Enumerable Libraries and Accessible Chemical Space in Drug Discovery

In this chapter, enumerable libraries and accessible chemical space are discussed with a focus on different methods to generate chemical space and its application in drug discovery. Additionally, this chapter discusses the methodologies and makeup of a number of public and commercial chemical libraries. The most popular method of chemical space exploration is through the use of reaction-based enumeration in combination with both commercial and in-house reactant libraries. By combining several large vendor libraries, a virtual screening database of more than 24 billion unique molecules was assembled, followed by calculation of its physicochemical properties, and their respective distributions were investigated.