or a pharmaceutically acceptable salt thereof, wherein

Ar^a is phenyl or thienyl;

R⁶ is H, or C₁-C₆-alkyl;

Y and Z are —CH═;

W is (V′-L⁴)_t-V-L³-;

L³ is a direct bond, —C₁-C₆-hydrocarbyl, —(C₁-C₃-hydrocarbyl)_m1-X′—(C₁-C₃-hydrocarbyl)_m2, —NH—(C₀-C₃-hydrocarbyl), (C₁-C₃- hydrocarbyl)-NH—, or —NH—(C₁-C₃-hydrocarbyl)-NH—;

m1 and m2 are independently 0 or 1;

X′ is —N(R²¹)—, —C(O)N(R²¹)—, N(R²¹)C(O)—, —O—, or —S—;

 R²¹ is —H, V″—(C₁-C₆-hydrocarbyl)_c;

L⁴ is (C₁-C₆-hydrocarbyl)_a-M-(C₁-C₆-hydrocarbyl)_b;

a and b are independently 0 or 1;

M is —NH—, —NHC(O)—, —C(O)NH—, —C(O)—, —SO₂—, —NHSO₂—, or —SO₂NH—

V, V′, and V″ are independently selected from cycloalkyl, heterocyclyl, aryl, and heteroaryl;

t is 0 or 1;

or W, the annular C to which it is bound, and Y together form a monocyclic cycloalkyl, heterocyclyl, aryl, or heteroaryl; and

wherein the A and Ar^a rings are optionally further substituted with from 1 to 3 substituents independently selected from methyl, hydroxy, methoxy, halo, and amino.