Purity >98% by NMR, TLC. KL-001 is a novel tool that specifically interacts with cryptochrome (CRY) preventing its ubiquitin-dependent degradation resulting in lengthening of the circadian period. KL-001-mediated CRY stabilization inhibits glucagon-induced gluconeogenesis in primary hepatocytes. Binds to the FAD-binding pocket of CRY2 as determined by co-crystal structure. KL-001 induces an increase in period along with simultaneous reduction in amplitude of circadian reporter expression in mammalian cells.