Covalent Fragments Smart Library
Drug design of small molecules is based on their ability to interact with their biological targets under equilibrium binding states. These binding states occur in a fast and reversible process, which affects the duration of the therapeutic response. Thus, prolongation of therapeutic response can be extended by increasing the duration of interaction between a drug and its target. This type of prolonged interaction can be achieved by covalent inhibitors. Covalent inhibitors bind to their target in two steps, starting with equilibrium bond formation, and ending with covalent bond formation. The final state is considered to be irreversible, resulting in a drug–protein complex that is different from that formed with a normal equilibrium bond. The covalent bond can be either reversible or irreversible, depending on the chosen warhead. A number of different warheads have been exploited to target specific amino acid residues, including among others cysteine, serine, threonine, tyrosine and lysine. 
ChemDiv offers the smart library of covalent inhibitors. The main criteria for members selections are:
1) Should be rationally designed as members of Smart LCI
2) Core structures (including warhead) should meet the criteria applied for the general fragment library.
 F. Sutanto, M. Konstantinidou, and A. Dömling, “Covalent inhibitors: A rational approach to drug discovery,” RSC Med. Chem., vol. 11, no. 8, pp. 876–884, 2020, doi: 10.1039/d0md00154f.