Heterocyclic Acetophenone Potentiators of Metabotropic Glutamate Receptors

A compound of the formula I:

• wherein:
• A is selected from the group consisting of phenyl, napthyl, azetidinyl, benzoxazolyl, benzofuranyl, benzimidazolyl, chromenyl, dihydroindenyl, dihydroisoquinolinyl, isoquinolinyl, imidazolyl, imidazopyridinyl, indanyl, indazolyl, indolyl, oxadiazolyl, purinyl, pyridyl, pyrimidinyl, quinolinyl, tetrahydroisoquinolinyl, and tetrazolyl, which is unsubstituted or substituted with oxo;
• X is selected from the group consisting of:
• (1) a bond;
• (2) —O—,
• (3) —S—,
• (4) —SO2—,
• (5) —NH—,
• (6) —N(C1-3alkyl)-,
• (7) —O-phenyl-,
• (8) —S-phenyl-,
• (9) —S—C1-3 alkyl-phenyl-,
• (10) -phenyl-, and
• (11) -piperazinyl-;
• Y is selected from the group consisting of:
• (1) —O—,
• (2) —NH(CO)—, and
• (3) a bond;
• R1 is selected from the group consisting of:
• (1) hydrogen,
• (2) C1-6alkyl, which is unsubstituted or substituted with a substituent selected from:
• (a) halogen,
• (b) hydroxyl, and
• (c) phenyl, wherein the phenyl is unsubstituted or substituted with 1-5 substituents independently selected from halogen, cyano, CF3, hydroxyl, C1-6alkyl, and OC1-6alkyl,
• (3) C3-7cycloalkyl, which is unsubstituted or substituted with halogen, hydroxyl or phenyl, and
• (4) phenyl, wherein the phenyl is unsubstituted or substituted with 1-5 substituents independently selected from halogen, hydroxyl, cyano, CF3, C1-6alkyl, and OC1-6alkyl, wherein the C1-6alkyl and OC1-6alkyl are linear or branched and optionally substituted with 1-5 halogen;
• R2 is selected from the group consisting of:
• (1) halogen,
• (2) hydroxyl,
• (3) —OC1-6alkyl, and
• (4) C1-6alkyl, which is unsubstituted or substituted with halogen, hydroxyl or phenyl;
• R3 is selected from the group consisting of:
• (1) halogen, and
• (2) C1-6alkyl, which is unsubstituted or substituted with halogen, hydroxyl or phenyl;
• R4 may include multiple substituents and is independently selected from the group consisting of:
• (1) hydrogen,
• (2) halogen,
• (3) C1-6alkyl, unsubstituted or substituted with halogen, —CN, —COC1-6alkyl or
• —CO2C1-6alkyl,
• (4) —O—C1-6alkyl,
• (5) phenyl,
• (6) pyridyl,
• (7) thiazolyl,
• (8) —CN, and
• (9) hydroxyl,
• or R4 may be joined to the phenyl ring at an adjacent carbon to form a dihydrofuranyl ring;
• m is an integer selected from 0, 1, 2 and 3;
• n is an integer selected from 0, 1, 2, 3, 4, 5 and 6;
• or a pharmaceutically acceptable salt thereof.

A compound which is selected from the group consisting of:

• 7-{4-[3-hydroxy-2-methyl-4-(3-methyl-butyryl)-phenoxy]-butoxy}-chromen-2-one;
• 1-[2-hydroxy-3-methyl-4-(4-phenoxy-butoxy)-phenyl]-3-methyl-butan-1-one;
• 1-[3-bromo-2-hydroxy-4-(4-phenoxy-butoxy)-phenyl]-3-methyl-butan-1-one;
• 1-{2-hydroxy-3-methyl-4-[4-(pyridin-3-yloxy)-butoxy]-phenyl}-3-methyl-butan-1-one;
• 1-{2-hydroxy-3-methyl-4-[4-(pyridin-2-yloxy)-butoxy]-phenyl}-3-methyl-butan-1-one;
• 1-{2-hydroxy-3-methyl-4-[4-(pyridin-4-yloxy)-butoxy]-phenyl}-3-methyl-butan-1-one;
• 1-{2-hydroxy-3-methyl-4-[3-(pyridin-3-yloxy)-propoxy]-phenyl}-3-methyl-butan-1-one;
• 1-{2-hydroxy-4-[4-(2-methoxy-phenoxy)-butoxy]-3-methyl-phenyl}-3-methyl-butan-1-one;
• 7-{4-[2-bromo-3-hydroxy-4-(3-methyl-butyryl)-phenoxy]-butoxy}-chromen-2-one;
• 1-{3-bromo-2-hydroxy-4-[4-(pyridin-3-yloxy)-butoxy]-phenyl}-3-methyl-butan-1-one;
• 1-{2-hydroxy-3-methyl 4-[5-(pyridin-3-yloxy)-pentyloxy]-phenyl}-3-methyl-butan-1-one;
• 1-{4-[4-(5-chloro-pyridin-3-yloxy)-butoxy]-2-hydroxy-3-methyl-phenyl}-3-methyl-butan-1-one;
• 1-{4-[4-(3-fluoro-phenoxy)-butoxy]-2-hydroxy-3-methyl-phenyl}-3-methyl-butan-1-one;
• 1-{2-hydroxy-3-methyl-4-[4-(3-trifluoromethyl-phenoxy)-butoxy]-phenyl}-3-methyl-butan-1-one;
• 1-{2-hydroxy-4-[4-(4-methoxy-phenoxy)-butoxy]-3-methyl-phenyl}-3-methyl-butan-1-one;
• 1-{4-[4-(3-chloro-phenoxy)-butoxy]-2-hydroxy-3-methyl-phenyl}-3-methyl-butan-1-one;
• 1-{2-hydroxy-3-methyl-4-[4-(pyrimidin-2-yloxy)-butoxy]-phenyl}-3-methyl-butan-1-one;
• 1-{4-[4-(2-fluoro-phenoxy)-butoxy]-2-hydroxy-3-methyl-phenyl}-3-methyl-butan-1-one;
• 1-{4-[4-(2,3-difluoro-phenoxy)-butoxy]-2-hydroxy-3-methyl-phenyl}-3-methyl-butan-1-one;
• 1-{2-hydroxy-4-[2-(isoquinolin-7-yloxy)-ethoxy]-3-methyl-phenyl}-3-methyl-butan-1-one;
• 1-{2-hydroxy-3-methyl-4-[4-(naphthalen-2-yloxy)-butoxy]-phenyl}-3-methyl-butan-1-one;
• 1-{4-[4-(2,3-dihydro-1H-inden-5-yloxy)butoxy]-2-hydroxy-3-methylphenyl}-3-methylbutan-1-one;
• 6-{4-[3-hydroxy-2-methyl-4-(3-methylbutanoyl)phenoxy]butoxy}indan-1-one;
• 1-(3-bromo-2-hydroxy-4-{[3-(pyridin-3-yloxy)benzyl]oxy}phenyl)-3-methylbutan-1-one;
• 1-{2-hydroxy-3-methyl-4-[4-(4-pyridin-4-ylpiperazin-1-yl)butoxy]phenyl}-3-methylbutan-1-one;
• 1-{2-hydroxy-3-methyl-4-[4-(4-pyridin-2-ylpiperazin-1-yl)butoxy]phenyl}-3-methylbutan-1-one;
• 1-{4-[4-(3,4-dihydroisoquinolin-2(1H)-yl)butoxy]-2-hydroxy-3-methylphenyl}-3-methylbutan-1-one;
• 7-(3-{[2-bromo-3-hydroxy-4-(3-methylbutanoyl)phenoxy]methyl}phenoxy)-2H-chromen-2-one;
• 1-{3-bromo-4-[4-(2,3-difluorophenoxy)butoxy]-2-hydroxyphenyl}-3-methylbutan-1-one;
• 1-[2-hydroxy-3-methyl-4-(4-{methyl[(6-methylpyridin-2-yl)methyl]amino}butoxy)phenyl]-3-methylbutan-1-one;
• 7-{4-[3-hydroxy-2-methyl-4-(3-methylbutanoyl)phenoxy]butoxy}-4-methyl-2H-chromen-2-one;
• 7-{4-[3-hydroxy-2-methyl-4-(3-methylbutanoyl)phenoxy]butoxy}-4-(trifluoromethyl)-2H-chromen-2-one;
• 1-{2-hydroxy-3-methyl-4-[4-(2-pyridin-2-yl-1H-benzimidazol-1-yl)butoxy]phenyl}-3-methylbutan-1-one;
• 1-{2-hydroxy-4-[4-(1H-imidazo[4,5-b]pyridin-1-yl)butoxy]-3-methylphenyl}-3-methylbutan-1-one;
• 1-(4-{4-[(2-chloropyridin-3-yl)oxy]butoxy}-2-hydroxy-3-methylphenyl)-3-methylbutan-1-one;
• 1-(2-hydroxy-3-methyl-4-{4-[(2-methylpyridin-3-yl)oxy]butoxy}phenyl)-3-methylbutan-1-one;
• 1-{4-[4-({2-[(dimethylamino)methyl]pyridin-3-yl}oxy)butoxy]-2-hydroxy-3-methylphenyl}-3-methylbutan-1-one;
• 6-{4-[3-hydroxy-2-methyl-4-(3-methylbutanoyl)phenoxy]butoxy}-4-methyl-2H-chromen-2-one;
• 7-{4-[3-hydroxy-2-methyl-4-(3-methylbutanoyl)phenoxy]butoxy}-3,4,8-trimethyl-2H-chromen-2-one;
• 1-(2-hydroxy-3-methyl-4-{4-[(6-methylpyridin-3-yl)oxy]butoxy}phenyl)-3-methylbutan-1-one;
• 1-(2-hydroxy-3-methyl-4-{4-[4-(1,3,4-oxadiazol-2-yl)phenoxy]butoxy}phenyl)-3-methylbutan-1-one;
• 2,3-difluoro-4-{4-[3-hydroxy-2-methyl-4-(3-methylbutanoyl)phenoxy]butoxy}benzonitrile;
• 1-{2-hydroxy-3-methyl-4-[4-(pentafluorophenoxy)butoxy]phenyl}-3-methylbutan-1-one;
• 1-{2-hydroxy-3-methyl-4-[4-(2,3,5,6-tetrafluorophenoxy)butoxy]phenyl}-3-methylbutan-1-one;
• 1-(2-hydroxy-3-methyl-4-{4-[(5-methylpyridin-3-yl)oxy]butoxy}phenyl)-3-methylbutan-1-one;
• 1-{2-hydroxy-3-methyl-4-[4-(2,3,4-trifluorophenoxy)butoxy]phenyl}-3-methylbutan-1-one;
• 1-{2-hydroxy-3-methyl-4-[4-(2,3,6-trifluorophenoxy)butoxy]phenyl}-3-methylbutan-1-one;
• 1-(2-hydroxy-4-{4-[(2-iodopyridin-3-yl)oxy]butoxy}-3-methylphenyl)-3-methylbutan-1-one;
• 1-{2-hydroxy-3-methyl-4-[4-(5,6,7,8-tetrahydroquinolin-3-yloxy)butoxy]phenyl}-3-methylbutan-1-one;
• 7-{3-[2-bromo-3-hydroxy-4-(3-methylbutanoyl)phenoxy]propoxy}-2H-chromen-2-one;
• 1-{3-bromo-2-hydroxy-4-[4-(2-pyridin-2-yl-1H-benzimidazol-1-yl)butoxy]phenyl}-3-methylbutan-1-one;
• 1-(4-{4-[(2,6-dimethylpyridin-3-yl)oxy]butoxy}-2-hydroxy-3-methylphenyl)-3-methylbutan-1-one;
• 1-{2-hydroxy-3-methyl-4-[4-(pyridin-4-ylthio)butoxy]phenyl}-3-methylbutan-1-one;
• 1-{2-hydroxy-3-methyl-4-[4-(4-pyrimidin-2-ylpiperazin-1-yl)butoxy]phenyl}-3-methylbutan-1-one;
• 1-{4-[4-(2,3-dichlorophenoxy)butoxy]-2-hydroxy-3-methylphenyl}-3-methylbutan-1-one;
• 1-{3-bromo-2-hydroxy-4-[4-(5,6,7,8-tetrahydroquinolin-3-yloxy)butoxy]phenyl}-3-methylbutan-1-one;
• 1-(2-hydroxy-3-methyl-{4-[(2,3,5,6-tetrafluorophenyl)thio]butoxy}phenyl)-3-methylbutan-1-one;
• 1-(4-{4-[(5-bromopyridin-3-yl)oxy]butoxy}-2-hydroxy-3-methylphenyl)-3-methylbutan-1-one;
• 1-{2-hydroxy-3-methyl-4-[4-(3-pyridin-2-ylphenoxy)butoxy]phenyl}-3-methylbutan-1-one;
• methyl-3-(2-hydroxy-4-{4-[3-hydroxy-2-methyl-4-(3-methylbutanoyl)phenoxy]butoxy}-phenyl)propanoate;
• 1-(2-hydroxy-3-methyl-4-{4-[2-(1,3-thiazol-4-yl)-1H-benzimidazol-1-yl]butoxy}phenyl)-3-methylbutan-1-one;
• 1-(4-{4-[(3-fluorophenyl)thio]butoxy}-2-hydroxy-3-methylphenyl)-3-methylbutan-1-one;
• 5-{3-[(4-Acetyl-3-hydroxy-2-propylphenoxy)methyl]phenoxy}pyridine-2-carbonitrile;
• 1-{2-hydroxy-3-methyl-4-[4-(4-pyridin-2-ylphenoxy)butoxy]phenyl}-3-methylbutan-1-one;
• 1-{4-[4-(1H-benzimidazol-1-yl)butoxy]-2-hydroxy-3-methylphenyl}-3-methylbutan-1-one;
• (1-{4-[3-hydroxy-2-methyl-4-(3-methylbutanoyl)phenoxy]butyl}-1H-benzimidazol-2-yl)acetonitrile;
• 1-(2-hydroxy-3-methyl-4-{4-[2-(trifluoromethyl)-1H-benzimidazol-1-yl]butoxy}phenyl)-3-methylbutan-1-one;
• 1-{3-[(4-acetyl-3-hydroxy-2-propylphenoxy)methyl]benzyl}azetidine-3-carbonitrile;
• 1-{4-[4-(1,3-benzothiazol-2-ylthio)butoxy]-2-hydroxy-3-methylphenyl}-3-methylbutan-1-one;
• 1-(4-{4-[(6-chloro-1,3-benzoxazol-2-yl)thio]butoxy}-2-hydroxy-3-methylphenyl)-3-methylbutan-1-one;
• 1-{2-hydroxy-3-methyl-4-[4-(2-phenyl-1H-imidazol-1-yl)butoxy]phenyl}-3-methylbutan-1-one;
• 1-{2-hydroxy-3-methyl-4-[4-(2-phenyl-1H-benzimidazol-1-yl)butoxy]phenyl}-3-methylbutan-1-one;
• 1-(2-hydroxy-3-methyl-4-{4-[(1-methyl-1H-tetrazol-5-yl)thio]butoxy}phenyl)-3-methylbutan-1-one;
• 1-{2-hydroxy-3-methyl-4-[4-(quinolin-3-yloxy)butoxy]phenyl}-3-methylbutan-1-one;
• 1-{4-[4-(1,3-benzoxazol-2-ylthio)butoxy]-2-hydroxy-3-methylphenyl}-3-methylbutan-1-one;
• 1-(4-{4-[(5-chloro-1,3-benzoxazol-2-yl)thio]butoxy}-2-hydroxy-3-methylphenyl)-3-methylbutan-1-one;
• 1-{2-hydroxy-4-[4-(1H-indol-1-yl)butoxy]-3-methylphenyl}-3-methylbutan-1-one;
• 1-{2-hydroxy-3-methyl-4-[4-(7H-purin-6-ylthio)butoxy]phenyl}-3-methylbutan-1-one;
• 1-{2-hydroxy-3-methyl-4-[4-(2-phenyl-1H-indol-1-yl)butoxy]phenyl}-3-methylbutan-1-one;
• 1-{2-hydroxy-3-methyl-4-[4-(pyridin-4-ylsulfonyl)butoxy]phenyl}-3-methylbutan-1-one;
• 1-{2-hydroxy-3-methyl-4-[4-(pyridin-3-ylthio)butoxy]phenyl}-3-methylbutan-1-one;
• 3′-[(4-Acetyl-3-hydroxy-2-propylphenoxy)methyl]biphenyl-2-carbonitrile;
• 1-hydroxy-3-{4-[3-hydroxy-2-methyl-4-(3-methylbutanoyl)phenoxy]butoxy}pyridinium;
• 1-{2-hydroxy-3-methyl-4-[4-(4-methyl-2-phenyl-1H-imidazol-1-yl)butoxy]phenyl}-3-methylbutan-1-one;
• 1-(2-hydroxy-3-methyl-4-{4-[2-(methylthio)-1H-benzimidazol-1-yl]butoxy}phenyl)-3-methylbutan-1-one;
• 1-(3-bromo-4-{4-[(6-chloro-1,3-benzoxazol-2-yl)thio]butoxy}-2-hydroxyphenyl)-3-methylbutan-1-one;
• 1-{2-hydroxy-3-methyl-4-[4-(4-phenyl-1H-imidazol-1-yl)butoxy]phenyl}-3-methylbutan-1-one;
• 1-{2-hydroxy-3-methyl-4-[4-(pyridin-2-ylthio)butoxy]phenyl}-3-methylbutan-1-one;
• 1-(4-{4-[2-(2-chlorophenyl)-1H-benzimidazol-1-yl]butoxy}-2-hydroxy-3-methylphenyl)-3-methylbutan-1-one;
• 1-(2-hydroxy-3-methyl-4-{4-[(1-oxidopyridin-2-yl)thio]butoxy}phenyl)-3-methylbutan-1-one;
• 1-(2-hydroxy-3-methyl-4-{[5-(2-phenyl-1H-benzimidazol-1-yl)pentyl]oxy}phenyl)-3-methylbutan-1-one;
• 7-{4-[3-hydroxy-2-methyl-4-(3-methylbutanoyl)phenoxy]butoxy}chroman-2-one;
• 1-(2-hydroxy-3-methyl-4-{4-[4-(3-oxobutyl)phenoxy]butoxy}phenyl)-3-methylbutan-1-one;
• 1-(2-hydroxy-3-methyl-4-{[3-(pyridin-4-ylthio)benzyl]oxy}phenyl)-3-methylbutan-1-one;
• 1-[4-(4-{[2-(2-fluorophenyl)-1H-benzimidazol-1-yl]oxy}butoxy)-2-hydroxy-3-methylphenyl]-3-methylbutan-1-one;
• 1-[4-(4-{[2-(4-fluorophenyl)-1H-benzimidazol-1-yl]oxy}butoxy)-2-hydroxy-3-methylphenyl]-3-methylbutan-1-one;
• 1-(4-{4-[2-(2,4-dichlorophenyl)-1H-imidazol-1-yl]butoxy}-2-hydroxy-3-methylphenyl)-3-methylbutan-1-one;
• 1-[4-(4-{[2-(3-chlorophenyl)-1H-benzimidazol-1-yl]oxy}butoxy)-2-hydroxy-3-methylphenyl]-3-methylbutan-1-one;
• 7-{4-[3-hydroxy-2-methyl-4-(3-methylbutanoyl)phenoxy]butoxy}-2,3-dihydro-4H-chromen-4-one;
• 1-(2-hydroxy-4-{4-[4-(3-hydroxypropyl)phenoxy]butoxy}-3-methylphenyl)-3-methylbutan-1-one;
• methyl 3-(4-{4-[3-hydroxy-2-methyl-4-(3-methylbutanoyl)phenoxy]butoxy}phenyl)-propanoate;
• 1-{2-hydroxy-4-[2-(6-hydroxy-1-benzofuran-3-yl)ethoxy]-3-methylphenyl}-3-methylbutan-1-one;
• methyl 2-hydroxy-4-{4-[3-hydroxy-2-methyl-4-(3-methylbutanoyl)phenoxy]butoxy}-benzoate;
• ethyl 7-{4-[3-hydroxy-2-methyl-4-(3-methylbutanoyl)phenoxy]butoxy}chromane-2-carboxylate;
• 1-{3-chloro-2,4-bis[4-(pyridin-4-ylthio)butoxy]phenyl}-3-methylbutan-1-one;
• 1-{3-bromo-2-hydroxy-4-[4-(pyridin-4-ylthio)butoxy]phenyl}-3-methylbutan-1-one;
• 1-{2-hydroxy-3-methyl-4-[4-(pyridin-4-ylthio)butoxy]phenyl}-3,3-dimethylbutan-1-one;
• 1-[2-hydroxy-3-methyl-4-({3-[(pyridin-4-ylthio)methyl]benzyl}oxy)phenyl]-3-methylbutan-1-one;
• 1-(2-hydroxy-3-methyl-4-{4-[(2-phenyl-1H-benzimidazol-1-yl)oxy]butoxy}phenyl)-3,3-dimethylbutan-1-one;
• 1-(2-hydroxy-3-methyl-4-{[4-(pyridin-4-ylthio)benzyl]oxy}phenyl)-3-methylbutan-1-one;
• 1-{2-hydroxy-4-[4-(3-hydroxyphenoxy)butoxy]-3-methylphenyl}-3-methylbutan-1-one;
• 1-{4-[4-(3,4-dihydro-2H-chromen-7-yloxy)butoxy]-2-hydroxy-3-methylphenyl}-3-methylbutan-1-one;
• 1-(2-hydroxy-3-methyl-4-{[4-(pyridin-4-ylthio)benzyl]oxy}phenyl)-3,3-dimethylbutan-1-one;
• 1-(3-bromo-2-hydroxy-4-{[4-(pyridin-4-ylthio)benzyl]oxy}phenyl)-3-methylbutan-1-one;
• 1-(2-hydroxy-3-methyl-4-{[3-(pyridin-4-ylthio)benzyl]oxy}phenyl)-3,3-dimethylbutan-1-one;
• 3′-{[4-(3,3-dimethylbutanoyl)-3-hydroxy-2-methylphenoxy]methyl}biphenyl-3-carboxamide;
• 1-(3-bromo-2-hydroxy-4-{4-[(2-phenyl-1H-benzimidazol-1-yl)oxy]butoxy}phenyl)-3-methylbutan-1-one;
• 1-[2-hydroxy-3-methyl-4-({4-[(pyridin-4-ylthio)methyl]benzyl}oxy)phenyl]-3-methylbutan-1-one;
• 1-[2-hydroxy-4-({3-methoxy-4-[(pyridin-4-ylthio)methyl]benzyl}oxy)-3-methylphenyl]-3-methylbutan-1-one;
• 1-(2-hydroxy-3-methyl-4-{[2-(pyridin-4-ylthio)benzyl]oxy}phenyl)-3-methylbutan-1-one;
• 1-(2-hydroxy-3-methyl-4-{4-[(2-methylpyridin-4-yl)thio]butoxy}phenyl)-3-methylbutan-1-one;
• 1-(2-hydroxy-3-methyl-4-{[3-(pyridin-3-ylamino)benzyl]oxy}phenyl)-3-methylbutan-1-one;
• 1-[2-hydroxy-3-methyl-4-({3-[(pyridin-4-ylthio)methyl]benzyl}oxy)phenyl]-3,3-dimethylbutan-1-one;
• 1-(2-hydroxy-3-methyl-4-{[3-(pyridin-2-ylamino)benzyl]oxy}phenyl)-3-methylbutan-1-one;
• 1-(2-hydroxy-3-methyl-4-{[3-(pyridin-4-ylamino)benzyl]oxy}phenyl)-3-methylbutan-1-one;
• 1-{2-hydroxy-4-[4-(1H-indazol-5-yloxy)butoxy]-3-methylphenyl}-3-methylbutan-1-one;
• 1-{2-hydroxy-4-[4-(1H-indazol-6-yloxy)butoxy]-3-methylphenyl}-3-methylbutan-1-one;
• 1-{2-hydroxy-4-[4-(1H-indol-4-yloxy)butoxy]-3-methylphenyl}-3-methylbutan-1-one;
• 1-{2-hydroxy-4-[4-(1H-indol-5-yloxy)butoxy]-3-methylphenyl}-3-methylbutan-1-one;
• 1-{2-hydroxy-4-[4-(1H-indol-6-yloxy)butoxy]-3-methylphenyl}-3-methylbutan-1-one;
• ethyl 5-[(3-{[3-hydroxy-2-methyl-4-(3-methylbutanoyl)phenoxy]methyl}phenyl)amino]-2-methoxybenzoate;
• 1-[2-hydroxy-4-({3-[(3-methoxyphenyl)amino]benzyl}oxy)-3-methylphenyl]-3-methylbutan-1-one;
• 1-[4-({3-[(3-ethoxyphenyl)amino]benzyl}oxy)-2-hydroxy-3-methylphenyl]-3-methylbutan-1-one;
• 1-[2-hydroxy-4-({3-[(3-isopropylphenyl)amino]benzyl}oxy)-3-methylphenyl]-3-methylbutan-1-one;
• 1-[2-hydroxy-3-methyl-4-({3-[methyl(pyridin-2-yl)amino]benzyl}oxy)phenyl]-3-methylbutan-1-one;
• 1-{2-(benzyloxy)-3-methyl-4-[4-(pyridin-4-ylthio)butoxy]phenyl}-3-methylbutan-1-one;
• or a pharmaceutically acceptable salt thereof.