WHI-P154, 10 mg

This small-molecule inhibitor of Janus kinase 3 (JAK3) is supplied by STEMCELL Technologies as a crystalline solid. The chemical name is 2-bromo-4-[(6,7-dimethoxyquinazolin-4-yl)amino]phenol (CAS 211555-04-3), with the molecular formula C₁₆H₁₄BrN₃O₃ and a molecular weight of 376.2 g/mol. Synonyms listed for the compound include JAK3 Inhibitor II and Janus-Associated Kinase 3 Inhibitor II, and the product is supplied at a purity of ≥ 98%.

It inhibits JAK3 with IC₅₀ values of 28 and 128 µM against human and mouse protein, respectively. The compound has also been reported to show significant inhibition of other kinases, including epidermal growth factor receptor (EGFR) in the nanomolar range, while no significant inhibition of JAK1 or JAK2 has been observed. Reported solubility values are ~0.5 mg/mL in a 1:1 DMF:PBS (pH 7.2), ~15 mg/mL in DMSO, and ~25 mg/mL in DMF. The product is stable at -20 °C as supplied and should be protected from prolonged exposure to light.

Published applications include promotion of differentiation of mouse neuronal precursor cells to neurons and oligodendrocytes while blocking astrocyte differentiation, abolition of PDGF-induced increases in neurite outgrowth from human neural progenitor cells, inhibition of lipopolysaccharide (LPS)-induced nitric oxide synthase expression and nitric oxide production in macrophages and human epithelial cells, and induction of apoptosis and cell death in human glioblastoma cell lines U373 and U87. The compound is classified as hazardous under GHS with Acute Toxicity: Oral (Category 3), Skin Corrosion/Irritation (Category 2), Serious Eye Damage/Eye Irritation (Category 2), and Target Organ Systemic Toxicity (single exposure, Category 3).