A compound having Formula I, its enantiomers, diastereoisomers, hydrates, solvates, crystal forms and tautomers or a pharmaceutically acceptable salt thereof: wherein: R 1 is H; R 2 is methyl, isopropyl, 2-hydroxyethyl, hydroxycyclopentyl, ethyl, 2-aminoethyl, H-imidazol-2-ylmethyl, 1H-imidazol-4-ylmethyl, 2-[(aminocarbonyl)amino]ethyl, 6-aminopyridin-2-yl, 2-oxo-1,3-oxazolidin-5-yl-methyl, 2,6-dioxo-1,2,3,6-tetrahydropyrimidin-4-yl)methyl, 3-aminopropyl, 1H-pyrazol-3-ylmethyl, 2-amino-1,3-thiazol-4-yl)methyl, 2-nitrobenzyl, 3-methoxybenzyl, 5-nitro-1H-pyrazol-3-yl-methyl, 5-amino-1H-pyrazol-3-yl-methyl, 1-propyl-1H-imidazol-4-yl)methyl, 3-hydroxybenzyl, 5-amino-4H-1,2,4-triazol-3-yl)methyl, 2-pyridin-2-ylethyl, 2-(1H-pyrazol-4-yl)ethyl, 2-(3,5-dimethyl-1H-pyrazol-4-yl)ethyl, (2-fluoropyridin-3-yl)methyl, trifluoromethyl, benzyl, 3-nitrobenzyl, 4-nitrobenzyl, 2-aminobenzyl, 3-aminobenzyl, pyrimidin-2-ylmethyl or a group derived by removing a hydrogen atom from a molecule selected from the group consisting of methylpropionate, 2-methylpyridine, ethylacetate, N,N-dimethylpropanamide, N-isopropylpropanamide, propamide, N,N-dimethylacetamide, N-methylacetamide, tert-butyl pyridin-2-yl-carbamate, N,N-dimethylbutanamide, methyl-1,3-thiazol-2-yl-acetamide, tert-butyl-1,3-thiazol-2-yl-carbamate, 3-methylpyridine, and tert-butyl -1-oxidopyridin-2-yl-carbamate; R 5 is -S 2 -, S or -S -; R 6 is 4-chloro-3-trifluoromethyl-phenyl, 3,4-dichlorophenyl, 3-methoxyphenyl, 4-methyl-3-nitrophenyl, 4-chlorophenyl, 4-chloro-3-methylphenyl, nitro-3-trifluoromethylphenyl, 2,4-difluorophenyl, 4-chloro-2-fluorophenyl, 3-chloro-2-fluorophenyl, 4-isopropylphenyl, 4-bromophenyl, 4-iodophenyl, 3-chlorophenyl, 1-benzofuran-2-yl, 5-methyl-2-furanyl, 2-furanyl or phenyl; R 7 is chlorine, cyano, methoxy or fluorine; R 17 is H; R 18 is H; and R 8 is H. R 1 is H; R 2 is methyl, isopropyl, 2-hydroxyethyl, hydroxycyclopentyl, ethyl, 2-aminoethyl, H-imidazol-2-ylmethyl, 1H-imidazol-4-ylmethyl, 2-[(aminocarbonyl)amino]ethyl, 6-aminopyridin-2-yl, 2-oxo-1,3-oxazolidin-5-yl-methyl, 2,6-dioxo-1,2,3,6-tetrahydropyrimidin-4-yl)methyl, 3-aminopropyl, 1H-pyrazol-3-ylmethyl, 2-amino-1,3-thiazol-4-yl)methyl, 2-nitrobenzyl, 3-methoxybenzyl, 5-nitro-1H-pyrazol-3-yl-methyl, 5-amino-1H-pyrazol-3-yl-methyl, 1-propyl-1H-imidazol-4-yl)methyl, 3-hydroxybenzyl, 5-amino-4H-1,2,4-triazol-3-yl)methyl, 2-pyridin-2-ylethyl, 2-(1H-pyrazol-4-yl)ethyl, 2-(3,5-dimethyl-1H-pyrazol-4-yl)ethyl, (2-fluoropyridin-3-yl)methyl, trifluoromethyl, benzyl, 3-nitrobenzyl, 4-nitrobenzyl, 2-aminobenzyl, 3-aminobenzyl, pyrimidin-2-ylmethyl or a group derived by removing a hydrogen atom from a molecule selected from the group consisting of methylpropionate, 2-methylpyridine, ethylacetate, N,N-dimethylpropanamide, N-isopropylpropanamide, propamide, N,N-dimethylacetamide, N-methylacetamide, tert-butyl pyridin-2-yl-carbamate, N,N-dimethylbutanamide, methyl-1,3-thiazol-2-yl-acetamide, tert-butyl-1,3-thiazol-2-yl-carbamate, 3-methylpyridine, and tert-butyl -1-oxidopyridin-2-yl-carbamate; R 5 is -S 2 -, S or -S -; R 6 is 4-chloro-3-trifluoromethyl-phenyl, 3,4-dichlorophenyl, 3-methoxyphenyl, 4-methyl-3-nitrophenyl, 4-chlorophenyl, 4-chloro-3-methylphenyl, nitro-3-trifluoromethylphenyl, 2,4-difluorophenyl, 4-chloro-2-fluorophenyl, 3-chloro-2-fluorophenyl, 4-isopropylphenyl, 4-bromophenyl, 4-iodophenyl, 3-chlorophenyl, 1-benzofuran-2-yl, 5-methyl-2-furanyl, 2-furanyl or phenyl; R 7 is chlorine, cyano, methoxy or fluorine; R 17 is H; R 18 is H; and R 8 is H.