Pharmaceutical compounds

1. A compound of the formula (1):

or a salt thereof, wherein:

X 1 and X 2 are saturated hydrocarbon groups which together contain a total of five to nine carbon atoms and zero or one oxygen atoms and which link together such that the moiety:

forms a monocyclic or bicyclic ring system optionally substituted with one or more fluorine atoms;

R 1 is selected from OR 5 ; NR 5 R 6 ; COR 5 ; COOR 5 ; CONR 5 R 6 ; CONR 5 OR 6 ; C(═NR 5 )R 6 ; C(═NOR 5 )R 6 ; OCOR 5 ; NR 7 COR 5 ; NR 7 CONR 5 R 6 ; NR 7 COOR 5 ; OCONR 5 R 6 ; CH 2 OR 5 ; CH 2 NR 5 R 6 ; CH 2 COR 5 ; CH 2 COOR 5 ; CH 2 CONR 5 R 6 ; CH 2 CONR 5 OR 6 ; CH 2 C(═NR 5 )R 6 ; CH 2 C(═NOR 5 )R 6 ; CH 2 OCOR 5 ; CH 2 NR 7 COR 5 ; CH 2 NR 7 CONR 5 R 6 ; CH 2 NR 7 COOR 5 ; CH 2 OCONR 5 R 6 ; a C 1-6 non-aromatic hydrocarbon group which is optionally substituted with one to six fluorine atoms and wherein one or two, but not all, carbon atoms of the hydrocarbon group may optionally be replaced by a heteroatom selected from O, N and S and oxidized forms thereof; and an optionally substituted 4, 5- or 6-membered ring containing 0, 1, 2 or 3 heteroatoms selected from O, N and S and oxidized forms thereof;

R 4 is H or a C 1-6 non-aromatic hydrocarbon group which is optionally substituted with one to six fluorine atoms and wherein one or two, but not all, carbon atoms of the hydrocarbon group may optionally be replaced by a heteroatom selected from O, N and S and oxidised forms thereof; and

R 5 , R 6 and R 7 are the same or different and each is independently selected from hydrogen, a non-aromatic C 1-6 hydrocarbon group optionally substituted with one or more fluorine atoms or optionally substituted with a 4, 5- or 6-membered ring containing 0, 1, 2 or 3 heteroatoms selected from O, N and S and oxidized forms thereof, or R 5 and R 6 can be joined together to form an optionally substituted monocyclic or bicyclic ring containing 0, 1, 2 or 3 heteroatoms selected from O, N and S and oxidized forms thereof.

2. The compound according to claim 1 wherein R 1 is selected from OR 5 ; NR 5 R 6 ; COOR 5 ; CONR 5 R 6 ; CONR 5 OR 6 ; C(═NOR 5 )R 6 ; CH 2 NR 7 COR 5 ; a C 1-3 alkyl group which is optionally substituted with one to three fluorine atoms; and an optionally substituted 4, 5- or 6-membered ring containing 1, or 2 heteroatoms selected from O, N and S and oxidized forms thereof.

3. The compound according to claim 1 wherein R 1 is selected from COOR 5 ; CONR 5 R 6 ; CONR 5 OR 6 ; C(═NOR 5 )R 6 ; and an optionally substituted 5-membered ring containing 1, or 2 hetero atoms selected from O, N and S and oxidized forms thereof.

4. The compound according to claim 1 wherein R 1 is selected from COOR 5 and CONR 5 R 6 .

5. The compound according to claim 1 wherein R 5 is selected from hydrogen, a non-aromatic C 1-6 hydrocarbon group optionally substituted with one or more fluorine atoms or optionally substituted with a 5- or 6-membered ring containing 0, 1, 2 or 3 heteroatoms selected from O, N and S and oxidized forms thereof, or R 5 and R 6 can be joined together to form an optionally substituted monocyclic or bicyclic ring containing 0, 1, 2 or 3 hetero atoms selected from O, N and S and oxidized forms thereof.

6. The compound according to claim 1 wherein R 6 is selected from hydrogen, a non-aromatic C 1-6 hydrocarbon group optionally substituted with one or more fluorine atoms or optionally substituted with a 4, 5- or 6-membered ring containing 0, 1, 2 or 3 heteroatoms selected from O, N and S and oxidized forms thereof, or R 5 and R 6 can be joined together to form an optionally substituted monocyclic or bicyclic ring containing 0, 1, 2 or 3 heteroatoms selected from O, N and S and oxidized forms thereof.

7. The compound according to claim 1 wherein R 1 is COOR 5 wherein R 5 is a non-aromatic C 1-6 hydrocarbon group or R 1 is CONR 5 R 6 wherein R 5 is a non-aromatic C 1-6 hydrocarbon group and R 6 is selected from hydrogen and a non-aromatic C 1-6 hydrocarbon group, or R 1 is CONR 5 R 6 and R 5 and R 6 are joined together to form an optionally substituted monocyclic or bicyclic ring containing, 0, 1, 2 or 3 heteroatoms selected from O, N and S and oxidized forms thereof, or R 1 is CONR 5 OR 6 wherein R 5 is a non-aromatic C 1-6 hydrocarbon group and R 6 is a non-aromatic C 1-6 hydrocarbon group.

8. The compound according to claim 1 wherein R 1 is selected from NR 5 R 6 ; CONR 5 R 6 ; and CH 2 NR 5 R 6 ; and R 5 and R 6 are joined together to form an optionally substituted monocyclic or bicyclic ring containing. 0, 1, 2 or 3 heteroatoms selected from O, N and S and oxidized forms thereof.

9. The compound according to claim 1 wherein R 1 is selected from the group consisting of:

10. The compound according to claim 1 wherein R 4 is selected from the group consisting of H, methyl, ethyl, ethynyl and 1-propynyl.

11. The compound according to claim 1 wherein the bicyclic ring system formed by the moiety:

is selected from ring systems below:

12. The compound according to claim 1 of the formula (2):

wherein n is 1 or 2.

13. The compound according to claim 1 wherein the compound is selected from the group consisting of:

ethyl 6-[(1R,5S,6r)-6-(ethoxycarbonyl)-3-azabicyclo[3.1.0]hex-3-yl]-2-azaspiro[3.3]heptane-2-carboxylate;

ethyl 6-[(1R,5S,6r)-6-(diethylcarbamoyl)-3-azabicyclo[3.1.0]hex-3-yl]-2-azaspiro[3.3]heptane-2-carboxylate;

ethyl 6-{(1R,5S,6r)-6-[ethyl(propan-2-yl)carbamoyl]-3-azabicyclo[3.1.0]hex-3-yl}-2-azaspiro[3.3]heptane-2-carboxylate;

ethyl 6-[(1R,5S,6r)-6-(2-methyl-1,3-thiazol-4-yl)-3-azabicyclo[3.1.0]hex-3-yl]-2-azaspiro[3.3]heptane-2-carboxylate;

ethyl 2-[(1R,5S,6r)-6-(ethoxycarbonyl)-3-azabicyclo[3.1.0]hex-3-yl]-6-azaspiro[3.4]octane-6-carboxylate;

ethyl 2-{(1R,5S,6r)-6-[(2-methylpropyl)carbamoyl]-3-azabicyclo[3.1.0]hex-3-yl}-6-azaspiro[3.4]octane-6-carboxylate;

ethyl 2-{(1R,5S,6r)-6-[(cyclobutylmethyl)carbamoyl]-3-azabicyclo[3.1.0]hex-3-yl}-6-azaspiro[3.4]octane-6-carboxylate;

ethyl 2-{(1R,5S,6r)-6-[(1-methylcyclobutyl)carbamoyl]-3-azabicyclo[3.1.0]hex-3-yl}-6-azaspiro[3.4]octane-6-carboxylate;

ethyl 2-{(1R,5S,6r)-6-[ethyl(methyl)carbamoyl]-3-azabicyclo[3.1.0]hex-3-yl}-6-azaspiro[3.4]octane-6-carboxylate;

ethyl 2-[(1R,5S,6r)-6-(diethylcarbamoyl)-3-azabicyclo[3.1.0]hex-3-yl]-6-azaspiro[3.4]octane-6-carboxylate;

methyl 2-[(1R,5S,6r)-6-(diethylcarbamoyl)-3-azabicyclo[3.1.0]hex-3-yl]-6-azaspiro[3.4]octane-6-carboxylate;

ethyl 2-{(1R,5S,6r)-6-[methyl(propan-2-yl)carbamoyl]-3-azabicyclo[3.1.0]hex-3-yl}-6-azaspiro[3.4]octane-6-carboxylate;

ethyl 2-{(1R,5S,6r)-6-[ethyl(propan-2-yl)carbamoyl]-3-azabicyclo[3.1.0]hex-3-yl}-6-azaspiro[3.4]octane-6-carboxylate;

methyl 2-{(1R,5S,6r)-6-[ethyl(propan-2-yl)carbamoyl]-3-azabicyclo[3.1.0]hex-3-yl}-6-azaspiro[3.4]octane-6-carboxylate;

ethyl 2-{(1R,5S,6r)-6-[cyclopropyl(ethyl)carbamoyl]-3-azabicyclo[3.1.0]hex-3-yl}-6-azaspiro[3.4]octane-6-carboxylate;

ethyl 2-[(1R,5S,6r)-6-(pyrrolidin-l-ylcarbonyl)-3-azabicyclo[3.1.0]hex-3-yl]-6-azaspiro[3.4]octane-6-carboxylate;

ethyl 2-[(1R,5S,6r)-6-(piperidin-1-ylcarbonyl)-3-azabicyclo[3.1.0]hex-3-yl]-6-azaspiro[3.4]octane-6-carboxylate;

ethyl 2-[(1R,5S,6r)-6-{[(2R)-2-methylpiperidin- 1-yl]carbonyl}-3-azabicyclo[3.1.0]hex-3-yl]-6-azaspiro[3.4]octane-6-carboxylate;

ethyl 2-[(1R,5S,6r)-6-{[(2S)-2-methylpiperidin-1-yl]carbonyl}-3-azabicyclo[3.1.0]hex-3-yl]-6-azaspiro[3.4]octane-6-carboxylate;

ethyl 2-[(1R,5S,6r)-6-(azepan-1-ylcarbonyl)-3-azabicyclo[3.1.0]hex-3-yl]-6-azaspiro[3.4]octane-6-carboxylate;

ethyl 2-[(1R,5S,6r)-6-(1,4-oxazepan-4-ylcarbonyl)-3-azabicyclo[3.1.0]hex-3-yl]-6-azaspiro[3.4]octane-6-carboxylate;

ethyl 2-[(1R,5S,6r)-6-(2-azaspiro[3.3]hept-2-ylcarbonyl)-3-azabicyclo[3.1.0]hex-3-yl]-6-azaspiro[3.4]octane-6-carboxylate;

ethyl 2-[(1R,5S,6r)-6-(4-azaspiro[2.3]hex-4-ylcarbonyl)-3-azabicyclo[3.1.0]hex-3-yl]-6-azaspiro[3.4]octane-6-carboxylate;

ethyl 2-[(1R,5S,6r)-6-(1-azaspiro[3.3]hept-1-ylcarbonyl)-3-azabicyclo[3.1.0]hex-3-yl]-6-azaspiro[3.4]octane-6-carboxylate;

methyl 2-[(1R,5S,6r)-6-(1-azaspiro[3.3]hept-1-ylcarbonyl)-3-azabicyclo[3.1.0]hex-3-yl]-6-azaspiro[3.4]octane-6-carboxylate;

ethyl 2-[(1R,5S,6r)-6-(6-oxa-1-azaspiro[3.3]hept-1-ylcarbonyl)-3-azabicyclo[3.1.0]hex-3-yl]-6-azaspiro[3.4]octane-6-carboxylate;

ethyl 2-{(1R,5S,6r)-6-[methoxy(methyl)carbamoyl]-3-azabicyclo[3.1.0]hex-3-yl}-6-azaspiro[3.4]octane-6-carboxylate;

ethyl 2-{(1R,5S,6r)-6-[ethyl(methoxy)carbamoyl]-3-azabicyclo[3.1.0]hex-3-yl}-6-azaspiro[3.4]octane-6-carboxylate;

ethyl 2-[(1R,5S,6r)-6-(N-methoxypropanimidoyl)-3-azabicyclo[3.1.0]hexan-3-yl]-6-azaspiro[3.4]octane-6-carboxylate;

ethyl 2-[6-(trifluoromethyl)-3-azabicyclo[3.1.0]hex-3-yl]-6-azaspiro[3.4]octane-6-carboxylate;

ethyl 2-{(1R,5S,6s)-6-[ethyl(2,2,2-trifluoroethyl)amino]-3-azabicyclo[3.1.0]hexan-3-yl}-6-azaspiro[3.4]octane-6-carboxylate;

ethyl 2-[(1R,5S,6s)-6-(1-phenylethoxy)-3-azabicyclo[3.1.0]hex-3-yl]-6-azaspiro[3.4]octane-6-carboxylate;

ethyl 2-[(1R,5S,6r)-6-(1-methyl-1H-pyrazol-5-yl)-3-azabicyclo[3.1.0]hex-3-yl]-6-azaspiro[3.4]octane-6-carboxylate;

ethyl 2-[(1R,5S,6r)-6-(2-methyl-1,3-thiazol-4-yl)-3-azabicyclo[3.1.0]hex-3-yl]-6-azaspiro[3.4]octane-6-carboxylate;

ethyl 6-[(1R,5S,6r)-6-(ethoxycarbonyl)-3-azabicyclo[3.1.0]hex-3-yl]-2-azaspiro[3.4]octane-2-carboxylate;

ethyl 6-[(1R,5S,6r)-6-(diethylcarbamoyl)-3-azabicyclo[3.1.0]hex-3-yl]-2-azaspiro[3.4]octane-2-carboxylate;

methyl 6-[(1R,5S,6r)-6-(diethylcarbamoyl)-3-azabicyclo[3.1.0]hex-3-yl]-2-azaspiro[3.4]octane-2-carboxylate;

ethyl 6-{(1R,5S,6r)-6-[ethyl(propan-2-yl)carbamoyl]-3-azabicyclo[3.1.0]hex-3-yl}-2-azaspiro[3.4]octane-2-carboxylate;

ethyl 4-[(1R,5S,6r)-6-(diethylcarbamoyl)-3-azabicyclo[3.1.0]hexan-3-yl]piperidine-1-carboxylate;

ethyl 6-[(1R,5S,6r)-6-(ethoxycarbonyl)-3-azabicyclo[3.1.0]hexan-3-yl]-3-azabicyclo[3.1.1]heptane-3-carboxylate;

ethyl 6-[(1R,5S,6r)-6-(diethylcarbamoyl)-3-azabicyclo[3.1.0]hexan-3-yl]-3-azabicyclo[3.1.1]heptane-3-carboxylate;

ethyl 8-[(1R,5S,6r)-6-(diethylcarbamoyl)-3-azabicyclo[3.1.0]hexan-3-yl]-3-azabicyclo[3.2.1]octane-3-carboxylate;

ethyl 3-[(1R,5S,6r)-6-(ethoxycarbonyl)-3-azabicyclo[3.1.0]hex-3-yl]-8-azabicyclo[3.2.1]octane-8-carboxylate;

ethyl 3-{(1R,5S,6r)-6-[ethyl(methyl)carbamoyl]-3-azabicyclo[3.1.0]hex-3-yl}-8-azabicyclo[3.2.1]octane-8-carboxylate;

ethyl 3-[(1R,5S,6r)-6-(diethylcarbamoyl)-3-azabicyclo[3.1.0]hex-3-yl]-8-azabicyclo[3.2.1]octane-8-carboxylate;

ethyl 3-{(1R,5S,6r)-6-[ethyl(propan-2-yl)carbamoyl]-3-azabicyclo[3.1.0]hex-3-yl}-8-azabicyclo[3.2.1]octane-8-carboxylate;

ethyl 3-[(1R,5S ,6r)-6-{[acetyl(ethyl)amino]methyl}-3-azabicyclo[3.1.0]hex-3-yl]-8-azabicyclo[3.2.1]octane-8-carboxylate;

ethyl 3-[(1R,5S,6r)-6-(2-methyl-1,3-thiazol-4-yl)-3-azabicyclo[3.1.0]hex-3-yl]-8-azabicyclo[3.2.1]octane-8-carboxylate;

ethyl 5-[(1R,5S,6r)-6-(ethoxycarbonyl)-3-azabicyclo[3.1.0]hex-3-yl]-2-azabicyclo[2.2.2]octane-2-carboxylate;

ethyl (1S,4S)-5-{(1R,5S,6r)-6-[ethyl(methyl)carbamoyl]-3-azabicyclo[3.1.0]hex-3-yl}-2-azabicyclo[2.2.2]octane-2-carboxylate;

ethyl (1R,4R)-5-{(1R,5S,6r)-6-[ethyl(methyl)carbamoyl]-3-azabicyclo[3.1.0]hexan-3-yl}-2-azabicyclo[2.2.2]octane-2-carboxylate;

ethyl (1S,4S)-5-[(1R,5S,6r)-6-(diethylcarbamoyl)-3-azabicyclo[3.1.0]hexan-3-yl]-2-azabicyclo[2.2.2]octane-2-carboxylate;

ethyl (1R,4R)-5-[(1R,5S,6r)-6-(diethylcarbamoyl)-3-azabicyclo[3.1.0]hexan-3-yl]-2-azabicyclo[2.2.2]octane-2-carboxylate;

methyl 5-[(1R,5S,6r)-6-(diethylcarbamoyl)-3-azabicyclo[3.1.0]hex-3-yl]-2-azabicyclo[2.2.2]octane-2-carboxylate;

ethyl 5-{(1R,5S,6r)-6-[ethyl(propan-2-yl)carbamoyl]-3-azabicyclo[3.1.0]hex-3-yl}-2-azabicyclo[2.2.2]octane-2-carboxylate;

ethyl (1S,4S)-5-{(1R,5S,6r)-6-[cyclopropyl(ethyl)carbamoyl]-3-azabicyclo[3.1.0]hex-3-yl}-2-azabicyclo[2.2.2]octane-2-carboxylate;

ethyl 5-{(1R,5S,6r)-6-[methoxy(methyl)carbamoyl]-3-azabicyclo[3.1.0]hexan-3-yl}-2-azabicyclo[2.2.2]octane-2-carboxylate;

ethyl 5-{(1R,5S,6r)-6-[ethyl(methoxy)carbamoyl]-3-azabicyclo[3.1.0]hex-3-yl}-2-azabicyclo[2.2.2]octane-2-carboxylate;

ethyl 3-{(1R,5S ,6r)-6-[ethyl(methyl)carbamoyl]-3 -azabicyclo[3.1.0]hex-3-yl}-9-azabicyclo[3.3.1]nonane-9-carboxylate;

ethyl 3-[(1R,5S,6r)-6-(diethylcarbamoyl)-3-azabicyclo[3.1.0]hex-3-yl]-9-azabicyclo[3.3.1]nonane-9-carboxylate;

methyl 3-[(1R,5S,6r)-6-(diethylcarbamoyl)-3-azabicyclo[3.1.0]hex-3-yl]-9-azabicyclo[3.3.1]nonane-9-carboxylate;

ethyl 7-{(1R,5S ,6r)-6-[ethyl(methyl)carbamoyl]-3-azabicyclo[3.1.0]hex-3-yl}-3-oxa-9-azabicyclo[3.3.1]nonane-9-carboxylate;

ethyl 7-[(1R,5S,6r)-6-(diethylcarbamoyl)-3-azabicyclo[3.1.0]hex-3-yl]-3-oxa-9-azabicyclo[3.3.1]nonane-9-carboxylate;

methyl 7-[(1R,5S,6r)-6-(diethylcarbamoyl)-3-azabicyclo[3.1.0]hex-3-yl]-3-oxa-9-azabicyclo[3.3.1]nonane-9-carboxylate;

ethyl 7-{(1R,5S,6r)-6-[methyl(propan-2-yl)carbamoyl]-3-azabicyclo[3.1.0]hexan-3-yl}-3-oxa-9-azabicyclo[3.3.1]nonane-9-carboxylate;

methyl 7-((1R,5S ,6r)-6-(isopropyl(methyl)carbamoyl)-3 -azabicyclo[3.1.0]hexan-3-yl)-3-oxa-9-azabicyclo[3.3.1]nonane-9-carboxylate;

ethyl 7-{(1R,5S ,6r)-6-[ethyl(propan-2-yl)carbamoyl]-3 -azabicyclo[3.1.0]hex-3-yl}-3-oxa-9-azabicyclo[3.3.1]nonane-9-carboxylate;

methyl 7-{(1R,5S,6r)-6-[ethyl(propan-2-yl)carbamoyl]-3-azabicyclo[3.1.0]hexan-3-yl}-3-oxa-9-azabicyclo[3.3.1]nonane-9-carboxylate;

ethyl 7-{(1R,5S,6r)-6-[cyclopropyl(methyl)carbamoyl]-3-azabicyclo[3.1.0]hexan-3-yl}-3-oxa-9-azabicyclo[3.3.1]nonane-9-carboxylate;

ethyl 7-{(1R,5S ,6r)-6-[cyclopropyl(ethyl)carbamoyl] -3-azabicyclo[3.1.0]hex-3-yl}-3-oxa-9-azabicyclo[3.3.1]nonane-9-carboxylate;

methyl 7-{(1R,5S,6r)-6-[cyclopropyl(ethyl)carbamoyl]-3-azabicyclo[3.1.0]hexan-3-yl}-3-oxa-9-azabicyclo[3.3.1]nonane-9-carboxylate;

ethyl 7-[(1R,5S,6r)-6-(piperidin-l-ylcarbonyl)-3-azabicyclo[3.1.0]hex-3-yl]-3-oxa-9-azabicyclo[3.3.1]nonane-9-carboxylate;

methyl 7-[(1R,5S,6r)-6-(piperidine-l-carbonyl)-3-azabicyclo[3.1.0]hexan-3-yl]-3-oxa-9-azabicyclo[3.3.1]nonane-9-carboxylate;

ethyl 7-[(1R,5S,6r)-6-(morpholine-4-carbonyl)-3-azabicyclo[3.1.0]hexan-3-yl]-3-oxa-9-azabicyclo[3.3.1]nonane-9-carboxylate;

ethyl 7-[(1R,5S,6r)-6-(azepan-1-ylcarbonyl)-3-azabicyclo[3.1.0]hex-3-yl]-3-oxa-9-azabicyclo[3.3.1]nonane-9-carboxylate;

ethyl 7-[(1R,5S,6r)-6-(1-azaspiro[3.3]hept-1-ylcarbonyl)-3-azabicyclo[3.1.0]hex-3-yl]-3-oxa-9-azabicyclo[3.3.1]nonane-9-carboxylate;

ethyl 4-[(1R,5S,6r)-6-(diethylcarbamoyl)-3-azabicyclo[3.1.0]hexan-3-yl]azepane-1-carboxylate;

ethyl 3-[(1R,5S,6r)-6-(diethylcarbamoyl)-3-azabicyclo[3.1.0]hexan-3-yl]-6-azabicyclo[3.2.1]octane-6-carboxylate; and

ethyl 5-[(1R,5S,6r)-6-(diethylcarbamoyl)-3-azabicyclo[3.1.0]hexan-3-yl]hexahydrocyclopenta[c]pyrrole-2(1H)-carboxylate, or salts thereof.

14. A pharmaceutical composition comprising a compound as defined in claim 1 and a pharmaceutically acceptable excipient.

15. The compound according to claim 13 which is methyl 6-[(1R,5S,6r)-6-(diethylcarbamoyl)-3-azabicyclo[3.1.0]hex-3-yl]-2-azaspiro[3.4]octane-2-carboxylate or a salt thereof.

16. The compound according to claim 13 which is ethyl 6-[(1R,5S,6r)-6-(diethylcarbamoyl)-3-azabicyclo[3.1.0]hex-3-yl]-2-azaspiro[3.4]octane-2-carboxylate or a salt thereof.

17. The compound according to claim 13 which is methyl 7-{(1R,5S,6r)-6-[ethyl(propan-2-yl)carbamoyl]-3-azabicyclo[3.1.0]hexan-3-yl}-3-oxa-9-azabicyclo[3.3.1]nonane-9-carboxylate or a salt thereof.