Inhibitors

1. A compound of formula (I):

or a pharmaceutically acceptable salt thereof, including all tautomers and stereoisomers thereof wherein:

R 1 represents hydrogen, halogen, —C 1-6 alkyl, C 2-6 alkenyl, C 2-6 alkynyl, -aryl, —C 1-6 alkylaryl, -cycloalkyl, —C 1-6 alkylcycloalkyl, -heteroaryl, —C 1-6 alkylheteroaryl, -heterocyclyl, —C 1-6 alkylheterocyclyl, -cycloalkyl substituted by phenyl, -cycloalkyl substituted by phenoxy, -phenyl substituted by cycloalkyl, -phenyl substituted by phenoxy, -phenyl substituted by phenyl, heterocyclyl substituted by phenyl, heteroaryl substituted by phenyl, phenyl substituted by heterocyclyl, phenyl substituted by heteroaryl, phenyl substituted by —O-cycloalkyl, phenyl substituted by -heterocyclyl-phenyl or phenyl substituted by -cycloalkyl-heterocyclyl;

and in which any of aforesaid aryl, cycloalkyl, heterocyclyl, heteroaryl, phenyl or phenoxy groups may optionally be substituted by one or more R b groups selected from C 1-6 alkyl, C 2-6 alkenyl, C 2-6 alkynyl, C 1-6 haloalkyl, —C 1-6 thioalkyl, —SOC 1-4 alkyl, —SO 2 C 1-4 alkyl, C 1-6 alkoxy-, C 1-6 haloalkoxy, —O—C 3-8 cycloalkyl, C 3-8 cycloalkyl, —SO 2 C 3-8 cycloalkyl, —SOC 3-6 cycloalkyl, C 3-6 alkenyloxy-, C 3-6 alkynyloxy-, —C(O)C 1-6 alkyl, —C(O)OC 1-6 alkyl, C 1-6 alkoxy-C 1-6 alkyl-, nitro, halogen, cyano, hydroxyl, ═O, —C(O)OH, —NH 2 , —NHC 1-4 alkyl, —N(C 1-4 -alkyl)(C 1-4 -alkyl), —C(O)N(C 1-4 -alkyl)(C 1-4 -alkyl), —C(O)NH 2 , —C(O)NH(C 1-4 -alkyl) and —C(O)NH(C 3-10 cycloalkyl);

R 2 represents ═O, —O—C 1-6 alkyl, —NR 3 R 4 or —O—C 1-6 haloalkyl, wherein if R 2 is ═O, the dashed line and solid line is a single bond and if R 2 is −O—C 1-6 alkyl, —NR 3 R 4 or —O—C 1-6 haloalkyl, the dashed and solid line is a double bond;

R 3 and R 4 independently represent hydrogen, C 1-6 alkyl or C 3-8 cycloalkyl; or R 3 and R 4 together with the nitrogen atom to which they are attached may form a heterocyclyl group optionally substituted by one or more R b groups;

n represents an integer selected from 0 to 3; and

R a represents C 1-6 alkyl, C 2-6 alkenyl, C 2-6 alkynyl, C 1-6 haloalkyl, —C 1-6 thioalkyl, —SOC 1-4 -alkyl, —SO 2 C 1-4 alkyl, C 1-6 alkoxy-, —O—C 3-8 cycloalkyl, C 3-8 cycloalkyl, —SO 2 C 3-8 cycloalkyl, —SOC 3-6 cycloalkyl, C 3-6 alkenyloxy-, C 3-6 alkynyloxy-, —C(O)C 1-6 alkyl, —C(O)OC 1-6 alkyl, C 1-6 alkoxy-C 1-6 alkyl-, nitro, halogen, cyano, hydroxyl, —C(O)OH, —NH 2 , —NHC 1-4 alkyl, —N(C 1-4 -alkyl)(C 1-4 -alkyl), —C(O)N(C 1-4 -alkyl)(C 1-4 -alkyl), —C(O)NH 2 , —C(O)NH(C 1-4 alkyl) and —C(O)NH(C 3-10 cycloalkyl).

2. A compound according to claim 1 , wherein R 1 represents —C 1-6 alkyl, -aryl, phenyl, substituted phenyl, -cycloalkyl, -heteroaryl, -heterocyclyl, substituted heterocyclyl, -cycloalkyl substituted by phenyl, -cycloalkyl substituted by phenoxy, -phenyl substituted by cycloalkyl, -phenyl substituted by phenoxy, -phenyl substituted by phenyl, heterocyclyl substituted by phenyl, heteroaryl substituted by phenyl, phenyl substituted by heterocyclyl, phenyl substituted by heteroaryl, phenyl substituted by —O-cycloalkyl, phenyl substituted by -heterocyclyl-phenyl or phenyl substituted by -cycloalkyl-heterocyclyl.

3. A compound according to claim 2 , wherein R 1 represents —C 1-6 alkyl, -aryl, -cycloalkyl, -heteroaryl, -cycloalkyl substituted by phenyl, -cycloalkyl substituted by phenoxy, -phenyl substituted by cycloalkyl, -phenyl substituted by phenyl, heterocyclyl substituted by phenyl, phenyl substituted by heterocyclyl, phenyl substituted by —O-cycloalkyl, phenyl substituted by -heterocyclyl-phenyl or phenyl substituted by -cycloalkyl-heterocyclyl.

4. A compound according to claim 2 , wherein R 1 represents —C 1-6 alkyl, -aryl, -cycloalkyl, -heteroaryl, -phenyl substituted by cycloalkyl, -phenyl substituted by phenyl, phenyl substituted by heterocyclyl, phenyl substituted by -heterocyclyl-phenyl or phenyl substituted by —O-cycloalkyl, wherein said phenyl group is optionally substituted by one or more halogen, C 1-6 alkoxy or C 1-6 haloalkoxy groups, wherein said heterocyclyl group is optionally substituted by one or more C 1-6 alkyl, halogen, C 3-8 cycloalkyl, hydroxyl or ═O groups, and wherein said cycloalkyl group is optionally substituted by one or more halogen or ═O groups.

5. A compound according to claim 2 , wherein R 1 represents -aryl , -phenyl substituted by cycloalkyl, phenyl substituted by heterocyclyl or phenyl substituted by -heterocyclyl-phenyl; wherein said phenyl group is optionally substituted by one or more halogen, C 1-6 alkoxy or C 1-6 haloalkoxy groups; wherein said heterocyclyl group is optionally substituted by one or more C 1-6 alkyl, halogen, C 3-8 cycloalkyl, hydroxyl or ═O groups; and wherein said cycloalkyl group is optionally substituted by one or more halogen or ═O groups.

6. A compound according to claim 2 , wherein R 1 represents -phenyl substituted by heterocyclyl, wherein said heterocyclyl group is optionally substituted by one or more ═O groups.

7. A compound according to claim 1 , wherein R 2 represents ═O, —O—C 1-6 alkyl or NR 3 R 4 , —NH-cyclohexyl or a heterocyclic group wherein said heterocyclic group is optionally substituted by one or more R b groups selected from halogen or C 1-6 alkyl.

8. A compound according to claim 1 , wherein R 2 represents ═O, —O—C 1-6 alkyl or NR 3 R 4 .

9. A compound according to claim 1 , wherein n represents 0.

10. A compound according to claim 1 , selected from the group consisting of:

or a pharmaceutically acceptable salt thereof, including all tautomers and stereoisomers.

11. A pharmaceutical composition comprising a compound according to claim 1 , optionally in combination with one or more therapeutically acceptable diluents or carriers.

12. The pharmaceutical composition of claim 11 , which comprises additionally at least one compound selected from the group consisting of neuroprotectants, antiparkinsonian drugs, amyloid protein deposition inhibitors, beta amyloid synthesis inhibitors, antidepressants, anxiolytic drugs, antipsychotic drugs and anti-multiple sclerosis drugs.

13. The pharmaceutical composition of claim 11 , which comprises additionally at least one compound, selected from the group consisting of PEP-inhibitors, LiCl, inhibitors of inhibitors of DP IV or DP IV-like enzymes, acetylcholinesterase (ACE) inhibitors, PIMT enhancers, inhibitors of beta secretases, inhibitors of gamma secretases, inhibitors of neutral endopeptidase, inhibitors of Phosphodiesterase-4 (PDE-4), TNFalpha inhibitors, muscarinic M1 receptor antagonists, NMDA receptor antagonists, sigma-1 receptor inhibitors, histamine H3 antagonists, immunomodulatory agents, immunosuppressive agents or an agent selected from the group consisting of antegren (natalizumab), Neurelan (fampridine-SR), campath (alemtuzumab), IR 208, NBI 5788/MSP 771 (tiplimotide), paclitaxel, Anergix.MS (AG 284), SH636, Differin (CD 271, adapalene), BAY 361677 (interleukin-4), matrix-metalloproteinase-inhibitors, interferon-tau (trophoblastin) and SAIK-MS.

14. A method of treatment of a disease selected from the group consisting of multiple sclerosis, mild cognitive impairment, Alzheimer's disease, Familial British Dementia, Familial Danish Dementia, neurodegeneration in Down Syndrome, Huntington's disease, rheumatoid arthritis, atherosclerosis, pancreatitis, and restenosis, which comprises administering to a subject an effective amount of a compound according to claim 1 , or a pharmaceutical composition comprising said compound and one or more therapeutically acceptable diluents or carriers.

15. A process for preparation of a compound of formula (I) according to claim 1 , which comprises:

(a) preparing a compound of formula (I) where R 2 represents ═O from a compound of formula (II)

wherein R a , n and R 1 are as defined in claim 1 and Alk represents an ethyl or butyl group, thereafter followed by a deprotection reaction; or

(b) interconversion of compounds of formula (I); and/or

(c) deprotecting a compound of formula (I) which is protected.

16. A compound according to claim 4 , wherein R 1 represents phenyl; -phenyl-cyclohexyl; -phenyl-pyrrolidinyl, -phenyl-morpholinyl, -phenyl-thiomorpholinyl, -phenyl-piperidinyl, -phenyl-piperazinyl, -phenyl-tetrahydrothiopyranyl or -phenyl-tetrahydropyranyl; or -phenyl-piperazinyl-phenyl;

wherein said phenyl group is optionally substituted by one or more fluorine, bromine or chlorine, butoxy, or difluorobutoxy groups; wherein said -phenyl-pyrrolidinyl, -phenyl-morpholinyl, -phenyl-thiomorpholinyl, -phenyl-piperidinyl, -phenyl-piperazinyl, -phenyl-tetrahydrothiopyranyl, -phenyl-tetrahydropyranyl, or phenyl-piperazinyl-phenyl is optionally substituted by one or more methyl, fluorine, cyclopropyl, hydroxyl, or ═O groups; and wherein said -phenyl-cyclohexyl is optionally substituted by one or more fluorine or ═O groups.

17. A compound according to claim 4 , wherein R 1 represents -phenyl substituted by -phenyl-morpholinyl or -phenyl-thiomorpholinyl, wherein said -morpholinyl or -thiomorpholinyl groups are optionally substituted by one or more ═O groups.

18. A compound according to claim 1 , wherein R 2 represents methoxy, —NHMe, —N(Me) 2 , —NH-cyclohexyl, piperidinyl, piperazinyl or morpholinyl wherein said heterocyclic group is optionally substituted by one or more R b groups such as fluorine or methyl.

19. A compound according to claim 1 , wherein R 2 represents ═O, methoxy, or piperidinyl.