Pyrazole derivatives as inhibitors of stat3

A compound of Formula IA:

• or a pharmaceutically acceptable salt thereof, wherein:
• R3 is selected from C1-10 alkyl, C2-6 alkenyl, C2-6 alkynyl, C6-12 aryl, C5-12 heteroaryl, C3-12 cycloalkyl, C3-10 heterocycloalkyl, and (CH2)p—R5, wherein said C1-10 alkyl, C2-6 alkenyl, C2-6 alkynyl, C6-12 aryl, C5-12 heteroaryl, C3-12 cycloalkyl, or C3-10 heterocycloalkyl is optionally substituted with 1, 2, 3, 4, or 5 substituents selected from halo, CN, NO2, ORa1, SRa1, C(O)Rb1, C(O)NRc1Rd1, C(O)ORa1, OC(O)Rb1, OC(O)NRc1Rd1, NRc1Rd1, NRc1C(O)Rb1, NRc1C(O)(CH2)nO(CH2)mC(O)NRc1Rd1, NRc1C(O)ORa1, NRc1C(O)NRc1Rd1, NRc1S(O)2Rb1, S(O)Rb1, S(O)2Rb1, and S(O)2NRc1Rd1;
• R2 is H, C1-10 alkyl, or C1-6 haloalkyl;
• R4 is selected from NRc2Rd2, C1-10 alkyl, C1-6 haloalkyl, C2-6 alkenyl, C2-6 alkynyl, aryl, cycloalkyl, heteroaryl, and heterocycloalkyl, wherein said C1-10 alkyl, C2-6 alkenyl, C2-6 alkynyl, aryl, cycloalkyl, heteroaryl, or heterocycloalkyl is optionally substituted with 1, 2, or 3 substituents independently selected from OH, C1-6 alkoxy, CN, amino, alkylamino, dialkylamino, halo, C1-6 alkyl, C1-6 haloalkyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl, cycloalkyl, and heterocycloalkyl;
• R5 is C6-12 aryl, optionally substituted with 1, 2, 3, 4, or 5 substituents selected from NRc1Rd1, NRc1C(O)Rb1, NRc1C(O)(CH2)nO(CH2)mC(O)NRc1Rd1, NRc1C(O)ORa1, NRc1C(O)NRc1Rd1, and NRc1S(O)2Rb1;
• Ra1 is selected from H, C1-6 alkyl, C1-6 haloalkyl, C2-6 alkenyl, C2-6 alkynyl, aryl, cycloalkyl, heteroaryl, heterocycloalkyl, arylalkyl, heteroarylalkyl, cycloalkylalkyl, and heterocycloalkylalkyl, wherein said C1-6 alkyl, C1-6 haloalkyl, C2-6 alkenyl, C2-6 alkynyl, aryl, cycloalkyl, heteroaryl, heterocycloalkyl, arylalkyl, heteroarylalkyl, cycloalkylalkyl, or heterocycloalkylalkyl is optionally substituted with 1, 2, or 3 substituents independently selected from OH, CN, amino, halo, C1-6 alkyl, C1-6 alkoxy, C1-6 haloalkyl, and C1-6 haloalkoxy;
• Rb1 is selected from H, C1-6 alkyl, C1-6 haloalkyl, C2-6 alkenyl, C2-6 alkynyl, aryl, cycloalkyl, heteroaryl, and heterocycloalkyl, wherein said C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl, aryl, cycloalkyl, heteroaryl, or heterocycloalkyl is optionally substituted with 1, 2, or 3 substituents independently selected from OH, C1-6 alkoxy, CN, amino, alkylamino, dialkylamino, halo, C1-6 alkyl, C1-6 haloalkyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl, cycloalkyl, and heterocycloalkyl;
• Rc1, Rc2, Rd1, and Rd2 are independently selected from H, C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl, aryl, cycloalkyl, heteroaryl, and heterocycloalkyl, wherein said C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl, aryl, cycloalkyl, heteroaryl, or heterocycloalkyl is optionally substituted with 1, 2, or 3 substituents independently selected from OH, C1-6 alkoxy, CN, amino, alkylamino, dialkylamino, halo, C1-6 alkyl, C1-6 haloalkyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl, cycloalkyl, and heterocycloalkyl;
• or,
• Rc1 and Rd1, or Rc2 and Rd2, together with the N atom to which they are attached, may optionally form a 4-, 5-, 6-, or 7-membered heterocycloalkyl group or heteroaryl group, each optionally substituted with 1, 2, or 3 substituents independently selected from OH, C1-6 alkoxy, CN, amino, alkylamino, dialkylamino, halo, C1-6 alkyl, C1-6 haloalkyl, aryl, arylalkyl, heteroaryl, heteroarylalkyl, cycloalkyl, and heterocycloalkyl;
• and
• m, n, and p are independently 1, 2, or 3.