JAK3 inhibitors of imidazopyridazine and their use for the treatment of inflammatory and autoimmune diseases

A compound having the formula II: Formula ** ** or a stereoisomer or a pharmaceutically acceptable salt thereof, wherein: R1a is independently at each occurrence H, F, Cl, Br, - (CH2) r OR b, alkyl C1-6 substituted with 0-5 Ra or - (CH2) r-3-6 membered carbocyclic substituted with 0-2 Ra; R1b is hydrogen, - (CH2) rC (O) R1d, - (CH2) rC (O) OR b, - (CH2) rS (O) 2R, C1-6 alkyl substituted with 0-2 R a - (CH2) r-heterocycle -5-7 membered heterocycle comprising carbon atoms and 1-4 heteroatoms selected from N, O and S (O) p substituted with 0-2 r; or - (CH2) r-5-7 membered heteroaryl comprising carbon atoms and 1-4 heteroatoms selected from N, O and S substituted with 0-2 R; R1d is independently each occurrence hydrogen, C1-6 alkyl substituted with 0-2 Rd, C1- 6 haloalkyl, C (O) NRcRc, C3-6 cycloalkyl substituted with 0-2 Rd, or (CH2) r-phenyl substituted with 0-2 Ra, a heterocycle of 4 to 10 members containing 1-4 heteroatoms selected from N, O and S, substituted with 0-3 Ra; R2 is selected from: