CHI3L1-IN-2 (Compound 36) is a CHI3L1 (Chitinase-3-Like Protein 1) inhibitor. CHI3L1-IN-2 inhibits the? interaction between CHI3L1 and heparan sulfate (CHI3L1:HSIII), with an IC 50 of 26 nM. CHI3L1, also known as YKL-40, is a glycoprotein associated with inflammation, fibrosis, and cancer.