(3R,4S)-Tofacitinib (Tofacitinib Impurity A) is a less active diastereomer/enantiomer of Tofacitinib (CP 690550; tasocitinib; Xeljanz), which is a JAK3 (Janus-Associated kinase) inhibitor and an FDA approved drug for the treatment of rheumatoid arthritis (RA), psoriatic arthritis, and ulcerative colitis.

纯度：≥98%

CAS：1092578-46-5