Inhibitors of cysteine proteases and methods of use thereof

A compound represented by Formula I:

• or a pharmaceutically acceptable salt or stereoisomer thereof, wherein:
• R25 is —C(O)R1,
• R1 is 4-7 membered heterocyclyl, wherein R1 is optionally substituted by one, two or three substituents each selected from Ra,
• R2 is C6-C14aryl, wherein R2 is optionally substituted by one, two or three substituents each selected from R5;
• wherein C6-C14aryl may optionally be fused with one or more carbocyclyl or heterocyclyl groups, and wherein C6-C14aryl designates the number of carbon atoms in the aryl ring system;
• R3 is 5-6 membered monocyclic heteroaryl, wherein the 5-6 membered monocyclic heteroaryl contains at least one ring nitrogen and may have one, two or three optional substituents each selected from Ra;
• R3a is selected from the group consisting of hydrogen and C1-C6alkyl;
• R4 is selected from the group consisting of C3-C10cycloalkyl and C1-C6alkyl-(C6-C14aryl), wherein the C3-C10cycloalkyl is optionally substituted by one, two or three substituents each selected from Ra;
• R4a is hydrogen;
• R5 is independently selected, for each occurrence, from the group consisting of halogen, SF5, C1-C6alkyl, C3-C10cycloalkyl, and C6-C14aryl;
• Ra is independently selected, for each occurrence, from the group consisting of halogen, hydroxyl, cyano, —ORaa, C1-C6alkyl, C1-C6haloalkyl, and C1-C6alkoxy;
• and
• Raa is C1-C6haloalkyl.