Spiropiperidine allosteric modulators of nicotinic acetylcholine receptors

1. A compound having the formula I:

or a pharmaceutically acceptable salt thereof, wherein:

n is 0, 1 or 2;

X is S(O) 2 ;

R 1 is NR a R b ;

R a is H;

R b is H;

A is a 5-membered heteroaryl ring which is substituted with 1 to 3 R groups each independently selected from OH, NR 6 R 7 , CN, alkoxy, halogen, aminoalkyl, hydroxyalkyl, alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, and heterocyclyl, wherein said R groups selected from alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, and heterocyclyl, are optionally substituted with one or more substituents independently selected from R 11 ;

R 2 is independently halogen, (C 1 -C 4 )alkyl, or O(C 1 -C 4 )alkyl, wherein said alkyl is optionally substituted with one or more halogen;

or, two R 2 when both are (C 1 -C 4 )alkyl and are attached to the same carbon atom, come together to form a cyclopropyl, cyclobutyl, or cyclopentyl ring or, two R 2 when both are (C 1 -C 4 )alkyl and are not attached to the same carbon atom, come together and form a bridged ring, wherein said cyclopropyl, cyclobutyl, cyclopentyl or bridged ring may be optionally substituted with one or more substituents independently selected from OH, halogen, or (C 1 -C 4 )alkyl;

R 3 is H, halogen or (C 1 -C 4 )alkyl, wherein said alkyl is optionally substituted with one or more halogen;

R 4 is H, halogen or (C 1 -C 4 )alkyl, wherein said alkyl is optionally substituted with one or more halogen;

or, R 3 and R 4 come together to form a cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl ring wherein said ring may be optionally substituted with one or more substituents independently selected from OH, halogen, or (C 1 -C 4 )alkyl;

R 5 is H or (C 1 -C 4 )alkyl;

R 6 is H or (C 1 -C 4 )alkyl;

R 7 is H or (C 1 -C 4 )alkyl;

R 11 is halogen, OH, oxo, CF 3 , OCF 3 , CN, (C 1 -C 6 )alkyl, O(C 1 -C 6 )alkyl, S(C 1 -C 4 )alkyl, C═O(C 1 -C 4 )alkyl, NR 12 R 13 , (C═O)NR 6 R 7 , (C═O)OR 6 , (C 2 -C 4 )alkenyl, (C 2 -C 4 )alkynyl, (C 3 -C 6 )cycloalkyl, O(C 3 -C 6 )cycloalkyl, C═O(C 3 -C 6 )cycloalkyl, aryl, O-aryl, heteroaryl, or heterocyclyl, wherein said alkyl, cycloalkyl, aryl, heteroaryl, and heterocyclyl are optionally substituted with one or more halogen, (C 1 -C 4 )alkyl, (C 3 -C 6 )cycloalkyl, CF 3 , OCF 3 , OCH 3 , CN, OH and oxo;

R 12 is (C 1 -C 4 )alkyl, heterocyclyl, cycloalkyl, heteroaryl, aryl, or (C═O)R 6 , each optionally substituted with one or more substituents independently selected from halogen, (C 1 -C 4 )alkyl, and OH; and

R 13 is (C 1 -C 4 )alkyl, heterocyclyl, cycloalkyl, heteroaryl, aryl, or (C═O)R 6 , each optionally substituted with one or more substituents independently selected from halogen, (C 1 -C 4 )alkyl, and OH.

2. The compound according to claim 1 , or a pharmaceutically acceptable salt thereof, wherein R 2 is independently methyl, ethyl or F.

3. The compound according to claim 2 , or a pharmaceutically acceptable salt thereof, wherein A is a 5-membered heteroaryl ring which is substituted with 1 R group independently selected from OH, oxo, NR 6 R 7 , CN, alkoxy, halogen, aminoalkyl, hydroxyalkyl, alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, and heterocyclyl, wherein said R group selected from alkyl, alkenyl, alkynyl, cycloalkyl, aryl, heteroaryl, and heterocyclyl, are further optionally substituted with one or more substituents independently selected from R 11 .

4. The compound according to claim 3 , or a pharmaceutically acceptable salt thereof, wherein R is alkyl, cycloalkyl, aryl, heteroaryl, or heterocyclyl, each optionally substituted with one or more substituents independently selected from R 11 .

5. The compound according to claim 4 , or a pharmaceutically acceptable salt thereof, wherein R is cyclohexyl, phenyl, pyrazolyl, pyridinyl or isoxazolyl, each optionally substituted with one or more substituents independently selected from R 11 .

6. The compound according to claim 5 , or a pharmaceutically acceptable salt thereof, wherein R 3 and R 4 are independently selected from H, F, and methyl.

7. The compound of claim 1 , or a pharmaceutically acceptable salt thereof, having the formula (II):

wherein;

m is 0, 1, 2 or 3;

Z is independently selected from F, Cl, Br, methyl, methoxy, ethyl, ethoxy, propyl, —CH 2 OH, —CH 2 CH 2 OH, —CF 3 , —CH 2 CF 3 , —OCF 3 , —OCHF 2 , —OCH 2 CF 3 , and cyclopropyl;

Ring A is oxadiazolyl, oxazolyl, isoxazolyl, thiadiazolyl, isothiazolyl, thiazolyl, pyrazolyl or imidazolyl;

Ring B is cyclohexyl, phenyl, pyrazolyl, pyridinyl or isoxazolyl;

R 3 is H, F or (C 1 -C 4 )alkyl, wherein said alkyl is optionally substituted with one or more halogen; and

R 4 is H, F or (C 1 -C 4 )alkyl, wherein said alkyl is optionally substituted with one or more halogen.

8. The compound of claim 7 , or a pharmaceutically acceptable salt thereof, having the formula (II) or a pharmaceutically acceptable salt thereof, wherein;

m is 0, 1 or 2;

Z is independently selected from F, Cl, Br, methyl, methoxy, ethyl, ethoxy, propyl, —CH 2 OH, —CH 2 CH 2 OH, —CF 3 , —CH 2 CF 3 , —OCF 3 , —OCHF 2 , —OCH 2 CF 3 , and cyclopropyl;

Ring A is oxadiazolyl, oxazolyl, isoxazolyl, or thiazolyl;

Ring B is phenyl, pyrazolyl, pyridinyl or isoxazolyl; and

R 3 and R 4 are both H, or R 3 and R 4 are both F.

9. The compound of claim 1 which is selected from the group consisting of

(1R)-1-{5-[2-Methyl-5-(trifluoromethyl)phenyl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(2,5-Dimethylphenyl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

4,4-Difluoro-1-{3-[3-(2,2,2-trifluoroethoxy)phenyl]-1,2,4-oxadiazol-5-yl}-6-azaspiro[2.5]octane-6-sulfonamide, diastereomer C;

1-{3-[3-(Difluoromethoxy)phenyl]-1,2,4-oxadiazol-5-yl}-4-fluoro-6-azaspiro[2.5]octane-6-sulfonamide, diastereomer E;

(1R)-1-{3-[4-Fluoro-2-(trifluoromethyl)phenyl]-1,2,4-oxadiazol-5-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

1-{3-[4-Fluoro-2-(trifluoromethyl)phenyl]-1,2,4-oxadiazol-5-yl}-4-methyl-6-azaspiro[2.5]octane-6-sulfonamide, diastereomer D;

(1R)-1-{2-[3-(Trifluoromethoxy)phenyl]-1,3-thiazol-4-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[4-Methyl-1-(2,2,2-trifluoroethyl)-1H-pyrazol-5-yl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-[5-(1,4-Dimethyl-1H-pyrazol-5-yl)-1,2,4-oxadiazol-3-yl]-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-{5-[2-(Difluoromethoxy)pyridin-4-yl]-1,2,4-oxadiazol-3-yl}-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-[3-(3-Cyclopropylisoxazol-4-yl)-1,2,4-oxadiazol-5-yl]-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-1,1-Difluoro-2-{3-[1-(2,2,2-trifluoroethyl)-1H-pyrazol-5-yl]-1,2,4-oxadiazol-5-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-{5-[2-(Difluoromethoxy)-5-methylpyridin-4-yl]-1,2,4-oxadiazol-3-yl}-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-1,1-Difluoro-2-{5-[1-methyl-4-(trifluoromethyl)-1H-pyrazol-5-yl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{1-[3-(Trifluoromethoxy)phenyl]-1H-pyrazol-4-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-[5-(1-Cyclopropyl-1H-pyrazol-5-yl)-1,4-oxadiazol-2-yl]-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2S)-2-[5-(1-Cyclopropyl-1H-pyrazol-5-yl)-1,4-thiadiazol-2-yl]-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-[5-(6,7-Dihydro-4H-pyrazolo[5,1-c][1,4]thiazin-3-yl)-1,2,4-oxadiazol-3-yl]-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-1,1-Difluoro-2-{5-[1-methyl-3-(trifluoromethyl)-1H-pyrazol-4-yl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-1,1-Difluoro-2-[5-(2-methyl-2,4,5,6-tetrahydrocyclopenta[c]pyrazol-3-yl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-1,1-Difluoro-2-[5-(1,3,4-trimethyl-1H-pyrazol-5-yl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[4-(3-Cyclopropylisoxazol-4-yl)-1,3-oxazol-2-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-1,1-Difluoro-2-{2-[4-fluoro-2-(trifluoromethyl)phenyl]-1,3-oxazol-4-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-[5-(1-Cyclopropyl-4-methyl-1H-pyrazol-3-yl)-1,2,4-oxadiazol-3-yl]-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(1-Ethyl-5-methyl-1H-pyrazol-3-yl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(3-Cyclopropyl-5-methylisoxazol-4-yl)-1,3-oxazol-2-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-{5-[1-Cyclopropyl-3-(trifluoromethyl)-1H-pyrazol-5-yl]-1,2,4-oxadiazol-3-yl}-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-[5-(2-Cyclopropyl-5-methylphenyl)-1,2,4-oxadiazol-3-yl]-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-[2-(3-Cyclopropylisoxazol-4-yl)-1,3-oxazol-4-yl]-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(2-Methylphenyl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-[5-(2,5-Dimethylphenyl)-1,2,4-oxadiazol-3-yl]-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-{2-[2-(Difluoromethoxy)pyridin-4-yl]-1,3-oxazol-4-yl}-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

1,1-Difluoro-2-{1-[4-fluoro-2-(trifluoromethyl)phenyl]-1H-pyrazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

1,1-Difluoro-2-{5-[4-fluoro-2-(trifluoromethyl)phenyl]-1,2,4-thiadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[3-(5-Chloro-2-methoxyphenyl)-1,2,4-oxadiazol-5-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-1,1-Difluoro-2-(3-phenyl-1,2,4-oxadiazol-5-yl)-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-1,1-Difluoro-2-{3-[4-fluoro-2-(trifluoromethyl)phenyl]-1,2,4-oxadiazol-5-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{3-[5-Fluoro-2-(trifluoromethyl)phenyl]-1,2,4-oxadiazol-5-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{3-[3-(Difluoromethoxy)phenyl]-1,2,4-oxadiazol-5-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-1,1-Difluoro-2-[3-(3-fluorophenyl)-1,2,4-oxadiazol-5-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-[3-(2,4-Difluorophenyl)-1,2,4-oxadiazol-5-yl]-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-1,1-Difluoro-2-{3-[4-(2-hydroxypropan-2-yl)phenyl]-1,2,4-oxadiazol-5-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

1-{3-[2-(Methylamino)pyridin-3-yl]-1,2,4-oxadiazol-5-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

1-{3-[2-(Pyrrolidin-1-yl)pyridin-4-yl]-1,2,4-oxadiazol-5-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

2-[3-(3,5-Dimethylisoxazol-4-yl)-1,2,4-oxadiazol-5-yl]-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[3-(3-Cyclopropylisoxazol-4-yl)-1,2,4-oxadiazol-5-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-[3-(3-Cyclopropyl-5-methylisoxazol-4-yl)-1,2,4-oxadiazol-5-yl]-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-(3-Cyclohexyl-1,2,4-oxadiazol-5-yl)-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-1,1-Difluoro-2-[3-(2-methylpyridin-3-yl)-1,2,4-oxadiazol-5-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-1,1-Difluoro-2-{3-[2-(trifluoromethyl)pyridin-4-yl]-1,2,4-oxadiazol-5-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-{3-[2-(Difluoromethoxy)pyridin-4-yl]-1,2,4-oxadiazol-5-yl}-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-[3-(1-Cyclopropyl-4-methyl-1H-pyrazol-5-yl)-1,2,4-oxadiazol-5-yl]-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-1,1-Difluoro-2-[3-(imidazo[1,2-a]pyridin-7-yl)-1,2,4-oxadiazol-5-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{3-[5-Cyclopropyl-3-(trifluoromethyl)isoxazol-4-yl]-1,2,4-oxadiazol-5-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

1-[3-(5-Chloro-2-methoxyphenyl)-1,2,4-oxadiazol-5-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-[3-(1-Cyclopropyl-1H-pyrazol-5-yl)-1,2,4-oxadiazol-5-yl]-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-{3-[3-Cyclopropyl-5-(trifluoromethyl)isoxazol-4-yl]-1,2,4-oxadiazol-5-yl}-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-{3-[5-Cyclopropyl-3-(trifluoromethyl)isoxazol-4-yl]-1,2,4-oxadiazol-5-yl}-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

1,1-Dichloro-2-{3-[4-fluoro-2-(trifluoromethyl)phenyl]-1,2,4-oxadiazol-5-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[3-(Trifluoromethyl)phenyl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(5-Chloro-2-methoxyphenyl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(2-Cyanophenyl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[2-(Difluoromethoxy)phenyl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[4-(Trifluoromethyl)phenyl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[5-Bromo-2-(trifluoromethyl)phenyl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[4-Chloro-2-(trifluoromethyl)phenyl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-(5-Phenyl-1,2,4-oxadiazol-3-yl)-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[2-(Difluoromethoxy)-4-(trifluoromethyl)phenyl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[4-Chloro-2-(difluoromethoxy)phenyl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[3-(Difluoromethoxy)phenyl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[2-Fluoro-6-(trifluoromethyl)phenyl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(4-Methoxyphenyl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[4-(Difluoromethoxy)phenyl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(2,4-Difluorophenyl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[4-Fluoro-2-(trifluoromethyl)phenyl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[2-(Trifluoromethyl)phenyl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[2-(2,2,2-Trifluoroethoxy)phenyl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(2,4-Dimethylphenyl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[2-(Trifluoromethoxy)phenyl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[5-Fluoro-2-(trifluoromethoxy)phenyl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[5-Chloro-2-(trifluoromethoxy)phenyl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[4-(2-Hydroxypropan-2-yl)phenyl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[2-(Difluoromethoxy)-4-fluorophenyl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(2,4,5-Trimethylphenyl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-[5-(2-Cyclopropylphenyl)-1,2,4-oxadiazol-3-yl]-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(5-Fluoro-2-methoxyphenyl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(1-Cyclopropyl-3-methyl-1H-indol-5-yl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(2-Methylpyridin-3-yl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[3-(Propan-2-yl)cyclobutyl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[2-Fluoro-6-(trifluoromethyl)benzyl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[2-Fluoro-5-(trifluoromethyl)benzyl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(2,6-Dimethylbenzyl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(3-Methylcyclohexyl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[1-(2-Chlorophenyl)ethyl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[5-Fluoro-2-(trifluoromethyl)benzyl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[1-(2,5-Difluorophenyl)cyclobutyl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(Spiro[2.5]oct-4-yl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[4-Fluoro-2-(trifluoromethyl)benzyl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(4-Fluoro-2,3-dihydro-1H-inden-1-yl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-(5-{1-[3-(Trifluoromethyl)phenyl]cyclopropyl}-1,2,4-oxadiazol-3-yl)-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(3-Phenylcyclobutyl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(3,6-Dimethylpyridin-2-yl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[6-(Trifluoromethyl)pyridin-2-yl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[2-(2,2,2-Trifluoroethoxy)pyridin-4-yl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[3-Methyl-6-(trifluoromethyl)pyridin-2-yl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(Spiro[3.3 ]hept-2-yl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(1-Ethyl-3-methyl-1H-pyrazol-5-yl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[1-(2,2,2-Trifluoroethyl)-1H-pyrazol-4-yl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[4-(Trifluoromethyl)-1,3-oxazol-5-yl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(4-Ethyl-1,3-oxazol-5-yl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[1-(2,2,2-Trifluoroethyl)-1H-pyrazol-3-yl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(3-Cyclopropylisoxazol-4-yl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(4,5-Dimethylisoxazol-3-yl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[(3,5-Dimethylisoxazol-4-yl)methyl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[3-(Trifluoromethyl)isoxazol-4-yl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(1-Cyclopropyl-1H-pyrazol-5-yl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[2-(1H-Imidazol-1-yl)-5-(trifluoromethyl)pyridin-4-yl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[1-Methyl-4-(trifluoromethyl)-1H-pyrazol-5-yl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-{5-[2-(Cyclopropyloxy)pyridin-4-yl]-1,2,4-oxadiazol-3-yl}-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-[5-(1-Cyclopropyl-1H-pyrazol-5-yl)-1,2,4-oxadiazol-3-yl]-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-[5-(1-tert-Butyl-1H-pyrazol-5-yl)-1,2,4-oxadiazol-3-yl]-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-1,1-Difluoro-2-[5-(3-methylimidazo[1,2-a]pyridin-7-yl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-[5-(3-Cyclopropyl-1-ethyl-1H-pyrazol-4-yl)-1,2,4-oxadiazol-3-yl]-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-1,1-Difluoro-2-{5-[1-methyl-5-(trifluoromethyl)-1H-pyrazol-4-yl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-{5-[1-tert-Butyl-5-(trifluoromethyl)-1H-pyrazol-4-yl]-1,2,4-oxadiazol-3-yl}-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-1,1-Difluoro-2-[5-(4,5,6,7-tetrahydropyrazolo[1,5-a]pyridin-3-yl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-[5-(1-Cyclopropyl-4-methyl-1H-pyrazol-5-yl)-1,2,4-oxadiazol-3-yl]-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-[5-(5,6-Dihydro-4H-pyrrolo[1,2-b]pyrazol-3-yl)-1,2,4-oxadiazol-3-yl]-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-1,1-Difluoro-2-[5-(1-methyl-1H-pyrazol-5-yl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-1,1-Difluoro-2-[5-(1-methyl-1,4,5,6-tetrahydrocyclopenta[c]pyrazol-3-yl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-1,1-Difluoro-2-{5-[1-methyl-3-(trifluoromethyl)-1H-pyrazol-5-yl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-{5-[1-Cyclopropyl-5-(trifluoromethyl)-1H-pyrazol-3-yl]-1,2,4-oxadiazol-3-yl}-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-[5-(2-Cyclopropyl-4,5,6,7-tetrahydro-2H-indazol-3-yl)-1,2,4-oxadiazol-3-yl]-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-{5-[1-Cyclopropyl-4-(trifluoromethyl)-1H-pyrazol-5-yl]-1,2,4-oxadiazol-3-yl}-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-[5-(3-Cyclopropylpyridazin-4-yl)-1,2,4-oxadiazol-3-yl]-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(3-Cyclopropylpyridazin-4-yl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-1,1-Difluoro-2-{5-[2-(propan-2-yloxy)pyridin-4-yl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(1,4-Dimethyl-1H-pyrazol-5-yl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-1,1-Difluoro-2-[5-(4H-pyrazolo[1,5-c][1,3 ]thiazol-3-yl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-{5-[1-Cyclopropyl-5-methyl-3-(trifluoromethyl)-1H-pyrazol-4-yl]-1,2,4-oxadiazol-3-yl}-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-{5-[3-Cyclopropyl-5-(trifluoromethyl)isoxazol-4-yl]-1,2,4-oxadiazol-3-yl}-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-1,1-Difluoro-2-[5-(pyridin-3-yl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[4-(Trifluoromethyl)pyridin-3-yl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[2-(Trifluoromethyl)pyridin-3-yl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[2-(2,2,2-Trifluoroethoxy)pyridin-3-yl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[5-(2,2,2-Trifluoroethoxy)pyridin-3-yl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[2-Methyl-5-(trifluoromethyl)pyridin-3-yl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[1-(Propan-2-yl)-1H-pyrazol-5-yl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[6-(2,2,2-Trifluoroethoxy)pyridin-3-yl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(1-Cyclopropyl-4-methyl-1H-pyrazol-5-yl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(2-Methyl-4,5,6,7-tetrahydro-2H-indazol-3-yl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-1,1-Difluoro-2-[5-(2-methyl-4,5,6,7-tetrahydro-2H-indazol-3-yl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-1,1-Difluoro-2-[5-(pyridin-2-yl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-1,1-Difluoro-2-{5-[3-(trifluoromethyl)isoxazol-4-yl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(2,3-Dihydro-1H-inden-4-yl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-(5-{3-[5-(Trifluoromethyl)-1H-pyrazol-1-yl]phenyl}-1,2,4-oxadiazol-3-yl)-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(2-Phenoxyphenyl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(5,6,7,8-Tetrahydronaphthalen-2-yl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[2-(1H-Pyrrol-1-yl)phenyl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(4′-Fluorobiphenyl-3-yl)-1,2,4-oxadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[2-(1-Cyanocyclopropyl)phenyl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[2-(Pyrimidin-2-yl)phenyl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[2-(1H-Pyrazol-1-yl)phenyl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[3-(2,2,2-Trifluoroethoxy)pyridin-2-yl]-1,2,4-oxadiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[4-Fluoro-2-(trifluoromethyl)phenyl]-1,3,4-oxadiazol-2-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[3-(Trifluoromethyl)phenyl]-1,3,4-oxadiazol-2-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[3-(Trifluoromethoxy)phenyl]-1,3,4-oxadiazol-2-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(2,5-Difluorophenyl)-1,3,4-thiadiazol-2-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(5-Fluoro-2-methylphenyl)-1,3,4-oxadiazol-2-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[2-(2,2,2-Trifluoroethoxy)phenyl]-1,3,4-oxadiazol-2-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[2-(2,2,2-Trifluoroethoxy)phenyl]-1,3,4-thiadiazol-2-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(2-Methylphenyl)-1,3,4-thiadiazol-2-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[4-Fluoro-2-(trifluoromethyl)phenyl]-1,3,4-thiadiazol-2-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-{5-[3-(Difluoromethoxy)phenyl]-1,3,4-thiadiazol-2-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(3-Cyclopropyl-5-methylisoxazol-4-yl)-1,3,4-oxadiazol-2-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[5-(3-Cyclopropyl-5-methylisoxazol-4-yl)-1,3,4-thiadiazol-2-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-1,1-Difluoro-2-[5-(2-methylphenyl)-1,3,4-oxadiazol-2-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-1,1-Difluoro-2-[5-(2-methylphenyl)-1,3,4-thiadiazol-2-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-(4-Phenyl-1,3-oxazol-2-yl)-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[2-(3-Cyclopropylisoxazol-4-yl)-1,3-thiazol-4-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(1R)-1-[1-(3,5-Dimethylisoxazol-4-yl)-1H-pyrazol-4-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-[2-(3-Cyclopropylisoxazol-4-yl)-1,3-thiazol-4-yl]-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-{3-[2-(Difluoromethoxy)pyridin-4-yl]isoxazol-5-yl}-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-[4-(3-Cyclopropylisoxazol-4-yl)-1-methyl-1H-imidazol-2-yl]-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-2-(3′-Cyclopropyl-3,4′-biisoxazol-5-yl)-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-1,1-Difluoro-2-{4-[4-fluoro-2-(trifluoromethyl)phenyl]-1,3-oxazol-2-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(1S)-1-[3-(5-Chloro-2-methoxyphenyl)-1,2,4-oxadiazol-5-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(2S)-1,1-Difluoro-2-{3-[4-fluoro-2-(trifluoromethyl)phenyl]-1,2,4-oxadiazol-5-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

(2S)-2-(3-Cyclohexyl-1,2,4-oxadiazol-5-yl)-1,1-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

(2S)-1,1-Difluoro-2-[3-(3-fluorophenyl)-1,2,4-oxadiazol-5-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(2S)-1,1-Difluoro-2-[5-(2-methylphenyl)-1,3,4-oxadiazol-2-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

(2R)-1,1-Difluoro-2-[5-(2-methylphenyl)-1,3,4-thiadiazol-2-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

1-{3-[3-(Difluoromethoxy)phenyl]-1,2,4-oxadiazol-5-yl}-4-fluoro-6-azaspiro[2.5]octane-6-sulfonamide;

1-{3-[3-(Difluoromethoxy)phenyl]-1,2,4-oxadiazol-5-yl}-4-fluoro-6-azaspiro[2.5]octane-6-sulfonamide;

4,4-Difluoro-1-(3-phenyl-1,2,4-oxadiazol-5-yl)-6-azaspiro[2.5]octane-6-sulfonamide;

1-[3-(2,5-Dimethylphenyl)-1,2,4-oxadiazol-5-yl]-4,4-difluoro-6-azaspiro[2.5]octane-6-sulfonamide;

4-Methyl-1-{3-[2-(2,2,2-trifluoroethoxy)pyridin-4-yl]-1,2,4-oxadiazol-5-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

1-[3-(3-Cyclopropylisoxazol-4-yl)-1,2,4-oxadiazol-5-yl]-4-fluoro-6-azaspiro[2.5]octane-6-sulfonamide;

1-[3-(3-Cyclopropylisoxazol-4-yl)-1,2,4-oxadiazol-5-yl]-4-fluoro-6-azaspiro[2.5]octane-6-sulfonamide;

1-[3-(3-Cyclopropylisoxazol-4-yl)-1,2,4-oxadiazol-5-yl]-4-fluoro-6-azaspiro[2.5]octane-6-sulfonamide;

1-[3-(3-Cyclopropylisoxazol-4-yl)-1,2,4-oxadiazol-5-yl]-4-fluoro-6-azaspiro[2.5]octane-6-sulfonamide;

1-[3-(3-Cyclopropylisoxazol-4-yl)-1,2,4-oxadiazol-5-yl]-4-fluoro-6-azaspiro[2.5]octane-6-sulfonamide;

2-[3-(3-Cyclopropylisoxazol-4-yl)-1,2,4-oxadiazol-5-yl]-1,1,4-trifluoro-6-azaspiro[2.5]octane-6-sulfonamide;

2-[3-(3-Cyclopropylisoxazol-4-yl)-1,2,4-oxadiazol-5-yl]-1,1,4-trifluoro-6-azaspiro[2.5]octane-6-sulfonamide;

2-[3-(3-Cyclopropylisoxazol-4-yl)-1,2,4-oxadiazol-5-yl]-1,1,4-trifluoro-6-azaspiro[2.5]octane-6-sulfonamide;

2-[3-(3-Cyclopropylisoxazol-4-yl)-1,2,4-oxadiazol-5-yl]-1,1,4-trifluoro-6-azaspiro[2.5]octane-6-sulfonamide;

1,1,4-Trifluoro-2-{3-[4-fluoro-2-(trifluoromethyl)phenyl]-1,2,4-oxadiazol-5-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

1,1,4-Trifluoro-2-{3-[4-fluoro-2-(trifluoromethyl)phenyl]-1,2,4-oxadiazol-5-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

1,1,4-Trifluoro-2-{3-[4-fluoro-2-(trifluoromethyl)phenyl]-1,2,4-oxadiazol-5-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

1,1-Difluoro-2-{3-[4-fluoro-2-(trifluoromethyl)phenyl]-1,2,4-thiadiazol-5-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

1-Fluoro-2-{3-[4-fluoro-2-(trifluoromethyl)phenyl]-1,2,4-oxadiazol-5-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

1-{3-[4-Fluoro-2-(trifluoromethyl)phenyl]-1,2,4-oxadiazol-5-yl}-2-methyl-6-azaspiro[2.5]octane-6-sulfonamide;

2-{3-[4-Fluoro-2-(trifluoromethyl)phenyl]-1,2,4-oxadiazol-5-yl}-1,1-dimethyl-6-azaspiro[2.5]octane-6-sulfonamide;

1,1-Difluoro-2-{5-[4-fluoro-2-(trifluoromethyl)phenyl]isothiazol-3-yl}-6-azaspiro[2.5]octane-6-sulfonamide;

1,1-Difluoro-2-[5-(piperidin-1-yl)-1,2,4-thiadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

1,1-Difluoro-2-[5-(piperidin-1-yl)-1,2,4-thiadiazol-3-yl]-6-azaspiro[2.5]octane-6-sulfonamide;

3′-[5-(2,5-Dimethylphenyl)-1,2,4-oxadiazol-3-yl]-2′,2′-difluoro-3-azaspiro[bicyclo[3.2.1]octane-8,1′-cyclopropane]-3-sulfonamide; and

2-[5-(2,5-Dimethylphenyl)-1,2,4-oxadiazol-3-yl]-1,1-difluoro-5-methyl-6-azaspiro[2.5]octane-6-sulfonamide; or

a pharmaceutically acceptable salt thereof.

10. A pharmaceutical composition comprising (i) a pharmaceutically acceptable carrier and (ii) a compound of claim 1 or a pharmaceutically acceptable salt thereof.

11. The pharmaceutical composition of claim 10 , further comprising a therapeutic agent selected from the group consisting of acetylcholinesterase inhibitors; NMDA receptor antagonists; antipsychotics; MAO-B inhibitors; and levodopa.

12. A method of treating a patient with cognitive impairments associated with Alzheimer's disease, Parkinson's disease, and schizophrenia, the method comprising administering to the patient the compound of claim 1 or a pharmaceutically acceptable salt thereof, in an amount effective to treat the patient.

13. A compound which is

or a pharmaceutically acceptable salt thereof.

14. A compound according to claim 13 which is

15. A compound according to claim 13 which is a pharmaceutically acceptable salt of

16. A pharmaceutical composition comprising (i) a pharmaceutically acceptable carrier and (ii) the compound of claim 14 .

17. A pharmaceutical composition comprising (i) a pharmaceutically acceptable carrier and (ii) the compound of claim 15 .

18. A method of treating a patient with mild to moderate dementia of the Alzheimer's type, the method comprising administering to the patient the compound of claim 14 in an amount effective to treat the patient.

19. A compound which is

or a pharmaceutically acceptable salt thereof.

20. A compound according to claim 19 which is

21. A compound according to claim 19 which is a pharmaceutically acceptable salt of

22. A pharmaceutical composition comprising (i) a pharmaceutically acceptable carrier and (ii) the compound of claim 20 .

23. A pharmaceutical composition comprising (i) a pharmaceutically acceptable carrier and (ii) the compound of claim 21 .

24. A method of treating a patient with mild to moderate dementia of the Alzheimer's type, the method comprising administering to the patient the compound of claim 20 in an amount effective to treat the patient.

25. A compound which is

or a pharmaceutically acceptable salt thereof.

26. A compound according to claim 25 which is

27. A compound according to claim 25 which is a pharmaceutically acceptable salt of

28. A pharmaceutical composition comprising (i) a pharmaceutically acceptable carrier and (ii) the compound of claim 26 .

29. A pharmaceutical composition comprising (i) a pharmaceutically acceptable carrier and (ii) the compound of claim 27 .

30. A method of treating a patient with mild to moderate dementia of the Alzheimer's type, the method comprising administering to the patient the compound of claim 26 in an amount effective to treat the patient.

31. A compound which is

or a pharmaceutically acceptable salt thereof.

32. A compound according to claim 31 which is

33. A compound according to claim 31 which is a pharmaceutically acceptable salt of

34. A pharmaceutical composition comprising (i) a pharmaceutically acceptable carrier and (ii) the compound of claim 32 .

35. A pharmaceutical composition comprising (i) a pharmaceutically acceptable carrier and (ii) the compound of claim 33 .

36. A method of treating a patient with mild to moderate dementia of the Alzheimer's type, the method comprising administering to the patient the compound of claim 31 in an amount effective to treat the patient.

37. A compound which is

or a pharmaceutically acceptable salt thereof.

38. A compound according to claim 37 which is

39. A compound according to claim 37 which is a pharmaceutically acceptable salt of

40. A pharmaceutical composition comprising (i) a pharmaceutically acceptable carrier and (ii) the compound of claim 38 .

41. A pharmaceutical composition comprising (i) a pharmaceutically acceptable carrier and (ii) the compound of claim 39 .

42. A method of treating a patient with mild to moderate dementia of the Alzheimer's type, the method comprising administering to the patient the compound of claim 38 in an amount effective to treat the patient.

43. A compound which is

or a pharmaceutically acceptable salt thereof.

44. A compound according to claim 43 which is

45. A compound according to claim 43 which is a pharmaceutically acceptable salt of

46. A pharmaceutical composition comprising (i) a pharmaceutically acceptable carrier and (ii) the compound of claim 44 .

47. A pharmaceutical composition comprising (i) a pharmaceutically acceptable carrier and (ii) the compound of claim 45 .

48. A method of treating a patient with mild to moderate dementia of the Alzheimer's type, the method comprising administering to the patient the compound of claim 44 in an amount effective to treat the patient.

49. A compound which is

or a pharmaceutically acceptable salt thereof.

50. A compound according to claim 49 which is

51. A compound according to claim 49 which is a pharmaceutically acceptable salt of

52. A pharmaceutical composition comprising (i) a pharmaceutically acceptable carrier and (ii) the compound of claim 50 .

53. A pharmaceutical composition comprising (i) a pharmaceutically acceptable carrier and (ii) the compound of claim 51 .

54. A method of treating a patient with mild to moderate dementia of the Alzheimer's type, the method comprising administering to the patient the compound of claim 50 in an amount effective to treat the patient.