A compound having a structure of Formula: as an isolated stereoisomer or a mixture of stereoisomers or as a pharmaceutically acceptable salt thereof, wherein: R 1 is substituted pyridinyl having one or more substituents independently selected from: cycloalkyl and C 1-12 alkyl; substituted indolyl having one or more substituents independently selected from: phenyl, substituted phenyl, substituted benzyl, pyridinyl, sulfonyl, acetyl, acyl, carbonyl, C 1-12 alkyl, acyloxy C 1-12 alkyl, C 1-12 alkoxy, halogen, monoxide, and cyano, wherein the substituted benzyl is nitro-benzyl, or amino- benzyl, wherein the sulfonyl is selected from the group consisting of tosyl, phenyl sulfonyl, C 1-12 alkyl sulfonyl, C 1-12 alkylsulfonylamino, aminosulfonylamino or halo-phenyl sulfonyl, wherein the carbonyl is selected from the group consisting of cycloalkylcarbonyl, C 1-12 alkoxycarbonyl, morpholinylcarbonyl, aminocarbonyl, C 1-12 alkylaminocarbonyl, di C 1-12 alkylaminocarbonyl, C 1-12 alkynylaminocarbonyl, C 2-13 alkoxyalkylaminocarbonyl thiophenyl C 1-12 alkylaminocarbonyl, benzylaminocarbonyl, dihydropyrrolylcarbonyl, cycloalkyl C 1-12 alkylcarbonyl, cycloalkenyl C 1-12 alkylcarbonyl, C 2-13 alkoxyalkylcarbonyl, imidazolylaminocarbonyl, piperidinylcarbonyl, pyrrolidinylcarbonyl, alkoxyaminocarbonyl, hydroxyaminocarbonyl, hydroC 1-12 alkylaminocarbonyl, hydrazinylcarbonyl, C 1-12 alkylformatehydrazinylcarbonyl, or tetrahydrofuranylC 1-12 alkylaminocarbonyl; R 4 is allyl; R 6 is phenyl or substituted phenyl having one or more substituents independently selected from: halogen, hydroxyl, cyano, C 1-6 alkyl and C 1-6 alkoxy; or pyridyl or substituted pyridyl having one or more substituents independently selected from: halogen, hydroxyl, cyano, C 1-6 alkyl and C 1-6 alkoxy; X 1 is hydrogen, hydroxyl or halogen; and each of X 2 and X 3 is independently hydrogen, hydroxyl, dimethylaminoacetate, (2-dimethylamino-ethyl)-carbamate, diethyl-phosphono-acetamido or halogen, wherein the alkyl is a straight or branched, saturated or unsaturated hydrocarbon chain radical including monocyclic or bicyclic hydrocarbon, which includes fused or bridged ring systems, wherein the cycloalkyl is a monocyclic or bicyclic hydrocarbon ring radical, which includes fused or bridged ring systems. R 1 is substituted pyridinyl having one or more substituents independently selected from: cycloalkyl and C 1-12 alkyl; substituted indolyl having one or more substituents independently selected from: phenyl, substituted phenyl, substituted benzyl, pyridinyl, sulfonyl, acetyl, acyl, carbonyl, C 1-12 alkyl, acyloxy C 1-12 alkyl, C 1-12 alkoxy, halogen, monoxide, and cyano, wherein the substituted benzyl is nitro-benzyl, or amino- benzyl, wherein the sulfonyl is selected from the group consisting of tosyl, phenyl sulfonyl, C 1-12 alkyl sulfonyl, C 1-12 alkylsulfonylamino, aminosulfonylamino or halo-phenyl sulfonyl, wherein the carbonyl is selected from the group consisting of cycloalkylcarbonyl, C 1-12 alkoxycarbonyl, morpholinylcarbonyl, aminocarbonyl, C 1-12 alkylaminocarbonyl, di C 1-12 alkylaminocarbonyl, C 1-12 alkynylaminocarbonyl, C 2-13 alkoxyalkylaminocarbonyl thiophenyl C 1-12 alkylaminocarbonyl, benzylaminocarbonyl, dihydropyrrolylcarbonyl, cycloalkyl C 1-12 alkylcarbonyl, cycloalkenyl C 1-12 alkylcarbonyl, C 2-13 alkoxyalkylcarbonyl, imidazolylaminocarbonyl, piperidinylcarbonyl, pyrrolidinylcarbonyl, alkoxyaminocarbonyl, hydroxyaminocarbonyl, hydroC 1-12 alkylaminocarbonyl, hydrazinylcarbonyl, C 1-12 alkylformatehydrazinylcarbonyl, or tetrahydrofuranylC 1-12 alkylaminocarbonyl; R 4 is allyl; R 6 is phenyl or substituted phenyl having one or more substituents independently selected from: halogen, hydroxyl, cyano, C 1-6 alkyl and C 1-6 alkoxy; or pyridyl or substituted pyridyl having one or more substituents independently selected from: halogen, hydroxyl, cyano, C 1-6 alkyl and C 1-6 alkoxy; X 1 is hydrogen, hydroxyl or halogen; and each of X 2 and X 3 is independently hydrogen, hydroxyl, dimethylaminoacetate, (2-dimethylamino-ethyl)-carbamate, diethyl-phosphono-acetamido or halogen, wherein the alkyl is a straight or branched, saturated or unsaturated hydrocarbon chain radical including monocyclic or bicyclic hydrocarbon, which includes fused or bridged ring systems, wherein the cycloalkyl is a monocyclic or bicyclic hydrocarbon ring radical, which includes fused or bridged ring systems.