Disclosed are inhibitors of the USP1/UAF1 deubiquitinase complex, for example. of formula (I), wherein R1, R2, and Q are as defined herein, which are useful in treating diseases such as cancer, and improving the efficacy of DNA damaging agents in cancer treatment. Also disclosed is a composition comprising a pharmaceutically suitable carrier and at least one compound of the invention, a method of method of inhibiting a heterodimeric deubiquitinase complex in a cell, and a method of enhancing the chemotherapeutic treatment of cancer in a mammal undergoing treatment with an anti cancer agent. Further disclosed is a method of preparing compounds of the invention.
