(2R,5S)-Ritlecitinib (2R,5S)-PF-06651600) is a potent and specific JAK3 conjugate (IC50=144.8 nM). For more details, check and find patent US20150158864A1, Example 68.

Physicochemical Properties

Molecular Formula	C15H19N5O
Exact Mass	285.158
CAS #	1792180-79-0
Related CAS #	Ritlecitinib;1792180-81-4
PubChem CID	118116220
Appearance	White to light yellow solid
LogP	2.1
Hydrogen Bond Donor Count	2
Hydrogen Bond Acceptor Count	4
Rotatable Bond Count	3
Heavy Atom Count	21
Complexity	402
Defined Atom Stereocenter Count	2
SMILES	C[C@@H]1CC[C@@H](CN1C(=O)C=C)NC2=NC=NC3=C2C=CN3
InChi Key	CBRJPFGIXUFMTM-MNOVXSKESA-N
InChi Code	InChI=1S/C15H19N5O/c1-3-13(21)20-8-11(5-4-10(20)2)19-15-12-6-7-16-14(12)17-9-18-15/h3,6-7,9-11H,1,4-5,8H2,2H3,(H2,16,17,18,19)/t10-,11+/m1/s1
Chemical Name	1-[(2R,5S)-2-methyl-5-(7H-pyrrolo[2,3-d]pyrimidin-4-ylamino)piperidin-1-yl]prop-2-en-1-one
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month Note: This product requires protection from light (avoid light exposure) during transportation and storage.
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

Targets	JAK3 (IC50 = 145 nM)
ln Vitro	Ritlecitinib is a powerful JAK3-selective inhibitor that has an IC50 of 33.1 nM for inhibiting JAK3 kinase activity, but no activity (IC50>10,000 nM) against JAK1, JAK2, and TYK2. With IC50 values of 244, 340, 407, and 266 nM, respectively, ritlecitinib suppresses the phosphorylation of STAT5 induced by IL-2, IL-4, IL-7, and IL-15. With an IC50 of 355 nM, ritlecitinib also prevents IL-21-induced STAT3 phosphorylation. Ritlecitinib inhibits Th1 and Th17 differentiation (measured by IFNγ after 5 days under Th1 circumstances and IL-17 production after 6 days under Th17 settings) in T-cell differentiation assays, according to functional assessment (IC50 values: 30 nM and 167 nM, respectively). Additionally, ritlecitinib inhibits Th1 and Th17 function as demonstrated by the suppression of IFNγ production (IC50=48 nM) and IL-17 production (IC50=269 nM) in cells that have undergone prior differentiation and resting before PF-06651600 treatment[1].
ln Vivo	Ritlecitinib reduces paw swelling in the rat adjuvant-induced arthritis (AIA) model, with an unbound EC50 of 169 nM. In the experimental autoimmune encephalomyelitis (EAE) mouse model, ritlecitinib, administered either therapeutically at 30 or 100 mg/kg or prophylactically at 20 or 60 mg/kg, significantly reduces the severity of the disease. Ritlecitinib's effectiveness in treating inflammatory and autoimmune diseases in these two rodent models shows that JAK3-selective inhibition alone may be enough to modify disease in humans[1].
References	[1]. Telliez JB, et al. Discovery of a JAK3-Selective Inhibitor: Functional Differentiation of JAK3-Selective Inhibition over pan-JAK or JAK1-Selective Inhibition. ACS Chem Biol. 2016 Dec 16;11(12):3442-3451. [2]. Atli Thorarensen, et al. Pyrrolo[2,3-d]pyrimidinyl, pyrrolo[2,3-b]pyrazinyl and pyr-rolo[2,3-d]pyridinyl acrylamides. US20150158864A1.

Solubility Data

Solubility (In Vitro)

DMSO : ~220 mg/mL (~771.01 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 5.5 mg/mL (19.28 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 55.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. Solubility in Formulation 2: ≥ 5.5 mg/mL (19.28 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 55.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly. Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution. Solubility in Formulation 3: ≥ 5.5 mg/mL (19.28 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 55.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.  (Please use freshly prepared in vivo formulations for optimal results.)