where Ar¹ is phenyl, pyridyl, pyrimidyl, pyridazinyl, or triazinyl, in which all ring carbon atoms are optionally substituted with substituents R₁, R₂, and R₃, which are selected independently from hydrogen; halogen; hydroxy; nitro; cyano; C₁-C₄ alkyl, optionally substituted with one to three fluorine atoms; CH₃O; 2-methoxy ethenyl; (CH₃)₂N; CH₃OC(O); CH₃CH₂OC(O); NR₇R₈, —C(O)NR₇R₈; or —S(O)₂NR₇R₈, where R₇ and R₈ are, independently, H, CH₃, or CH₃CH₂; and R₁ may also be 2-C(O)K, where K is selected from:

—OJ, where J is isopropyl, cyclopropyl, cyclopentyl, dimethylamino, or methoxyethyl;

—NHJ′ where J′ is methyl, ethyl, isopropyl, cyclopropyl, dimethylaminomethyl, or 3-methyl-2-yl-butanoic acid methyl ester; and

—N(CH₃)₂; or 4-methylpiperzin-1-yl;

or R₁ and R₂ are attached to adjacent carbons and, together with the ring atoms to which they are attached, form an additional, fused, five- or six-membered ring, optionally containing one heteroatom, which ring may be aromatic or aliphatic;

A is O, S, CH₂, N₂, CO, NHCO, COCH₂, or CH₂CO;

or Ar¹-A is

where the five-membered ring is fused to Ar¹ and Y is NH, S, or O;

or Ar¹-A is

where the dotted line represents an optional double bond, the five-membered ring is fused to Ar¹, and R_x is selected from substituents listed above for R₃;

or Ar¹-A is

where the five-membered ring is fused to Ar¹, and R_x is selected from substituents listed above for R₃;

Ar² is phenyl, pyridyl, pyrimidyl, pyridazinyl, or triazinyl, where ring carbon atoms are optionally substituted with substituents R₄-R₆ which are selected independently from H, F, Cl, Br, CH₃, or CF₃;

or Ar²—NH— is

where R_y is selected from substituents listed above for R₃;

and R′ is OH; O—C₁-C₆ alkyl; C₁-C₆ alkyl, said C₁-C₆ alkyl groups optionally substituted with one to three groups selected independently from hydroxy, halogen, C₁-C₃ alkoxy, and phenyl; —CH₂B or —CH₂CH₂B, where B is selected from C_3-7 cycloalkyl, C₇-C₉ bicycloalkyl, pyridyl, piperazinyl, piperidinyl, N-morpholyl, tetrahydrofuryl, and naphthyl; C₃-C₇ cycloalkyl; C₇-C₉ bicycloalkyl, where all cycloalkyl, bicycloalkyl, pyridyl, piperazinyl, piperidinyl, N-morpholyl, tetrahydrofuryl, and naphthyl groups are optionally substituted with one to three groups selected independently from hydroxy, halogen, and methyl;

or R′ is (CH₂)_n-G, where n is 1 or 2 and G is a five- or six-membered ring or a 9-14-membered fused ring system, wherein each ring optionally contains 1-3 heteroatoms selected independently from O, N, and S; wherein each ring is optionally substituted with 1-3 groups selected independently from the following: halogen, hydroxy, cyano, oxo, and C₁-C₄ alkyl, wherein said C₁-C₄ alkyl group is optionally substituted with one to three halogen atoms; and wherein each ring optionally contains one or more double bonds;

or R′ is —CH(CH₂OH)CH₂D, where D is selected from imidazolyl, indolyl, carboxamido, phenyl, cyclohexyl, —CH₂SCH₃, and adamantin-1-yl.