Hemiasterlin analogs

A compound or pharmaceutically acceptable salt thereof, having the formula:

• wherein:
• R1 and R2 are independently selected from the group consisting of:
• H, R, and ArR—, and where at least one of R1 and R2 is R the other is not ArR—;
• R1 and R2 together may optionally be a three to seven member non-aromatic ring;
• R3 and R4 are independently selected from the group consisting of:
• H, R, and ArR—, and where at least one of R3 and R4 is R the other is not ArR, R3 and R4 together may optionally be a three to seven member non-aromatic ring;
• R5 is selected from the group consisting of:
• H, R, ArR—, and Ar;
• R6 is selected from the group consisting of:
• H, R, and ArR—;
• R7 and R8 are independently selected from the group consisting of:
• H, R, and ArR—;
• and
• R9 is:
• and wherein,
• R is defined as a saturated or unsaturated moiety having a linear, branched, or non-aromatic cyclic skeleton containing one to ten carbon atoms, zero to four nitrogen atoms, zero to four oxygen atoms, and zero to four sulfur atoms, and the carbon atoms are optionally substituted with:
• ═O, ═S, —OH, —OR10, —O2CR10, —SH, —SR10, —SOCR10, —NH2, —NHR10, —N(R10)2, —NHCOR10, —NR10COR10, —I, —Br, —Cl, —F, —CN, —CO2H, —CO2R10, —CHO, —COR10, —CONH2, —CONHR10, —CON(R10)2, —COSH, —COSR10, —NO2, —SO3H, —SOR10, —SO2R10, wherein R10 is a linear, branched or cyclic, one to ten carbon saturated or unsaturated alkyl group,
• X is defined as a moiety selected from the group consisting of:
• —OH, —OR, ═O, ═S, —O2CR, —SH, —SR, —SOCR, —NH2, —NHR, —N(R)2, —NHCOR, —NRCOR, —I, —Br, —Cl, —F, —CN, —CO2H, —CO2R, —CHO, —COR, —CONH2, —CONHR, —CON(R)2, —COSH, —COSR, —NO2, —SO3H, —SOR, and —SO2R;
• Ar is an aromatic ring selected from the group consisting of:
• phenyl, naphthyl, anthracyl, phenanthryl, furyl, pyrrolyl, thiophenyl, benzofuryl, benzothiophenyl, quinolinyl, isoquinolyl, imidazolyl, thiazolyl, oxazolyl, and pyridinyl, optionally substituted with R or X;
• Y is a linear, unsaturated, one to six carbon alkyl group, optionally substituted with R, ArR—, or X;
• and
• Z is defined as a moiety selected from the group consisting of:
• —NHR;
• and —N(R)2.