Isoxazole compositions useful as inhibitors of ERK

A compound of formula I:

• or a pharmaceutically acceptable salt thereof, wherein:
• Ht is pyrrol-3-yl;
• said pyrrol-3-yl having R3 and QR4 substituents;
• A—B is N—O or O—N;
• R1 is hydrogen or NHR;
• T is a valence bond;
• Q is —C(O)— or —SO2—;
• each R is independently selected from hydrogen or an optionally substituted aliphatic group having one to six carbons;
• R2 is an aryl group substituted with up to three R8 substituents;
• R3 is hydrogen;
• R4 is —NHR6;
• R6 is —(CH2)yCH(R7)2;
• y is 0-6;
• each R7 is independently selected from R, aryl, or hydroxyalkyl, wherein said aryl ring is optionally substituted with halogen, R′, OR′, CO2R′, or SO2R′, wherein each R′ is independently selected from hydrogen or a C1-6 aliphatic group;
• and
• each R8 is independently selected from halogen, —R′, or —OR′;
• wherein each R′ is independently selected from hydrogen or an optionally substituted aliphatic group.