Pyrimidine compounds as JAK kinase inhibitors

A method of treating a gastrointestinal inflammatory disease selected from the group consisting of collagenous colitis, lymphocytic colitis, Behcet's disease, ileitis, eosinophilic esophagitis, graft versus host disease-related colitis, Crohn's disease, celiac disease, ulcerative colitis, immune checkpoint inhibitor induced colitis and infectious colitis, in a mammal, the method comprising administering to the mammal a compound of formula (I):

• wherein
• R1 is selected from:
• (a) —S(O)2R4, wherein R4 is selected from:
• C1-4alkyl, wherein C1-4alkyl is optionally substituted with CN, —OC1-3alkyl, or C3-6cycloalkyl,
• heterocyclyl containing 4 to 6 ring atoms including one nitrogen atom,
• wherein any heterocyclyl is optionally substituted with CN, C3-6cycloalkyl,
• pyridinyl, wherein pyridinyl is optionally substituted with fluoro, and phenyl;
• (b) C1-4alkyl, wherein C1-4alkyl is optionally substituted with —CN
• or
• pyridinyl, wherein pyridinyl is optionally substituted with —CN;
• and
• (c) —C(O)R5, wherein R5 is selected from:
• C1-4alkyl, wherein C1-4alkyl is optionally substituted with C3-6cycloalkyl, or with one or two fluoro,
• —OC1-4alkyl,
• C3-6cycloalkyl, and
• morpholinyl;
• R2 is hydrogen or methyl;
• R3 is C1-3alkyl;
• and
• n is 1 or 2;
• or a pharmaceutically-acceptable salt thereof.