Muscarinic M1 receptor agonists

1. A compound of the formula:

or a salt thereof, wherein:

n is 1 or 2;

R 1 is a C 1-10 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;

R 2 is hydrogen or a C 1-10 non-aromatic hydrocarbon group;

or R 1 and R 2 together with the nitrogen atom to which they are attached form a non-aromatic heterocyclic group of four to nine ring members, wherein the heterocyclic ring may optionally contain a second heteroatom selected from O, N and S and oxidised forms thereof; and wherein the heterocyclic ring may optionally be substituted with one to six more substitutents selected from C 1-2 alkyl; fluorine; and cyano;

R 3 is selected from hydrogen; halogen; cyano; hydroxy; C 1-3 alkoxy; and a C 1-5 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

R 4 is 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.

2. A compound according to claim 1 wherein n is 2.

3. A compound according to claim 1 wherein R 1 is selected from:

C 1-6 alkyl optionally substituted with 1 to 6 fluorine atoms;

methoxy-C 1-4 alkyl optionally substituted with 1 to 6 fluorine atoms;

C 1-6 alkoxy;

C 2-6 alkenyl;

C 2-6 alkynyl;

C 3-6 cycloalkyl optionally substituted with one or two methyl groups;

C 4-5 cycloalkyl-CH 2 — wherein the C 4-5 cycloalkyl moiety is optionally substituted with one C 1-2 alkyl group and wherein one carbon atom of the C 4-5 cycloalkyl moiety may optionally be replaced by an oxygen atom;

cyclopropyl-C 1-3 alkyl;

cyclopentenyl;

adamantyl; and

methyl-bicyclo[2.2.2]octanyl.

4. A compound according to claim 1 wherein R 1 is selected from 2-methylpropyl, tert-butyl, 2-methylbutyl, 2,2-dimethylpropyl, 2-methylbut-2-yl, cyclobutylmethyl, cyclopropylmethyl, cyclopentylmethyl, isopropyl, 1-methylcyclohexyl, 1-methylcyclopentylmethyl, 2-cyclopropylpropyl, 1-methylcyclobutyl, cyclopentyl, 2,3-dimethylbutan-2-yl, 1-ethylcyclobutylmethyl, 1-methylcyclopentyl, 2-cyclopropylpropan-2-yl, cyclobutyl, 1-methylcyclobutylmethyl, 1-(trifluoromethyl)cyclobutyl, 1-ethylcyclobutyl, ( 2 H 3 )methyl( 2 H 6 )propyl and 2-methylpentan-2-yl.

5. A compound according to claim 1 wherein R 2 is selected from hydrogen, methyl, ethyl and isopropyl.

6. A compound according to claim 1 wherein R 3 is selected from hydrogen, fluorine, cyano, methoxy and methyl.

7. A compound according to claim 1 wherein R 4 is selected from methyl, ethyl, ethynyl and 1-propynyl.

8. A compound according to claim 1 having the formula:

9. A compound according to claim 1 having the formula:

10. A compound according to claim 8 wherein R 3 is H.

11. A compound according to claim 8 wherein R 1 is selected from 2-methylpropyl, tert-butyl, 2-methylbutyl, 2,2-dimethylpropyl, 2-methylbut-2-yl, cyclobutylmethyl, cyclopropylmethyl, cyclopentylmethyl, isopropyl, 1-methylcyclohexyl, 1-methylcyclopentylmethyl, 2-cyclopropylpropyl, 1-methylcyclobutyl, cyclopentyl, 2,3-dimethylbutan-2-yl, 1-ethylcyclobutylmethyl, 1-methylcyclopentyl, 2-cyclopropylpropan-2-yl, cyclobutyl, 1-methylcyclobutylmethyl, 1-(trifluoromethyl)cyclobutyl, 1-ethylcyclobutyl, ( 2 H 3 )methyl( 2 H 6 )propyl and 2-methylpentan-2-yl.

12. A compound according to claim 1 wherein the compound is selected from the group consisting of

ethyl 4-(2-methylpropyl)carbamoyl)-1,4′-bipiperidine-1′-carboxylate;

ethyl 4-((3,3-difluoropyrrolidin-1-yl)carbamoyl)-1,4′-bipiperidine-1′-carboxylate;

ethyl 4-(2,3-dimethylbutan-2-yl)carbamoyl)-1,4′-bipiperidine-1′-carboxylate;

ethyl 4-(1,1-dimethylpropyl)carbamoyl)-1,4′-bipiperidine-1′-carboxylate;

ethyl 4-(1-methylcyclobutyl)carbamoyl)-1,4′-bipiperidine-1′-carboxylate;

ethyl 4-(4-((2-methylpropyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-((1,1-dimethylethyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-((2-methylbutyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-((2,2-dimethylpropyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-((1,1-dimethylpropyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-((cyclobutylmethyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-((diethyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-((ethyl(propan-2-yl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-((3-methoxy-2-methylpropyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-((cyclopropylmethyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-((cyclopentylmethyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-((1-methylcyclohexyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-(([1-methylcyclopentyl]methyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-((2,2,2-trifluoroethyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-((3,3,3-trifluoro-2-methoxypropyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-((tetrahydrofuran-3-ylmethyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-((methoxy(methyl))carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-((propan-2-yloxy))carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-((2-methylallyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-(butylcarbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-((cyclopropylmethyl)(ethyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-((1-methylcyclobutyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-((1-cyclopropylpropan-2-yl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-(cyclopent-3-en-1-ylcarbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-(cyclopentylcarbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-((2,3-dimethylbutan-2-yl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

4-(4-(allylcarbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-(2-methylpiperidine-1-carbonyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-(diisopropylcarbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-((2-methylbut-3-yn-2-yl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-(methyl(prop-2-yn-1-yl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-(((1-ethylcyclobutyl)methyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-((1,1,1-trifluoro-2-methylpropan-2-yl))carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-((2-cyclopropylpropyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-fluoro-4-((2-methylpropyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-fluoro-4-((1,1-dimethylpropyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-fluoro-4-((cyclobutylmethyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-fluoro-4-((tert-butyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-fluoro-4-((2,3-dimethylbutan-2-yl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-fluoro-4-((1-cyclopropylpropan-2-yl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-fluoro-4-((2,2-dimethylpropyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate

ethyl 4-(4-fluoro-4-((1-methylcyclopropyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate

ethyl 4-(4-fluoro-4-((1-methylcyclopentyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate

ethyl 4-(4-fluoro-4-(((1-ethylcyclobutyl)methyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate

ethyl 4-(4-fluoro-4-((1-methylcyclobutyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate

ethyl 4-(4-fluoro-4-((cyclopentyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-fluoro-4-((cyclopropylmethyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-fluoro-4-((cyclopentylmethyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-fluoro-4-((2-cyclopropylpropan-2-yl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-fluoro-4-((cyclobutyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-methyl-4-((2-methylpropyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

prop-2-yn-1-yl-4-(4-((2-methylpropyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

but-2-yn-1-yl-4-(4-((2-methylpropyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

2-fluoroethyl-4-(4-((2-methylpropyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

2-methoxyethyl-4-(4-((2-methylpropyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

2-propyl-4-(4-((2-methylpropyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

2,2,2-trifluoroethyl-4-(4-((2-methylpropyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl (4S)-4-[4-((2-methylpropyl)methylcarbamoyl)piperidin-1-yl]azepane-1-carboxylate;

ethyl (4R)-4-[4-((2-methylpropyl)methylcarbamoyl)piperidin-1-yl]azepane-1-carboxylate;

ethyl (4S)-4-{4-[(1-methylcyclobutyl)carbamoyl]piperidin-1-yl}azepane-1-carboxylate;

ethyl (4R)-4-{4-[(1-methylcyclobutyl)carbamoyl]piperidin-1-yl}azepane-1-carboxylate;

ethyl (4S)-4-[4-(tert-butylcarbamoyl)piperidin-1-yl]azepane-1-carboxylate;

ethyl (4R)-4-[4-(tert-butylcarbamoyl)piperidin-1-yl]azepane-1-carboxylate;

ethyl 4-(4-{[(1-methylcyclobutyl)methyl]carbamoyl}piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-(4-{[1-(trifluoromethyl)cyclobutyl]carbamoyl}piperidin-1-yl) azepane-1-carboxylate;

ethyl 4-{4-[(2-methylcyclopentyl)carbamoyl]piperidin-1-yl}azepane-1-carboxylate;

ethyl 4-{4-[(3-methylidenecyclobutyl)carbamoyl]piperidin-1-yl}azepane-1-carboxylate;

ethyl 4-{4-[(3-methylcyclobutyl)carbamoyl]piperidin-1-yl}azepane-1-carboxylate;

ethyl 4-{4-[(1-ethylcyclobutyl)carbamoyl]piperidin-1-yl}azepane-1-carboxylate;

ethyl 4-(4-{[2-(2H3)methyl(2H6)propyl]carbamoyl}piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-{4-[(1-fluoro-2-methylpropan-2-yl)carbamoyl]piperidin-1-yl}azepane-1-carboxylate;

ethyl 4-{4-[(2-methylpentan-2-yl)carbamoyl]piperidin-1-yl}azepane-1-carboxylate;

ethyl 4-{4-methyl-4-[(1-methylcyclobutyl)carbamoyl]piperidin-1-yl}azepane-1-carboxylate;

ethyl 4-{4-methoxy-4-[(1-methylcyclobutyl)carbamoyl]piperidin-1-yl}azepane-1-carboxylate;

but-2-yn-1-yl 4-{4-methoxy-4-[(1-methylcyclobutyl)carbamoyl]piperidin-1-yl}azepane-1-carboxylate;

ethyl 4-(4-methoxy-4-{[(1-methylcyclobutyl)methyl]carbamoyl}piperidin-1-yl)azepane-1-carboxylate;

ethyl 4-{4-cyano-4-[(1-methylcyclobutyl)carbamoyl]piperidin-1-yl}azepane-1-carboxylate;

and salts thereof.

13. A compound according to claim 1 which is selected from:

ethyl 4-(4-((2-methylpropyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl (4S)-4-[4-((2-methylpropyl)methylcarbamoyl)piperidin-1-yl]azepane-1-carboxylate;

ethyl (4R)-4-[4-((2-methylpropyl)methylcarbamoyl)piperidin-1-yl]azepane-1-carboxylate;

ethyl 4-(4-((1-methylcyclobutyl)carbamoyl)piperidin-1-yl)azepane-1-carboxylate;

ethyl (4S)-4-[4-[(1-methylcyclobutyl)carbamoyl]-1-piperidyl]azepane-1-carboxylate;

and salts thereof.

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