A compound of Formula I, enantiomers, diasteriomers, tautomers or pharmaceutically acceptable salts thereof, wherein R1, R2 and R3 are defined herein, are useful as inhibitors of one or more Janus kinases. A pharmaceutical composition that includes a compound of Formula I and a pharmaceutically acceptable carrier, adjuvant or vehicle, and methods of treating or lessening the severity of a disease or condition responsive to the inhibition of a Janus kinase activity in a patient are disclosed.