While the molecules in the validation set represent many of the functional groups often used in drug design, they contain many fewer rotatable dihedral bonds and functional groups than a typical drug-like molecule. Thus, following previous work investigating the use of QM derived FF parameters we have used QUBEKit to derive a QUBE FF for 3-hydroxypropionic acid (3-HA). The molecule shown in Figure incorporates carboxyl and hydroxyl functional groups, has been identified as a potentially useful agent for organic synthesis and is also a surrogate for a typical fragment scaffold. QM-based fitting techniques have previously been used to derive the bonded parameters for the molecule from a series of single point energy calculations, with the L-J terms being taken from AMBER and the partial charges assigned according to the CHelpG scheme. In addition, we have selected two further molecules from the FreeSolv database, which allows us to compare computed hydration free energies with experiment for more challenging small drug-like molecules. The two molecules, captan and bromacil (Figure ), were selected due to the presence of halogens, and they therefore provide an additional test of the virtual site assignment procedure in QUBE.