Bicyclic aza compounds as muscarinic M

1. A compound of the formula (1):

or a pharmaceutically acceptable 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 COR 5 , COOR 5 , CONR 5 R 6 , C(═NR 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 C(═NR 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 , CH 2 CH 2 NR 5 R 6 , an optionally substituted 5- or 6-membered ring containing 0, 1, 2, or 3 heteroatoms selected from O, N and S, and oxidized forms thereof, and a C 1-6 non-aromatic hydrocarbon group which is optionally substituted with one to six fluorine atoms, or which is 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, 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;

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 oxidized forms thereof; and

R 5 , R 6 and R 7 are each independently selected from hydrogen and 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 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.

2. The compound according to claim 1 , or a pharmaceutically acceptable salt thereof, wherein R 1 is selected from CH 2 CONR 5 R 6 , OCONR 5 R 6 , and a C 1-6 non-aromatic hydrocarbon group which is 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.

3. The compound according to claim 1 , or a pharmaceutically acceptable salt thereof, wherein R 1 is selected from CH 2 CONR 5 R 6 and OCONR 5 R 6 .

4. The compound according to claim 1 , or a pharmaceutically acceptable salt thereof, wherein R 5 is selected from C 1 -C 3 alkyl, or R 5 and R 6 are joined together to form a monocyclic or bicyclic ring containing 0, 1, 2, or 3 heteroatoms selected from O, N and S and oxidized forms thereof.

5. The compound according to claim 1 , or a pharmaceutically acceptable salt thereof, wherein R 6 is selected from C 1 -C 3 alkyl, or R 6 and R 5 are joined together to form a monocyclic or bicyclic ring containing 0, 1, 2, or 3 heteroatoms selected from O, N and S and oxidized forms thereof.

6. The compound according to claim 1 , or a pharmaceutically acceptable salt thereof, wherein R 5 and R 6 are joined together to form a 4 to 7 membered ring containing 0 or 1 oxygen atoms.

7. The compound according to claim 1 , or a pharmaceutically acceptable salt thereof, wherein R 1 is selected from:

8. The compound according to claim 1 , or a pharmaceutically acceptable salt thereof, wherein R 4 is selected from H, methyl, ethyl, ethynyl, and 1-propynyl.

9. The compound according to claim 1 , or a pharmaceutically acceptable salt thereof, wherein the bicyclic ring system formed by the moiety:

is selected from ring systems below:

10. The compound according to claim 1 , wherein the compound is selected from:

11. The compound according to claim 1 , wherein the compound is selected from:

ethyl-3-(3-(2-(diethylamino)-2-oxoethyl)azetidin-1-yl)-8-azabicyclo[3.2.1]octane-8-carboxylate;

ethyl-3-(3-(2-(ethyl(isopropyl)amino)-2-oxoethyl)azetidin-1-yl)-8-azabicyclo[3.2.1]octane-8-carboxylate;

ethyl-3-(3-(2-oxo-2-(1-azaspiro[3.3]heptan-1-yl)ethyl)azetidin-1-yl)-8-azabicyclo[3.2.1]octane-8-carboxylate;

ethyl-3-(3-(2-oxo-2-(piperidin-1-yl)ethyl)azetidin-1-yl)-8-azabicyclo[3.2.1]octane-8-carboxylate;

ethyl-5-(3-(2-(diethylamino)-2-oxoethyl)azetidin-1-yl)-2-azabicyclo[2.2.2]octane-2-carboxylate;

ethyl-5-(3-(2-(ethyl(isopropyl)amino)-2-oxoethyl)azetidin-1-yl)-2-azabicyclo[2.2.2]octane-2-carboxylate;

ethyl-5-(3-(2-oxo-2-(piperidin-1-yl)ethyl)azetidin-1-yl)-2-azabicyclo[2.2.2]octane-2-carboxylate;

ethyl-5-(3-(2-(1,4-oxazepan-4-yl)-2-oxoethyl)azetidin-1-yl)-2-azabicyclo[2.2.2]octane-2-carboxylate;

ethyl-5-(3-(2-oxo-2-(1-azaspiro[3.3]heptan-1-yl)ethyl)azetidin-1-yl)-2-azabicyclo[2.2.2]octane-2-carboxylate;

ethyl-3-(3-(2-(diethylamino)-2-oxoethyl)azetidin-1-yl)-9-azabicyclo[3.3.1]nonane-9-carboxylate;

ethyl-3-(3-(2-oxo-2-(pyrrolidin-1-yl)ethyl)azetidin-1-yl)-9-azabicyclo[3.3.1]nonane-9-carboxylate;

ethyl-3-(3-(2-oxo-2-(piperidin-1-yl)ethyl)azetidin-1-yl)-9-azabicyclo[3.3.1]nonane-9-carboxylate;

ethyl 6-(3-((diethylcarbamoyl)oxy)azetidin-1-yl)-2-azaspiro[3.3]heptane-2-carboxylate;

ethyl 2-(3-((diethylcarbamoyl)oxy)azetidin-1-yl)-6-azaspiro[3.4]octane-6-carboxylate;

1-(6-(ethoxycarbonyl)-6-azaspiro[3.4]octan-2-yl)azetidin-3-yl 1,4-oxazepane-4-carboxylate;

ethyl 6-(3-((ethyl(methyl)carbamoyl)oxy)azetidin-1-yl)-2-azaspiro[3.4]octane-2-carboxylate;

ethyl 6-(3-((diethylcarbamoyl)oxy)azetidin-1-yl)-2-azaspiro[3.4]octane-2-carboxylate;

methyl 6-(3-((diethylcarbamoyl)oxy)azetidin-1-yl)-2-azaspiro[3.4]octane-2-carboxylate;

ethyl 6-(3-((pyrrolidine-1-carbonyl)oxy)azetidin-1-yl)-2-azaspiro[3.4]octane-2-carboxylate;

1-(2-(ethoxycarbonyl)-2-azaspiro[3.4]octan-6-yl)azetidin-3-yl morpholine-4-carboxylate;

1-(2-(ethoxycarbonyl)-2-azaspiro[3.4]octan-6-yl)azetidin-3-yl 1,4-oxazepane-4-carboxylate;

ethyl 3-(3-((azepane-1-carbonyl)oxy)azetidin-1-yl)-8-azabicyclo[3.2.1]octane-8-carboxylate;

1-(8-(ethoxycarbonyl)-8-azabicyclo[3.2.1]octan-3-yl)azetidin-3-yl 1,4-oxazepane-4-carboxylate;

ethyl 5-(3-((diethylcarbamoyl)oxy)azetidin-1-yl)-2-azabicyclo[2.2.2]octane-2-carboxylate;

ethyl 5-(3-((pyrrolidine-1-carbonyl)oxy)azetidin-1-yl)-2-azabicyclo[2.2.2]octane-2-carboxylate;

ethyl 5-(3-((piperidine-1-carbonyl)oxy)azetidin-1-yl)-2-azabicyclo[2.2.2]octane-2-carboxylate;

ethyl 5-(3-((azepane-1-carbonyl)oxy)azetidin-1-yl)-2-azabicyclo[2.2.2]octane-2-carboxylate;

1-(2-(ethoxycarbonyl)-2-azabicyclo[2.2.2]octan-5-yl)azetidin-3-yl 1,4-oxazepane-4-carboxylate;

ethyl 3-(3-((diethylcarbamoyl)oxy)azetidin-1-yl)-9-azabicyclo[3.3.1]nonane-9-carboxylate; and

ethyl 7-(3-((azepane-1-carbonyl)oxy)azetidin-1-yl)-3-oxa-9-azabicyclo[3.3.1]nonane-9-carboxylate;

or a pharmaceutically acceptable salt thereof.

12. A pharmaceutical composition comprising a compound according to claim 1 , or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable excipient.

13. A method of lessening the severity of acute, chronic, neuropathic, or inflammatory pain in a subject, or treating a subject suffering from a disorder selected from Alzheimer's disease and dementia with Lewy bodies, comprising administering an effective amount of a compound according to claim 1 , or a pharmaceutically acceptable salt thereof, to the subject in need thereof.

14. The method according to claim 13 wherein the disorder is Alzheimer's disease.

15. The method according to claim 13 wherein the disorder is dementia with Lewy bodies.