and therefore demand diverse chemical building blocks offer meeting strict requirements in terms of not only physicochemical properties but also chemical reactiveness. The search for new leads and the following structural optimization is also critical for pharmaceutical industry. However, it is assumed that the chemical space exceeds 1060 molecules, and it is impossible for mankind to make all of those molecules, so far, only about 27 million compounds have been registered. In this case, the analysis of common scaffolds and side chains of drug molecules is particularly useful when it comes to the design of combinatorial libraries. Building block selections that are composed of drug-like building blocks containing side chains and scaffolds of known drugs can greatly enhance the possibility of increased hit rates in bioactive screening.
Traditionally, natural products screening, pharmacological and professional knowledge have been the major source for lead discovery. However, during the last 10 years combinatorial chemistry, along with high-throughput screening (HTS), has developed as a new route to drug discovery. In combinatorial chemistry a large library of compounds is synthesized, as combinations of building blocks . With a large building block library in hand, these molecules are tested for biological activity by HTS, with the scope to identify a novel central structure that corresponds to a receptor, an enzyme, or any other molecular target of interest.
With the advances of combinatorial chemistry and high throughput screenings (HTS), obtaining one or several inhibitors is not very difficult for some protein targets in drug discovery. However, the challenge of choosing proper drug leads to optimize and turning promising drug candidates into real drugs is still arduous. The pragmatic way to improve the quality of both candidate drugs and screening collections is by improving the quality of the building blocks that are used to synthesize them.
In conclusion, the building blocks which is developable, expandable and optimizable will greatly accelerate the screening of new drugs. The careful analysis of the building blocks in the current medicine skeletons will also inspire the discovery of novel pharmaceutical compounds in turn.