Highly selective Janus kinase 3 inhibitors based on a pyrrolo[2,3-d]pyrimidine scaffold: evaluation of WO2013085802

A series of pyrrolo[2,3-d]pyrimidine derivatives have previously been claimed as Janus kinase (JAK) 1 selective inhibitors. Introduction of a 4-aryl substituent onto this bicyclic scaffold modulates the JAK selectivity profile, thus providing JAK3 selective inhibitors. This patent application claims such compounds as JAK3 inhibitors. Many of the compounds exemplified show > 100,000-fold selectivity for JAK3 over JAK2. The inhibitors are claimed to be useful in the treatment of respiratory diseases, arthritis and cancer.