Substituted pyridopyrimidinonyl compounds useful as T cell activators

1. A compound or a pharmaceutically acceptable salt thereof, having the structure:

wherein:

R 1 is Cl or —CN;

R 2 is —CH 3 or —CD 3 ;

R 4 is —CHR 4a R 4b ;

R 4a is cyclopropyl, cyclobutyl, cyclohexyl, phenyl, pyridinyl, pyrimidinyl, oxadiazolyl, bicyclo[1.1.1]pentanyl, benzo[d][1,3]dioxolyl, or oxodihydrobenzo[d]oxazolyl, each substituted with zero to 3 substituents independently selected from F, Cl, Br, —CN, —CH 3 , —CH(CH 3 ) 2 , —C(CH 3 ) 3 , —CH 2 OH, —CHF 2 , —CF 3 , —CH 2 Br, —CH 2 NH 2 , —CH 2 NHC(O)OCH 3 , —C(CH 3 ) 2 CN, —OCH 3 , —OCD 3 , —OCH 2 CH 3 , —OCH(CH 3 ) 2 , —OCHF 2 , —OCF 3 , —OCH 2 CH 2 CF 3 , —OC(CH 3 ) 2 CN, —OC(CH 3 ) 2 CH 2 OH, —OC(CH 3 ) 2 CH 2 OCH 3 , —N(CH 3 ) 2 , —C(O)OCH 3 , cyclopropyl, cyanocyclopropyl, methylcyclopropyl, —O(cyclopropyl), —O((ethoxycarbonyl)cyclopropyl), morpholinyl, pyrrolidinonyl, tetrahydropyranyl, dioxolanyl, —CH 2 (morpholinyl), —CH 2 (difluoromorpholinyl), —CH 2 (dimethylmorpholinyl), —CH 2 (oxaazabicyclo[2.2.1]heptanyl), —CH 2 (oxaazaspiro[3.3]heptanyl), —CH 2 (methylpiperazinonyl), —CH 2 (acetylpiperazinyl), —CH 2 (piperidinyl), —CH 2 (difluoropiperidinyl), —CH 2 (methoxypiperidinyl), —CH 2 (hydroxypiperidinyl), —C(CH 3 ) 2 (morpholinyl), —OCH 2 (cyclopropyl), —OCH 2 (methylcyclopropyl), —OCH 2 (methylazetidinyl), —OCH 2 (oxetanyl), —OCH 2 (tetrahydropyranyl), —OCH 2 (thiazolyl), and —OCH 2 CH 2 (cyclopropyl);

R 4b is:

(i) —CN, —CH 3 , —CH 2 CH 3 , —CH 2 CH 2 CH 3 , or —CH(CH 3 ) 2 ; or

(ii) phenyl, isoxazolyl, oxadiazolyl, thiazolyl, or triazolyl, each substituted with zero to 3 substituents independently selected from F, Cl, Br, —CH 3 , —C(CH 3 ) 3 , —CF 3 , —OCF 3 , and cyclopropyl; and

R 5a is —CH 3 or —CH 2 CH 3 ; and

R 5c is —CH 3 , —CH 2 CH 3 , or —CH 2 CH 2 CH 3 .

2. The compound according to claim 1 or a pharmaceutically acceptable salt thereof, wherein:

R 4a is phenyl, pyridinyl, pyrimidinyl, oxadiazolyl, benzo[d][1,3]dioxolyl, or oxodihydrobenzo[d]oxazolyl, each substituted with 1 to 3 substituents independently selected from F, Cl, Br, —CN, —CH 3 , —CH 2 OH, —CH 2 Br, —CH 2 NH 2 , —CH 2 NHC(O)OCH 3 , —CF 3 , —C(CH 3 ) 2 CN, —OCH 3 , —OCD 3 , —OCH 2 CH 3 , —OCH(CH 3 ) 2 , —OCHF 2 , —OCF 3 , —OCH 2 CH 2 CF 3 , —OC(CH 3 ) 2 CN, —OC(CH 3 ) 2 CH 2 OH, —OC(CH 3 ) 2 CH 2 OCH 3 , —N(CH 3 ) 2 , —C(O)OCH 3 , cyclopropyl, cyanocyclopropyl, methylcyclopropyl, —O(cyclopropyl), —O((ethoxycarbonyl)cyclopropyl), —OCH 2 (cyclopropyl), —CH 2 (piperidinyl), morpholinyl, pyrrolidinonyl, tetrahydropyranyl, dioxolanyl, —CH 2 (morpholinyl), —CH 2 (difluoromorpholinyl), —CH 2 (dimethylmorpholinyl), —CH 2 (oxaazabicyclo[2.2.1]heptanyl), —CH 2 (oxaazaspiro[3.3]heptanyl), —CH 2 (methylpiperazinonyl), —CH 2 (acetylpiperazinyl), —CH 2 (piperidinyl), —CH 2 (difluoropiperidinyl), —CH 2 (methoxypiperidinyl), —CH 2 (hydroxypiperidinyl), —C(CH 3 ) 2 (morpholinyl), —OCH 2 (cyclopropyl), —OCH 2 (methylcyclopropyl), —OCH 2 (methylazetidinyl), —OCH 2 (oxetanyl), —OCH 2 (tetrahydropyranyl), —OCH 2 (thiazolyl), and —OCH 2 CH 2 (cyclopropyl); and

R ab is —CN, —CH 3 , —CH 2 CH 3 , —CH 2 CH 2 CH 3 , or —CH(CH 3 ) 2 .

3. The compound according to claim 1 or a pharmaceutically acceptable salt thereof, having the structure:

R 4a is phenyl, pyridinyl, or oxadiazolyl, each substituted zero to 3 substituents independently selected from with F, Cl, Br, —CN, —CH 3 , —C(CH 3 ) 3 , —CHF 2 , —CF 3 , —OCH 3 , —OCH(CH 3 ) 2 , —OCHF 2 , —OCF 3 , —OCH 2 (cyclopropyl), and cyclopropyl; and

R 4b is phenyl, isoxazolyl, thiazolyl, or triazolyl, each substituted with 0 to 3 substituents independently selected from F, Cl, Br, —CH 3 , —C(CH 3 ) 3 , —CF 3 , —OCF 3 , and cyclopropyl.

4. The compound according to claim 1 or a pharmaceutically acceptable salt thereof, wherein:

R 5a is —CH 3 or —CH 2 CH 3 ; and

R 5c is —CH 2 CH 3 or —CH 2 CH 2 CH 3 .

5. The compound according to claim 1 or a pharmaceutically acceptable salt thereof, having the structure:

6. The compound according to claim 1 or a pharmaceutically acceptable salt thereof, wherein said compound is:

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

4-((2S,5R)-2,5-diethyl-4-((4-fluorophenyl)(5-(trifluoromethyl)pyridin-2-yl)methyl) piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (1-2);

4-((2s, 5r)-4-(1-(4-cyclopropylphenyl)ethyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (3-4);

4-((2S,5R)-2,5-diethyl-4-(1-(4-(trifluoromethyl)phenyl)propyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (5-6);

4-((2S,5R)-5-ethyl-2-methyl-4-(1-(4-(trifluoromethyl)phenyl)ethyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (7-8);

4-((2S,5R)-2,5-diethyl-4-(1-(4-(trifluoromethoxy)phenyl)ethyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (9-10);

4-((2S,5R)-2,5-diethyl-4-(1-(2-fluoro-4-methoxyphenyl)propyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (11-12);

4-((2 S,5R)-4-(1-(2,2-difluorobenzo[d][1,3]dioxol-5-yl)ethyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (14-15);

4-((2S,5R)-2,5-diethyl-4-(1-(4-methoxyphenyl)ethyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (16-17);

4-((2S,5R)-2,5-diethyl-4-(1-(4-isopropoxyphenyl)ethyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (18-19);

4-((2S,5R)-2,5-diethyl-4-(1-(4-(trifluoromethyl)phenyl)ethyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (20-21);

4-((2S,5R)-2,5-diethyl-4-(4-(trifluoromethoxy)benzyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (22);

4-((2S,5R)-4-(1-(4-(cyclopropylmethoxy)phenyl)ethyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (23-24);

4-((2S,5R)-2,5-diethyl-4-(1-(2-fluoro-4-(trifluoromethyl)phenyl)ethyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (25-26);

4-((2S,5R)-4-(1-(4-cyclopropylphenyl)ethyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (28-29);

4-((2S,5R)-2,5-diethyl-4-(1-(3-fluoro-4-(trifluoromethoxy)phenyl)ethyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (30-31);

4-((2S,5R)-4-(1-(4-(cyclopropylmethoxy)-2-fluorophenyl)ethyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (32-33);

4-((2S,5R)-2,5-diethyl-4-((4-fluorophenyl)(isoxazol-3-yl)methyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (34-35);

4-((2S,5R)-2,5-diethyl-4-(1-(4-(trifluoromethoxy)phenyl)propyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (36-37);

4-((2S,5R)-2,5-diethyl-4-(1-(2-fluoro-4-(trifluoromethoxy)phenyl)ethyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (38-39);

4-((2S,5R)-4-(1-(4-cyclopropyl-2-fluorophenyl)ethyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (40-41);

4-((2S,5R)-4-((5-cyclopropylisoxazol-3-yl)(4-(trifluoromethoxy)phenyl)methyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (42-43);

4-((2 S,5R)-2,5-diethyl-4-(1-(6-(trifluoromethyl)pyridin-3-yl)ethyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (44-45);

4-((2S,5R)-5-ethyl-4-(4-fluorophenyl)(5-(trifluoromethyl)pyridin-2-yl)methyl)-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (46-47);

4-((2S,5R)-5-ethyl-2-methyl-4-(1-(4-(trifluoromethoxy)phenyl)ethyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (48-49);

4-((2S,5R)-4-((4-cyclopropylthiazol-2-yl)(4-fluorophenyl)methyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (50-51);

4-((2S,5R)-5-ethyl-4-(1-(4-isopropoxyphenyl)ethyl)-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (52-53);

4-((2S,5R)-5-ethyl-4-(1-(4-methoxyphenyl)ethyl)-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (56-57);

4-((2S,5R)-5-ethyl-4-(1-(2-fluoro-4-(trifluoromethyl)phenyl)ethyl)-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (58-59);

4-((2S,5R)-4-(1-(4-cyanophenyl)ethyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (60-61);

4-((2S,5R)-4-(1-(4-cyclopropylphenyl)ethyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (63-64);

4-((2S,5R)-5-ethyl-4-(4-fluorophenyl)(6-(trifluoromethyl)pyridin-2-yl)methyl)-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (65-66);

4-((2S,5R)-4-(1-(4-(cyclopropylmethoxy)phenyl)ethyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (67-68);

4-((2S,5R)-4-(1-(4-(cyclopropylmethoxy)-2-fluorophenyl)ethyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (69-70);

4-((2 S,5R)-4-(1-(2,2-difluorobenzo[d][1,3]dioxol-5-yl)ethyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (71-72);

4-((2S,5R)-5-ethyl-4-(4-fluorophenyl)(isoxazol-3-yl)methyl)-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (73-74);

4-((2S,5R)-4-((5-cyclopropylpyridin-2-yl)(4-fluorophenyl)methyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (75-76);

4-((2S,5R)-4-(1-(4-(difluoromethoxy)phenyl)propyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (77-78);

4-((2 S,5R)-4-(1-(2,2-difluorobenzo[d][1,3]dioxol-5-yl)propyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (79-80);

4-((2S,5R)-5-ethyl-4-(1-(2-fluoro-4-(trifluoromethoxy)phenyl)ethyl)-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (81-82);

4-((2S,5R)-5-ethyl-2-methyl-4-(1-(4-(trifluoromethoxy)phenyl)propyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (83-84);

4-((2S,5R)-5-ethyl-4-(1-(2-fluoro-4-(trifluoromethoxy)phenyl)propyl)-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (85-86);

4-((2S,5R)-5-ethyl-4-(4-fluorophenyl)(pyridin-2-yl)methyl)-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (87-88);

4-((2S,5R)-5-ethyl-2-methyl-4-(1-(4-(trifluoromethyl)phenyl)propyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (89-90);

4-((2S,5R)-4-(1-(4-cyclopropyl-2-fluorophenyl)ethyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (91-92);

4-((2S,5R)-5-ethyl-2-methyl-4-(pyridin-2-yl(4-(trifluoromethoxy)phenyl)methyl) piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (93-94);

4-((2S,5R)-4-((4-chlorophenyl)(pyridin-2-yl)methyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (95-96);

4-((2 S,5R)-5-ethyl-4-(4-fluorophenyl)(6-(trifluoromethyl)pyridin-3-yl)methyl)-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (97-98);

4-((2S,5R)-4-((5-cyclopropylisoxazol-3-yl)(4-(trifluoromethoxy)phenyl)methyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (99-100);

4-((2S,5R)-4-((5-cyclopropylisoxazol-3-yl)(4-fluorophenyl)methyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (101-102);

4-((2S,5R)-4-((2-cyclopropylthiazol-5-yl)(4-fluorophenyl)methyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (103-104);

6-chloro-4-((2S,5R)-4-((3-cyclopropyl-1,2,4-oxadiazol-5-yl)(4-fluorophenyl)methyl)-2,5-dimethylpiperazin-1-yl)-1-methylpyrido[3,2-d]pyrimidin-2(1H)-one (105);

4-((2S,5R)-4-((3-cyclopropyl-1,2,4-oxadiazol-5-yl)(4-fluorophenyl)methyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (106-107);

4-((2S,5R)-4-((3-(tert-butyl)-1,2,4-oxadiazol-5-yl)(4-fluorophenyl)methyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (108-109);

4-((2S,5R)-4-((3-cyclopropyl-1,2,4-oxadiazol-5-yl)(4-fluorophenyl)methyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (110-111);

4-((2S,5R)-4-((3-cyclopropyl-1,2,4-oxadiazol-5-yl)(4-fluorophenyl)methyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (112-113);

4-((2S,5R)-2-ethyl-4-((4-fluorophenyl)(5-(trifluoromethyl)pyridin-2-yl)methyl)-5-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (114-115);

4-((2S,5R)-2-ethyl-5-methyl-4-(1-(4-(trifluoromethyl)phenyl)ethyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (116-117);

4-((2S,5R)-2-ethyl-4-(1-(2-fluoro-4-(trifluoromethyl)phenyl)ethyl)-5-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (118-119);

4-((2S,5R)-2-ethyl-4-((4-fluorophenyl)(6-(trifluoromethyl)pyridin-2-yl)methyl)-5-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (120-121);

4-((2S,5R)-2-ethyl-5-methyl-4-(1-(4-(trifluoromethoxy)phenyl)ethyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (122-123);

4-((2 S,5R)-4-(bis(4-fluorophenyl)methyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (124-125);

4-((2S,5R)-4-(4-fluorophenyl)(5-(trifluoromethyl)pyridin-2-yl)methyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (126-127);

4-((2S,5R)-4-(1-(4-fluorophenyl)ethyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (128-129);

4-((2S,5R)-2,5-dimethyl-4-(1-(4-(trifluoromethoxy)phenyl)ethyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (131-132);

4-((2S,5R)-2,5-dimethyl-4-(1-(3,4,5-trifluorophenyl)ethyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (138-139);

4-((2S,5R)-2,5-dimethyl-4-(1-(4-(trifluoromethyl)phenyl)ethyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (140-141);

4-((2S,5R)-4-(1-(2-fluoro-4-(trifluoromethoxy)phenyl)ethyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (142-143);

4-((2 S,5R)-4-(1-(2,4-difluorophenyl)ethyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (144-145);

4-((2S,5R)-4-(1-(4-chloro-2-fluorophenyl)ethyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (146-147);

4-((2S,5R)-4-(1-(3,4-difluorophenyl)ethyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (148-149);

4-((2S,5R)-4-(1-(2-fluoro-4-(trifluoromethyl)phenyl)ethyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (150-151);

4-((2S,5R)-4-(1-(2-fluoro-4-(trifluoromethoxy)phenyl)propyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (152-153);

4-((2S,5R)-2,5-dimethyl-4-(1-(4-(trifluoromethoxy)phenyl)propyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (154-155);

4-((2S,5R)-4-(1-(4-(difluoromethoxy)phenyl)ethyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (156-157);

4-((2S,5R)-4-((4-cyclopropylthiazol-2-yl)(4-fluorophenyl)methyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (158-159);

4-((2S,5R)-4-(1-(3-fluoro-4-(trifluoromethoxy)phenyl)ethyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (160-161);

4-((2S,5R)-4-((4-fluorophenyl)(isoxazol-3-yl)methyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (162-163);

4-((2S,5R)-4-((5-cyclopropylisoxazol-3-yl)(4-(trifluoromethoxy)phenyl)methyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (164-165);

4-((2 S,5R)-4-(1-(2,2-difluorobenzo[d][1,3]dioxol-5-yl)ethyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (166-167);

4-((2S,5R)-4-(1-(4-cyclopropyl-2-fluorophenyl)ethyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (168-169);

4-((2S,5R)-4-((4-fluorophenyl)(2-(trifluoromethyl)thiazol-4-yl)methyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (170-171);

6-chloro-4-((2S,5R)-2,5-diethyl-4-(1-(4-((1-hydroxy-2-methylpropan-2-yl)oxy) phenyl)ethyl)piperazin-1-yl)-1-methylpyrido[3,2-d]pyrimidin-2(1H)-one (186);

6-chloro-4-((2S,5R)-2,5-diethyl-4-(1-(4-((1-methoxy-2-methylpropan-2-yl)oxy) phenyl)ethyl)piperazin-1-yl)-1-methylpyrido[3,2-d]pyrimidin-2(1H)-one (187);

6-chloro-4-((2S,5R)-2,5-diethyl-4-(1-(4-((1-methoxy-2-methylpropan-2-yl)oxy) phenyl)ethyl)piperazin-1-yl)-1-methylpyrido[3,2-d]pyrimidin-2(1H)-one (188-189);

4-((2S,5R)-2,5-diethyl-4-(1-(4-(methoxy-d3)phenyl)ethyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (190-191);

4-((2 S,5R)-4-(1-(6-cyclopropylpyridin-3-yl)ethyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (192-193);

4-((2S,5R)-2,5-diethyl-4-(1-(2-morpholino-4-(trifluoromethyl)phenyl)ethyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (194-195);

4-((2S,5R)-4-(1-(4-(2-cyanopropan-2-yl)phenyl)ethyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (196-197);

4-((2S,5R)-4-(1-(4-(cyclopropylmethoxy)-2-fluorophenyl)propyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (198-199);

4-((2S,5R)-4-(1-(4-cyclopropylphenyl)propyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (200-201);

4-((2S,5R)-2,5-diethyl-4-(1-(3-methyl-2-oxo-2,3-dihydrobenzo[d]oxazol-5-yl)ethyl) piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (202-203);

4-((2 S,5R)-2,5-diethyl-4-(1-(2-morpholinopyrimidin-5-yl)ethyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (206-207);

4-((2S,5R)-2,5-diethyl-4-(1-(4-(methoxy-d3)phenyl)propyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (208-209);

4-((2S,5R)-2,5-diethyl-4-(4-fluorophenyl)(2-(trifluoromethyl)thiazol-4-yl)methyl) piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (210-211);

4-((2S,5R)-2,5-diethyl-4-(1-(4-methoxyphenyl)propyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (212-213);

4-((2 S,5R)-2,5-diethyl-4-(1-(6-methoxypyridin-2-yl)ethyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (214-215);

4-((2S,5R)-4-(1-(4-(cyclopropylmethoxy)phenyl)propyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (216-217);

4-((2S,5R)-2,5-diethyl-4-(1-(4-(1-methylcyclopropyl)phenyl)ethyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (218-219);

4-((2 S,5R)-4-(1-(4-cyanophenyl)propyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (220-221);

4-((2S,5R)-4-(1-(4-(difluoromethoxy)phenyl)propyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (222-223);

4-((2 S,5R)-2,5-diethyl-4-(1-(6-(trifluoromethyl)pyridin-3-yl)propyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (224-225);

4-((2 S,5R)-2,5-diethyl-4-(1-(2-(trifluoromethyl)pyrimidin-5-yl)ethyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (226-227);

4-((2 S,5R)-2,5-diethyl-4-(1-(6-methylpyridin-3-yl)ethyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (228-229);

4-((2S,5R)-2,5-diethyl-4-(1-(4-(2-oxopyrrolidin-1-yl)phenyl)ethyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (230-231);

4-((2 S,5R)-4-(1-(4-(difluoromethoxy)-2-fluorophenyl)propyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (232-233);

4-((2 S,5R)-2,5-diethyl-4-(1-(4-isopropoxyphenyl)propyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (234-235);

4-((2S,5R)-2,5-diethyl-4-(1-(p-tolyl)propyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (236-237);

4-((2 S,5R)-4-(1-(4-chloro-2-fluorophenyl)propyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (238-239);

4-((2 S,5R)-4-(1-(6-(difluoromethoxy)pyridin-2-yl)ethyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (240-241);

4-((2S,5R)-2,5-diethyl-4-(1-(4-(trifluoromethyl)phenyl)butyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (243-244);

4-((2 S,5R)-2,5-diethyl-4-(1-(6-(trifluoromethoxy)pyridin-2-yl)ethyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (245-246);

4-((2 S,5R)-2,5-diethyl-4-(1-(4-(2-morpholinopropan-2-yl)phenyl)ethyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (247-248);

4-((2S,5R)-2,5-diethyl-4-(1-(4-methoxyphenyl)-2-methylpropyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (249-250);

4-((2S,5R)-4-(1-(4-(2-cyanopropan-2-yl)phenyl)propyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (251-252);

4-((2S,5R)-4-(1-(2-cyclopropylbenzo[d]oxazol-5-yl)ethyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (253-254);

4-((2S,5R)-4-(1-(4-cyclopropoxyphenyl)propyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (255-256);

4-((2S,5R)-4-((6-(difluoromethyl)pyridin-2-yl)(4-fluorophenyl)methyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (257-258);

ethyl (1 S,2S)-2-(4-(1-((2R,5 S)-4-(6-cyano-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidin-4-yl)-2,5-diethylpiperazin-1-yl)ethyl)phenoxy)cyclopropane-1-carboxylate (259-260);

4-((2 S,5R)-2,5-diethyl-4-(1-(4-isopropoxyphenyl)-2-methylpropyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (261-262);

4-((2S,5R)-4-(1-(4-(1-cyanocyclopropyl)phenyl)ethyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (263-264);

methyl 4-(1-((2R,5S)-4-(6-cyano-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidin-4-yl)-2,5-diethylpiperazin-1-yl)ethyl)benzoate (265-266);

4-((2S,5R)-2,5-diethyl-4-(1-(4-(morpholinomethyl)phenyl)propyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (267-268);

4-((2S,5R)-2,5-diethyl-4-(1-(4-(hydroxymethyl)phenyl)ethyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (270-271);

4-((2S,5R)-4-(1-(4-(Bromomethyl)phenyl)ethyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (272);

4-((2S,5R)-2,5-diethyl-4-(1-(4-((4-methoxypiperidin-1-yl)methyl)phenyl)ethyl) piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (273-274);

4-((2S,5R)-4-(1-(4-((2,2-dimethylmorpholino)methyl)phenyl)ethyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (275-276);

4-((2S,5R)-4-(1-(4-((4,4-difluoropiperidin-1-yl)methyl)phenyl)ethyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (277-278);

4-((2S,5R)-4-(1-(4-((2-oxa-6-azaspiro[3.3]heptan-6-yl)methyl)phenyl)ethyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (279-280);

4-((2S,5R)-2,5-diethyl-4-(1-(4-(piperidin-1-ylmethyl)phenyl)ethyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (281-282);

4-((2S,5R)-4-(1-(4-((4-acetylpiperazin-1-yl)methyl)phenyl)ethyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (283-284);

4-((2S,5R)-2,5-diethyl-4-(1-(4-((4-hydroxypiperidin-1-yl)methyl)phenyl)ethyl) piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (285-286);

4-((2S,5R)-2,5-diethyl-4-(1-(4-((4-methyl-3-oxopiperazin-1-yl)methyl)phenyl)ethyl) piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (287-288);

4-((2S,5R)-2,5-diethyl-4-(1-(4-(((R)-3-hydroxypiperidin-1-yl)methyl)phenyl)ethyl) piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (289-290);

4-((2S,5R)-4-(1-(4-(((2S,6R)-2,6-dimethylmorpholino)methyl)phenyl)ethyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (291-292);

4-((2S,5R)-4-((3-bromo-1-methyl-1H-1,2,4-triazol-5-yl)(4-fluorophenyl)methyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (293);

4-((2S,5R)-4-((3-cyclopropyl-1-methyl-1H-1,2,4-triazol-5-yl)(4-fluorophenyl) methyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (294-295);

4-((2S,5R)-5-ethyl-4-((4-fluorophenyl)(2-(trifluoromethyl)thiazol-4-yl)methyl)-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (296-297);

4-((2S,5R)-5-ethyl-2-methyl-4-(1-(3-methyl-2-oxo-2,3-dihydrobenzo[d]oxazol-5-yl) ethyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (298-299);

4-((2S,5R)-4-(1-(4-cyclopropylphenyl)propyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (300-301);

4-((2S,5R)-4-(1-(4-cyclopropyl-2-fluorophenyl)propyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (302-303);

4-((2S,5R)-5-ethyl-4-(1-(4-methoxyphenyl)propyl)-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (304-305);

4-((2S,5R)-4-(1-(4-ethoxyphenyl)propyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (306-307);

4-((2S,5R)-4-(1-(4-(cyclopropylmethoxy)phenyl)propyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (308-309);

4-((2S,5R)-4-(1-(4-cyclopropoxyphenyl)propyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (311-312);

4-((2S,5R)-5-ethyl-4-(1-(4-methoxyphenyl)-2-methylpropyl)-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (313-314);

4-((2S,5R)-4-((6-(difluoromethyl)pyridin-2-yl)(4-fluorophenyl)methyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (315-316);

4-((2S,5R)-4-(1-(4-(2-cyanopropan-2-yl)phenyl)propyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (317-318);

4-((2S,5R)-4-(1-(3,4-difluorophenyl)propyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (319-320);

4-((2S,5R)-4-(1-(4-bromophenyl)propyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (321-322);

4-((2S,5R)-5-ethyl-4-(1-(4-isopropoxyphenyl)-2-methylpropyl)-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (323-324);

4-((2 S,5R)-4-(1-(4-(1-cyanocyclopropyl)phenyl)ethyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (325-326);

4-((2S,5R)-4-(1-(4-(cyclopropylmethoxy)-2,6-difluorophenyl)propyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (327-328);

4-((2S,5R)-5-ethyl-2-methyl-4-(1-(4-(tetrahydro-2H-pyran-4-yl)phenyl)ethyl) piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (329-330);

4-((2S,5R)-4-(1-(4-(1,3-dioxolan-2-yl)phenyl)propyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (331-332);

4-((2S,5R)-5-ethyl-4-(1-(4-isopropoxyphenyl)propyl)-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (330-334);

4-((2S,5R)-5-ethyl-2-methyl-4-(1-(4-(3,3,3-trifluoropropoxy)phenyl)propyl) piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (335-336);

4-((2S,5R)-5-ethyl-2-methyl-4-(1-(4-((tetrahydro-2H-pyran-4-yl)methoxy)phenyl) propyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (337-338);

4-((2S,5R)-4-(1-(4-(2-cyclopropylethoxy)phenyl)propyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (339-340);

4-((2S,5R)-5-ethyl-2-methyl-4-(1-(4-(oxetan-3-ylmethoxy)phenyl)propyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (341-342);

4-((2 S,5R)-5-ethyl-2-methyl-4-(1-(4-((1-methylazetidin-3-yl)methoxy)phenyl)propyl) piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (343-344);

4-((2S,5R)-5-ethyl-2-methyl-4-(1-(4-((1-methylcyclopropyl)methoxy)phenyl)propyl) piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (345-346);

4-((2S,5R)-5-ethyl-2-methyl-4-(1-(4-(thiazol-2-ylmethoxy)phenyl)propyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (347-348);

4-((2S,5R)-4-(1-(3-bromo-4-(trifluoromethyl)phenyl)ethyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (349);

4-((2S,5R)-5-ethyl-2-methyl-4-(1-(3-(morpholinomethyl)-4-(trifluoromethyl)phenyl) ethyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d] pyrimidine-6-carbonitrile (350-351);

4-((2S,5R)-4-(1-(3-((dimethylamino)methyl)-4-(trifluoromethyl)phenyl)ethyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (352-353);

4-((2S,5R)-5-ethyl-2-methyl-4-(1-(3-(piperidin-1-ylmethyl)-4-(trifluoromethyl) phenyl)ethyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (354-355);

4-((2S,5R)-4-(1-(3-cyano-4-(trifluoromethyl)phenyl)ethyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (356-357);

4-((2S,5R)-4-(1-(4-(aminomethyl)phenyl)ethyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (358);

methyl (4-(1-((2R,5S)-4-(6-cyano-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidin-4-yl)-2-ethyl-5-methylpiperazin-1-yl)ethyl)benzyl)carbamate (359-360);

4-((2S,5R)-4-(1-(3-cyclopropyl-1,2,4-oxadiazol-5-yl)ethyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (361-362);

4-((2S,5R)-4-(1-(3-cyclopropyl-1,2,4-oxadiazol-5-yl)propyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (363-364);

4-((2S,5R)-4-(1-(3-cyclopropyl-1,2,4-oxadiazol-5-yl)-2-methylpropyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (365-366);

4-((2S,5R)-4-(1-(5-cyclopropyl-1,3,4-oxadiazol-2-yl)-2-methylpropyl)-5-ethyl-2-methylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (367-368);

2-((2R,5S)-4-(6-chloro-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidin-4-yl)-2,5-diethylpiperazin-1-yl)-2-(4-fluorophenyl)acetonitrile (369);

6-chloro-4-((2S,5R)-4-((5-cyclopropyl-1,2,4-oxadiazol-3-yl)(4-fluorophenyl)methyl)-2,5-diethylpiperazin-1-yl)-1-methylpyrido[3,2-d]pyrimidin-2(1H)-one (370);

4-((2S,5R)-4-((5-cyclopropyl-1,2,4-oxadiazol-3-yl)(4-fluorophenyl)methyl)-2,5-diethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (371-372);

4-((2S,5R)-4-(bis(4-chlorophenyl)methyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (373-374);

4-((2S,5R)-4-((4-cyanophenyl)(4-fluorophenyl)methyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (375);

4-((2S,5R)-4-(1-(4-((2-cyanopropan-2-yl)oxy)phenyl)ethyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (376-377);

4-((2S,5R)-4-(1-(4-cyclopropylphenyl)propyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (378-379);

4-((2S,5R)-4-(1-(4-cyclopropyl-2-fluorophenyl)propyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (380-381);

6-chloro-4-((2S,5R)-4-(1-(4-(hydroxymethyl)phenyl)ethyl)-2,5-dimethylpiperazin-1-yl)-1-methylpyrido[3,2-d]pyrimidin-2(1H)-one (382);

4-((2S,5R)-4-(1-(4-(hydroxymethyl)phenyl)ethyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (383);

4-((2S,5R)-4-(1-(4-(bromomethyl)phenyl)ethyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (384);

4-((2S,5R)-4-(1-(4-((2,2-dimethylmorpholino)methyl)phenyl)ethyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (385-386);

4-((2S,5R)-4-(1-(4-(((1S,4S)-2-oxa-5-azabicyclo[2.2.1]heptan-5-yl)methyl) phenyl)ethyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d] pyrimidine-6-carbonitrile (387-388);

4-((2S,5R)-4-(1-(4-(((2S,6R)-2,6-dimethylmorpholino)methyl)phenyl)ethyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (389);

4-((2 S,5R)-4-(1-(4-((4,4-difluoropiperidin-1-yl)methyl)phenyl)ethyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (390-391);

4-((2S,5R)-4-(1-(4-((2-oxa-6-azaspiro[3.3]heptan-6-yl)methyl)phenyl)ethyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (392-393);

6-chloro-1-methyl-4-((2S,5R)-2-methyl-5-propyl-4-(1-(4-(trifluoromethyl)phenyl) ethyl)piperazin-1-yl)pyrido[3,2-d]pyrimidin-2(1H)-one (394);

1-methyl-4-((2S,5R)-2-methyl-5-propyl-4-(1-(4-(trifluoromethyl)phenyl)ethyl) piperazin-1-yl)-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (395-396);

6-chloro-4-((2S,5R)-5-ethyl-2-methyl-4-(1-(4-(trifluoromethyl)phenyl)ethyl) piperazin-1-yl)-1-(methyl-d 3 )pyrido[3,2-d]pyrimidin-2(1H)-one (417-418);

4-((2S,5R)-5-ethyl-2-methyl-4-(1-(4-(trifluoromethyl)phenyl)ethyl)piperazin-1-yl)-1-(methyl-d3)-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (419-420);

6-chloro-4-((2S,5R)-2,5-diethyl-4-(1-(4-(trifluoromethyl)phenyl)propyl)piperazin-1-yl)-1-methylpyrido[3,2-d]pyrimidin-2(1H)-one (421-422);

6-chloro-4-((2S,5R)-2,5-diethyl-4-(1-(4-(trifluoromethyl)phenyl)ethyl)piperazin-1-yl)-1-methylpyrido[3,2-d]pyrimidin-2(1H)-one (426);

6-chloro-4-((2S,5R)-2,5-dimethyl-4-(1-(3-(trifluoromethyl)bicyclo[1.1.1]pentan-1-yl)propyl)piperazin-1-yl)-1-methylpyrido[3,2-d]pyrimidin-2(1H)-one (Diastereomeric Mixture) (446);

4-((2S,5R)-2,5-dimethyl-4-(1-(3-(trifluoromethyl)bicyclo[1.1.1]pentan-1-yl)propyl) piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (447-449);

4-((2S,5R)-4-((4-fluorophenyl)(3-(trifluoromethyl)bicyclo[1.1.1]pentan-1-yl)methyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (450-452);

4-((2 S,5R)-4-(1-cyclopropylpropyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (453-455);

4-((2S,5R)-4-(1-(3,3-difluorocyclobutyl)propyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (456-458); or

4-((2S,5R)-4-(1-(4,4-difluorocyclohexyl)propyl)-2,5-dimethylpiperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile (459-460).

8. The compound according to claim 1 or a pharmaceutically acceptable salt thereof, having the structure:

9. The compound according to claim 1 or a pharmaceutically acceptable salt thereof, having the structure:

10. The compound according to claim 9 or a pharmaceutically acceptable salt thereof, wherein:

R 1 is —CN;

R 2 is —CH 3 ; and

R 4b is —CH 3 , —CH 2 CH 3 , or —CH 2 CH 2 CH 3 .

11. A compound having the structure:

or a pharmaceutically acceptable salt thereof.

12. The compound according to claim 11 or a pharmaceutically acceptable salt thereof, having the structure:

13. A compound having the structure:

or a pharmaceutically acceptable salt thereof.

14. The compound according to claim 13 or a pharmaceutically acceptable salt thereof, having the structure:

15. A compound having the structure:

or a pharmaceutically acceptable salt thereof.

16. The compound according to claim 15 or a pharmaceutically acceptable salt thereof, having the structure:

17. The compound according to claim 1 or a pharmaceutically acceptable salt thereof, wherein said compound is:

4-((2 S, 5R)-2,5-diethyl-4-((S)-1-(4-(trifluoromethyl)phenyl)propyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile;

4-((2 S, 5R)-2,5-diethyl-4-((R)-1-(4-(trifluoromethyl)phenyl)propyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile;

4-((2 S, 5R)-2,5-diethyl-4-((S)-1-(4-(trifluoromethoxy)phenyl)propyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile;

4-((2 S, 5R)-2,5-diethyl-4-((R)-1-(4-(trifluoromethoxy)phenyl)propyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile;

4-((2 S, 5R)-2,5-diethyl-4-((S)-1-(4-(trifluoromethyl)phenyl)butyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile; or

4-((2 S, 5R)-2,5-diethyl-4-((R)-1-(4-(trifluoromethyl)phenyl)butyl)piperazin-1-yl)-1-methyl-2-oxo-1,2-dihydropyrido[3,2-d]pyrimidine-6-carbonitrile.

18. A compound having the structure:

or a pharmaceutically acceptable salt thereof.

19. A compound having the structure:

20. A pharmaceutically acceptable salt of the compound having the structure:

21. A compound having the structure:

or a pharmaceutically acceptable salt thereof.

22. A compound having the structure:

23. A pharmaceutically acceptable salt of the compound having the structure:

24. A compound having the structure:

or a pharmaceutically acceptable salt thereof.

25. A compound having the structure:

26. A pharmaceutically acceptable salt of the compound having the structure:

27. A pharmaceutical composition comprising a compound according to claim 1 or a pharmaceutically-acceptable salt thereof; and a pharmaceutically acceptable carrier.

28. A pharmaceutical composition comprising a compound according to claim 19 ; and a pharmaceutically acceptable carrier.

29. A pharmaceutical composition comprising the pharmaceutically acceptable salt of the compound according to claim 20 ; and a pharmaceutically acceptable carrier.

30. A pharmaceutical composition comprising a compound according to claim 22 ; and a pharmaceutically acceptable carrier.

31. A pharmaceutical composition comprising the pharmaceutically acceptable salt of the compound according to claim 23 ; and a pharmaceutically acceptable carrier.

32. A pharmaceutical composition comprising a compound according to claim 25 ; and a pharmaceutically acceptable carrier.

33. A pharmaceutical composition comprising the pharmaceutically acceptable salt of the compound according to claim 26 ; and a pharmaceutically acceptable carrier.