4-(or 5-) substituted catechol derivatives

1. A compound of formula I:

or a salt thereof, wherein:

R 1 is chosen from H, (C 1 -C 8 )alkyl and halo(C 1 -C 8 )alkyl;

R 2 is chosen from H and halo;

Ar 1 is selected from optionally substituted phenyl and optionally substituted heteroaryl, wherein substituted phenyl and substituted heteroaryl refer to phenyl and heteroaryl residues wherein up to three H atoms in each residue are individually replaced with halogen, alkyl, haloalkyl, haloalkoxy, hydroxy, loweralkoxy, oxaalkyl, carboxy, carboalkoxy, carboxamido, alkylaminocarbonyl, alkoxycarbonyl, alkoxycarbonylamino, acyl, alkoxyalkyl, benzenesulfonyl, cyano, carbonyl, nitro, amino, urea, alkylurea, hydroxyalkyl, alkylamino, dialkylamino, aminoalkyl, (alkyl)(aryl)aminoalkyl, alkylaminoalkyl, dialkylaminoalkyl, dialkylaminoalkoxy, heterocyclylalkoxy, mercapto, alkylthio, alkylsulfinyl, alkylsulfonyl, acylamino, acylaminoalkyl, acylaminoalkoxy, amidino, acetoxy, sulfoxide, alkylsulfoxide, sulfone, alkylsulfone, sulfonylamino, alkylsulfonylamino, aryl, heterocyclyl, hydroxyimino, alkoxyimino, aminosulfonyl, trityl, amidino, guanidino, ureido, benzyloxyphenyl, benzyl, heteroaryl, heterocyclylalkyl, phenoxy, benzyloxy, heteroaryloxy, —NH(tBoc), or —NHSO 2 NH 2 ; and

Ar 2 is selected from:

(a) phenyl substituted in the para position with a single substituent selected from halogen, alkyl, haloalkyl, haloalkoxy, hydroxy, loweralkoxy, oxaalkyl, carboxy, carboalkoxy, carboxamido, alkylaminocarbonyl, alkoxycarbonyl, alkoxycarbonylamino, acyl, alkoxyalkyl, benzenesulfonyl, cyano, carbonyl, nitro, amino, urea, alkylurea, hydroxyalkyl, alkylamino, dialkylamino, aminoalkyl, (alkyl)(aryl)aminoalkyl, alkylaminoalkyl, dialkylaminoalkyl, dialkylaminoalkoxy, heterocyclylalkoxy, mercapto, alkylthio, alkylsulfinyl, alkylsulfonyl, acylamino, acylaminoalkyl, acylaminoalkoxy, amidino, acetoxy, sulfoxide, alkylsulfoxide, sulfone, alkylsulfone, sulfonylamino, alkylsulfonylamino, aryl, heterocyclyl, hydroxyimino, alkoxyimino, aminosulfonyl, trityl, amidino, guanidino, ureido, benzyloxyphenyl, benzyl, heteroaryl, heterocyclylalkyl, phenoxy, benzyloxy, heteroaryloxy, —NH(tBoc), and —NHSO 2 NH 2 ; and

(b) pyridinyl substituted in the para position with a single substituent selected from halogen, alkyl, haloalkyl, haloalkoxy, hydroxy, loweralkoxy, oxaalkyl, carboxy, carboalkoxy, carboxamido, alkylaminocarbonyl, alkoxycarbonyl, alkoxycarbonylamino, acyl, alkoxyalkyl, benzenesulfonyl, cyano, carbonyl, nitro, amino, urea, alkylurea, hydroxyalkyl, alkylamino, dialkylamino, aminoalkyl, (alkyl)(aryl)aminoalkyl, alkylaminoalkyl, dialkylaminoalkyl, dialkylaminoalkoxy, heterocyclylalkoxy, mercapto, alkylthio, alkylsulfinyl, alkylsulfonyl, acylamino, acylaminoalkyl, acylaminoalkoxy, amidino, acetoxy, sulfoxide, alkylsulfoxide, sulfone, alkylsulfone, sulfonylamino, alkylsulfonylamino, aryl, heterocyclyl, hydroxyimino, alkoxyimino, aminosulfonyl, trityl, amidino, guanidino, ureido, benzyloxyphenyl, benzyl, heteroaryl, heterocyclylalkyl, phenoxy, benzyloxy, heteroaryloxy, —NH(tBoc), and —NHSO 2 NH 2 .

2. A compound or salt according to claim 1 wherein Ar 2 is phenyl substituted in the para position with a group chosen from halogen, nitro, cyano, urea, alkylurea, hydroxy, alkylsulfonylamino, amino, haloalkyl, loweralkoxy, carboxy, alkoxycarbonyl, alkylaminocarbonyl, alkylamino, dialkylamino, mercapto, alkylthio, alkylsulfoxide, alkylsulfone, acylamino, phenyl and benzyl.

3. A compound or salt according to claim 2 wherein Ar 2 is phenyl substituted in the para position with a group chosen from halogen, urea, alkylurea, hydroxy, alkylsulfonylamino and amino.

4. A compound or salt according to claim 1 wherein Ar 2 is 3-pyridinyl substituted in the 6-position with a group chosen from halogen, nitro, cyano, urea, sulfonylurea, hydroxy, alkylsulfonylamino, amino, haloalkyl, loweralkoxy, carboxy, alkoxycarbonyl, alkylaminocarbonyl, alkylamino, dialkylamino, mercapto, alkylthio, alkylsulfoxide, alkylsulfone, acylamino, phenyl and benzyl.

5. A compound or salt according to claim 4 wherein Ar 2 is 3-pyridinyl substituted in the 6-position with a group chosen from urea, alkylsulfonylamino and amino.

6. A compound or salt according to claim 1 wherein R 2 is hydrogen.

7. A compound or salt according to claim 1 wherein R 2 is fluorine.

8. A compound of formula I:

or a salt thereof wherein:

R 1 is hydrogen;

R 2 is chosen from hydrogen and halo;

Ar 1 is selected from optionally substituted phenyl and optionally substituted heteroaryl; and

Ar 2 is selected from substituted phenyl and substituted heteroaryl,

wherein substituted phenyl and substituted heteroaryl refer to phenyl and heteroaryl residues wherein up to three H atoms in each residue are individually replaced with halogen, alkyl, haloalkyl, haloalkoxy, hydroxy, loweralkoxy, oxaalkyl, carboxy, carboalkoxy, carboxamido, alkylaminocarbonyl, alkoxycarbonyl, alkoxycarbonylamino, acyl, alkoxyalkyl, benzenesulfonyl, cyano, carbonyl, nitro, amino, urea, alkylurea, hydroxyalkyl, alkylamino, dialkylamino, aminoalkyl, (alkyl)(aryl)aminoalkyl, alkylaminoalkyl, dialkylaminoalkyl, dialkylaminoalkoxy, heterocyclylalkoxy, mercapto, alkylthio, alkylsulfinyl, alkylsulfonyl, acylamino, acylaminoalkyl, acylaminoalkoxy, amidino, acetoxy, sulfoxide, alkylsulfoxide, sulfone, alkylsulfone, sulfonylamino, alkylsulfonylamino, aryl, heterocyclyl, hydroxyimino, alkoxyimino, aminosulfonyl, trityl, amidino, guanidino, ureido, benzyloxyphenyl, benzyl, heteroaryl, heterocyclylalkyl, phenoxy, benzyloxy, heteroaryloxy, —NH(tBoc), or —NHSO 2 NH 2 ;

with the proviso that when R 1 and R 2 are both H, Ar 2 is not phenyl having substituents at the 2- and 6-positions.

9. A compound or salt according to claim 1 wherein R 1 is methyl.

10. A compound of formula I:

or a salt thereof wherein

(a) R 1 is hydrogen or methyl;

(b) R 2 is hydrogen or fluorine;

(c) Ar 1 is chosen from

(i) phenyl;

(ii) phenyl substituted in the meta or para position with a group chosen from halogen, nitro, cyano, trifluoromethyl and amino; and

(iii) pyridinyl; and

(d) Ar 2 is chosen from

(i) phenyl substituted in the para position with a substituent selected from halogen, alkyl, haloalkyl, haloalkoxy, hydroxy, loweralkoxy, oxaalkyl, carboxy, carboalkoxy, carboxamido, alkylaminocarbonyl, alkoxycarbonyl, alkoxycarbonylamino, acyl, alkoxyalkyl, benzenesulfonyl, cyano, carbonyl, nitro, amino, urea, alkylurea, hydroxyalkyl, alkylamino, dialkylamino, aminoalkyl, (alkyl)(aryl)aminoalkyl, alkylaminoalkyl, dialkylaminoalkyl, dialkylaminoalkoxy, heterocyclylalkoxy, mercapto, alkylthio, alkylsulfinyl, alkylsulfonyl, acylamino, acylaminoalkyl, acylaminoalkoxy, amidino, acetoxy, sulfoxide, alkylsulfoxide, sulfone, alkylsulfone, sulfonylamino, alkylsulfonylamino, aryl, heterocyclyl, hydroxyimino, alkoxyimino, aminosulfonyl, trityl, amidino, guanidino, ureido, benzyloxyphenyl, benzyl, heteroaryl, heterocyclylalkyl, phenoxy, benzyloxy, heteroaryloxy, —NH(tBoc), and —NHSO 2 NH 2 ; and

(ii) 3-pyridinyl substituted in the 6-position with a substituent selected from halogen, alkyl, haloalkyl, haloalkoxy, hydroxy, loweralkoxy, oxaalkyl, carboxy, carboalkoxy, carboxamido, alkylaminocarbonyl, alkoxycarbonyl, alkoxycarbonylamino, acyl, alkoxyalkyl, benzenesulfonyl, cyano, carbonyl, nitro, amino, urea, alkylurea, hydroxyalkyl, alkylamino, dialkylamino, aminoalkyl, (alkyl)(aryl)aminoalkyl, alkylaminoalkyl, dialkylaminoalkyl, dialkylaminoalkoxy, heterocyclylalkoxy, mercapto, alkylthio, alkylsulfinyl, alkylsulfonyl, acylamino, acylaminoalkyl, acylaminoalkoxy, amidino, acetoxy, sulfoxide, alkylsulfoxide, sulfone, alkylsulfone, sulfonylamino, alkylsulfonylamino, aryl, heterocyclyl, hydroxyimino, alkoxyimino, aminosulfonyl, trityl, amidino, guanidino, ureido, benzyloxyphenyl, benzyl, heteroaryl, heterocyclylalkyl, phenoxy, benzyloxy, heteroaryloxy, —NH(tBoc), and —NHSO 2 NH 2 .

11. A salt of a compound of claim 8 wherein the salt is a pharmaceutically acceptable salt.

12. A pharmaceutical composition comprising a pharmaceutically acceptable carrier and a compound or pharmaceutically acceptable salt according to claim 8 .

13. A pharmaceutical composition comprising

(a) a pharmaceutically acceptable carrier;

(b) a compound formula I:

or a pharmaceutically acceptable salt thereof, wherein

R 1 is chosen from H, (C 1 -C 8 )alkyl and halo(C 1 -C 8 )alkyl;

R 2 is chosen from H and halo;

Ar 1 is selected from optionally substituted phenyl and optionally substituted heteroaryl; and

Ar 2 is selected from substituted phenyl and substituted heteroaryl;

with the provisos that

(1) when R 1 and R 2 are both H, Ar 2 is not phenyl having substituents at the 2- and 6-positions; and

(2) when R 1 is CH 3 and R 2 is H, Ar e is not 2,4-diaminopyrimidin-5-yl,

wherein substituted phenyl and substituted heteroaryl refer to phenyl and heteroaryl residues wherein up to three H atoms in each residue are replaced with halogen, alkyl, haloalkyl, haloalkoxy, hydroxy, loweralkoxy, oxaalkyl, carboxy, carboalkoxy, carboxamido, alkylaminocarbonyl, alkoxycarbonyl, alkoxycarbonylamino, acyl, alkoxyalkyl, benzenesulfonyl, cyano, carbonyl, nitro, amino, urea, alkylurea, hydroxyalkyl, alkylamino, dialkylamino, aminoalkyl, (alkyl)(aryl)aminoalkyl, alkylaminoalkyl, dialkylaminoalkyl, dialkylaminoalkoxy, heterocyclylalkoxy, mercapto, alkylthio, alkylsulfinyl, alkylsulfonyl, acylamino, acylaminoalkyl, acylaminoalkoxy, amidino, acetoxy, sulfoxide, alkylsulfoxide, sulfone, alkylsulfone, sulfonylamino, alkylsulfonylamino, aryl, heterocyclyl, hydroxyimino, alkoxyimino, aminosulfonyl, trityl, amidino, guanidino, ureido, benzyloxyphenyl, benzyl, heteroaryl, heterocyclylalkyl, phenoxy, benzyloxy, heteroaryloxy, —NH(tBoc), or —NHSO 2 NH 2 ; and

(c) a second agent chosen from cholinesterase inhibitors, NMDA antagonists, calpain inhibitors and antioxidants.

14. A pharmaceutical composition according to claim 13 wherein said second agent is chosen from tacrine, huperzine, donepezil, lanicemine, remacemide, neramexane, memantine, vitamin E and coenzyme Q10.

15. A compound or salt according to claim 1 wherein Ar 1 is selected from:

(a) phenyl;

(b) phenyl substituted in the meta or para position with a single substituent; and

(c) pyridinyl.

16. A compound or salt according to claim 15 wherein Ar 1 is phenyl substituted in the meta or para position with a group chosen from halogen, nitro, cyano, fluoromethyl and amino.

17. A compound or salt according to claim 1 wherein

(a) R 1 is hydrogen or methyl;

(b) R 2 is hydrogen or fluorine;

(c) Ar 1 is chosen from

(i) phenyl;

(ii) phenyl substituted in the meta or para position with a group chosen from halogen, nitro, cyano, trifluoromethyl and amino; and

(iii) pyridinyl; and

(d) Ar e is chosen from

(i) phenyl substituted in the para position; and

(ii) 3-pyridinyl substituted in the 6-position.

18. A salt of a compound of claim 1 wherein the salt is a pharmaceutically acceptable salt.

19. A pharmaceutical composition comprising a pharmaceutically acceptable carrier and a compound or pharmaceutically acceptable salt according to claim 1 .

20. A salt of a compound of claim 8 wherein the salt is a pharmaceutically acceptable salt.

21. A pharmaceutical composition comprising a pharmaceutically acceptable carrier and a compound or pharmaceutically acceptable salt according to claim 10 .

22. A compound or salt according to claim 8 wherein Ar 2 is selected from substituted phenyl and substituted monocyclic heteroaryl.

23. A compound or salt according to claim 8 wherein Ar 1 is selected from:

(a) phenyl;

(b) phenyl substituted in the meta or para position with a single substituent; and

(c) pyridinyl.

24. A compound or salt according to claim 23 wherein Ar 1 is phenyl substituted in the meta or para position with a group chosen from halogen, nitro, cyano, fluoromethyl and amino.

25. A compound or salt according to claim 8 wherein R 2 is hydrogen.

26. A compound or salt according to claim 8 wherein R 2 is fluorine.

27. A pharmaceutical composition according to claim 13 wherein Ar 2 is selected from substituted phenyl and substituted monocyclic heteroaryl.

28. A pharmaceutical composition according to claim 13 wherein Ar 1 is selected from:

(a) phenyl;

(b) phenyl substituted in the meta or para position with a single substituent; and

(c) pyridinyl.

29. A pharmaceutical composition according to claim 13 wherein Ar 1 is phenyl substituted in the meta or para position with a group chosen from halogen, nitro, cyano, fluoromethyl and amino.