# US 9,040,534 B2 · [1,2,4]triazolo[4,3-a]pyrazines as P2X7 modulators

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- Number: US 9,040,534 B2
- Document ID: US9040534B2
- Status: Granted
- Kind: B2
- Application number: 14/212,306
- Filed: 2014-03-14
- Published: 2014-09-18
- Granted: 2015-05-26
- Earliest claimed: 2013-03-14
- Assignees: Janssen Pharmaceutica NV
- Applicants: Janssen Pharmaceutica NV
- Inventors: Michael K. Ameriks; Jason C. Rech; Brad M. Savall
- Web page: https://patentgrep.com/patent/US9040534B2

## CPC

- C07D 487/04: Ortho-condensed systems
- A61K 31/4985: Pyrazines or piperazines ortho- or peri-condensed with heterocyclic ring systems
- A61K 31/501: not condensed and containing further heterocyclic rings
- A61K 31/506: not condensed and containing further heterocyclic rings
- A61P 1/00: Drugs for disorders of the alimentary tract or the digestive system
- A61P 1/04: for ulcers, gastritis or reflux esophagitis, e.g. antacids, inhibitors of acid secretion, mucosal protectants
- A61P 3/00: Drugs for disorders of the metabolism (of the blood or the extracellular fluid A61P7/00)
- A61P 3/10: for hyperglycaemia, e.g. antidiabetics
- A61P 7/00: Drugs for disorders of the blood or the extracellular fluid
- A61P 7/02: Antithrombotic agents; Anticoagulants; Platelet aggregation inhibitors
- A61P 7/12: Antidiuretics, e.g. drugs for diabetes insipidus (ADH A61P5/10)
- A61P 9/00: Drugs for disorders of the cardiovascular system
- A61P 9/10: for treating ischaemic or atherosclerotic diseases, e.g. antianginal drugs, coronary vasodilators, drugs for myocardial infarction, retinopathy, cerebrovascula insufficiency, renal arteriosclerosis
- A61P 9/12: Antihypertensives
- A61P 11/00: Drugs for disorders of the respiratory system
- A61P 11/02: Nasal agents, e.g. decongestants
- A61P 11/06: Antiasthmatics
- A61P 11/14: Antitussive agents
- A61P 13/02: of urine or of the urinary tract, e.g. urine acidifiers
- A61P 13/10: of the bladder
- A61P 13/12: of the kidneys
- A61P 15/00: Drugs for genital or sexual disorders (for disorders of sex hormones A61P5/24); Contraceptives
- A61P 17/00: Drugs for dermatological disorders
- A61P 17/06: Antipsoriatics
- A61P 19/00: Drugs for skeletal disorders
- A61P 19/02: for joint disorders, e.g. arthritis, arthrosis
- A61P 19/08: for bone diseases, e.g. rachitism, Paget's disease
- A61P 19/10: for osteoporosis
- A61P 21/02: Muscle relaxants, e.g. for tetanus or cramps
- A61P 25/00: Drugs for disorders of the nervous system
- A61P 25/04: Centrally acting analgesics, e.g. opioids
- A61P 25/06: Antimigraine agents
- A61P 25/08: Antiepileptics; Anticonvulsants
- A61P 25/14: for treating abnormal movements, e.g. chorea, dyskinesia
- A61P 25/18: Antipsychotics, i.e. neuroleptics; Drugs for mania or schizophrenia
- A61P 25/20: Hypnotics; Sedatives
- A61P 25/22: Anxiolytics
- A61P 25/24: Antidepressants
- A61P 25/28: for treating neurodegenerative disorders of the central nervous system, e.g. nootropic agents, cognition enhancers, drugs for treating Alzheimer's disease or other forms of dementia
- A61P 27/06: Antiglaucoma agents or miotics
- A61P 29/00: Non-central analgesic, antipyretic or antiinflammatory agents, e.g. antirheumatic agents; Non-steroidal antiinflammatory drugs [NSAID]
- A61P 29/02: without antiinflammatory effect
- A61P 31/04: Antibacterial agents
- A61P 31/06: for tuberculosis
- A61P 33/02: Antiprotozoals, e.g. for leishmaniasis, trichomoniasis, toxoplasmosis
- A61P 35/00: Antineoplastic agents
- A61P 37/02: Immunomodulators
- A61P 37/08: Antiallergic agents (antiasthmatic agents A61P11/06; ophthalmic antiallergics A61P27/14)
- A61P 43/00: Drugs for specific purposes, not provided for in groups A61P1/00-A61P41/00
- C07D 487/14: Ortho-condensed systems
- Y02A 50/30: Against vector-borne diseases, e.g. mosquito-borne, fly-borne, tick-borne or waterborne diseases whose impact is exacerbated by climate change
- C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08)
- A61K: PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES (devices or methods specially adapted for bringing pharmaceutical products into particular physical or administering forms A61J3/00; chemical aspects of, or use of materials for deodorisation of air, for disinfection or sterilisation, or for bandages, dressings, absorbent pads or surgical articles A61L; soap compositions C11D)
- A61P: SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
- Y02A: TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE

## Abstract

The present invention is directed to a compound of Formula (I) and to pharmaceutical compositions comprising compounds of Formula (I). Methods of making and using the compounds of Formula (I) are also within the scope of the invention.

## Claims

### Claim 1

A compound of Formula (I) wherein:
R2 is H, halo, SO2CH3, C1-3 alkyl, NO2, NH2, perhaloalkyl or perhaloalkoxy; or
two R2 substituents are taken together to form:
n is 0, 1, 2 or 3;
X is H or C1-C3 alkyl;
Y is H, C1-C3 alkyl or C3-C4 cycloalkyl;
R1 is selected from the group consisting of:
Ra, Rc and Rg are independently H or halo;
Rd is H or alkoxy;
Re is H, C1-C3 alkyl or halo;
Rb, Rf, Rh, Ri, Rj, Rk, Rl, Rm, Rn, Ro are independently H, C1-C3 alkyl or perhaloalkyl;
Rp is H or CO2C(CH3)3; and
pharmaceutically acceptable salts of compounds of Formula (I).

### Claim 2 (depends on 1)

The compound as in claim 1, wherein R2 is halo.

### Claim 3 (depends on 1)

The compound as in claim 1, wherein R2 is perfluoroalkyl.

### Claim 4 (depends on 1)

The compound as in claim 1, wherein R2 is halo and perfluoroalkyl.

### Claim 5 (depends on 1)

The compound as in claim 1, wherein n is 1 or 2.

### Claim 6 (depends on 1)

The compound as in claim 1, wherein n is 2.

### Claim 7 (depends on 1)

The compound as in claim 1, wherein at least one R2 substituent is in the ortho position and at least one R2 substituent is in the meta position.

### Claim 8 (depends on 1)

The compound as in claim 1, wherein n is 2, R2 is CF3 and R2 is Cl.

### Claim 9 (depends on 1)

The compound as in claim 1, wherein n is 2, R2 is Cl and is in the ortho position and R2 is CF3 and is in the meta position.

### Claim 10 (depends on 1)

The compound as in claim 1, wherein Y is CH3, CH2CH3, or cyclopropyl.

### Claim 11 (depends on 1)

The compound as in claim 1, wherein X is H.

### Claim 12 (depends on 1)

The compound as in claim 1 wherein R1 is selected from the group consisting of:

### Claim 13 (depends on 1)

The compound as in claim 1 wherein R1 is selected from the group consisting of:

### Claim 14 (depends on 1)

The compound as in claim 1 wherein Rg is 3H, Rh is H and R1 is

### Claim 15 (depends on 1)

The compound as in claim 1 wherein Rf is H and R1 is

### Claim 16 (depends on 1)

The compound as in claim 1 wherein Y is CH3, X is H, R2 is in the ortho position and is Cl, R2 is in the meta position and is CF3, Rf is H and R1 is

### Claim 17 (depends on 1)

The compound as in claim 1 wherein Y is CH3, X is H, R2 is in the ortho position and is Cl, R2 is in the meta position and is CF3, Rg is 3H, Rh is H and R1 is

### Claim 18

A compound selected from the group consisting of:
7-[2-Chloro-3-(trifluoromethyl)benzyl]-3-(4-fluorophenyl)-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
7-(2,3-Dichlorobenzyl)-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
7-[2-Chloro-3-(trifluoromethyl)benzyl]-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(±)7-{1-[2-Chloro-3-(trifluoromethyl)phenyl]ethyl}-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
7-(2,6-Dichlorobenzyl)-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
7-(2,3-Difluorobenzyl)-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
7-[4-Chloro-2-(methylsulfonyl)benzyl]-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
7-(2,3-Dichlorobenzyl)-3-pyridin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
7-[2-Chloro-3-(trifluoromethyl)benzyl]-3-pyridin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
7-[2-Methyl-3-(trifluoromethyl)benzyl]-3-pyridin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(±)-7-(2,3-Dichlorobenzyl)-6-methyl-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6R)-7-(2,3-Dichlorobenzyl)-6-methyl-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-(2,3-Dichlorobenzyl)-6-methyl-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(±)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-methyl-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6R)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-methyl-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-methyl-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-3-(4-fluorophenyl)-6-methyl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-methyl-3-pyridin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-methyl-3-(5-methylpyrazin-2-yl)-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-methyl-3-(1,3-oxazol-2-yl)-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-methyl-3-(1,3-oxazol-4-yl)-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-methyl-3-(1,3-oxazol-5-yl)-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-methyl-3-(1-methyl-1H-pyrazol-3-yl)-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-methyl-3-(1-methyl-1H-pyrazol-4-yl)-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-methyl-3-(1H-pyrazol-4-yl)-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-methyl-3-(5-methyl-1H-pyrazol-3-yl)-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-methyl-3-pyrimidin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-methyl-3-(1H-pyrazol-3-yl)-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-methyl-3-pyridin-3-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-3-(5-fluoropyridin-2-yl)-6-methyl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-methyl-3-(1,3-thiazol-2-yl)-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-methyl-3-(1,3-thiazol-4-yl)-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-methyl-3-pyrimidin-4-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-3-(5-fluoropyrimidin-2-yl)-6-methyl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-3-(4-methoxypyridin-2-yl)-6-methyl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-methyl-3-(2-methyl-1,3-thiazol-4-yl)-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-methyl-3-(1,3-thiazol-5-yl)-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-methyl-3-[2-(trifluoromethyl)-1,3-thiazol-4-yl]-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-3-(2,4-dimethyl-1,3-thiazol-5-yl)-6-methyl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-methyl-3-(4-methyl-1,3-thiazol-5-yl)-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-3-isoxazol-3-yl-6-methyl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-3-(5-Bromopyrimidin-2-yl)-7-[2-chloro-3-(trifluoromethyl)benzyl]-6-methyl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-3-(5-Tritiopyrimidin-2-yl)-7-[2-chloro-3-(trifluoromethyl)benzyl]-6-methyl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-methyl-3-pyridazin-3-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-3-(5-fluoropyridin-3-yl)-6-methyl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-methyl-3-(6-methyl pyridin-2-yl)-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-methyl-3-pyridin-4-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-methyl-3-(2-methyl pyridin-3-yl)-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-3-cyclobutyl-6-methyl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-3-cyclopropyl-6-methyl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-3-cyclohexyl-6-methyl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-3-(5-Chloropyridin-3-yl)-7-[2-chloro-3-(trifluoromethyl)benzyl]-6-methyl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-methyl-3-(tetrahydro-2H-pyran-4-yl)-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-chloro-3-(trifluoromethyl)benzyl]-6-methyl-3-[4-(trifluoromethyl)pyrimidin-2-yl]-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-methyl-3-[6-(trifluoromethyl)pyridin-2-yl]-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-3-(5-Chloropyridin-2-yl)-7-[2-chloro-3-(trifluoromethyl)benzyl]-6-methyl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-methyl-3-(5-methylpyridin-3-yl)-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-tert-Butyl3-{7-[2-chloro-3-(trifluoromethyl)benzyl]-6-methyl-8-oxo-5,6,7,8-tetrahydro[1,2,4]triazolo[4,3-a]pyrazin-3-yl}pyrrolidine-1-carboxylate;
(6S)-tert-Butyl3-{7-[2-chloro-3-(trifluoromethyl)benzyl]-6-methyl-8-oxo-5,6,7,8-tetrahydro[1,2,4]triazolo[4,3-a]pyrazin-3-yl}piperidine-1-carboxylate;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-methyl-3-piperidin-3-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(±)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-cyclopropyl-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6R*)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-cyclopropyl-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S*)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-cyclopropyl-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(±)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-cyclopropyl-3-pyrimidin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6R*)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-cyclopropyl-3-pyrimidin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S*)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-cyclopropyl-3-pyrimidin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(±)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-cyclopropyl-3-pyridin-3-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(±)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-cyclopropyl-3-(1H-pyrazol-3-yl)-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(±)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-cyclopropyl-3-(5-fluoropyridin-2-yl)-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(±)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-cyclopropyl-3-(5-fluoropyrimidin-2-yl)-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-ethyl-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-ethyl-3-pyrimidin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-ethyl-3-pyridin-3-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-ethyl-3-(1H-pyrazol-3-yl)-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-ethyl-3-(5-fluoropyrimidin-2-yl)-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-3-(trifluoromethyl)benzyl]-6-ethyl-3-(5-fluoropyridin-2-yl)-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-(2-Chloro-4-fluorobenzyl)-6-methyl-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-Benzyl-6-methyl-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-(2-Chlorobenzyl)-6-methyl-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[2-Chloro-4-(methylsulfonyl)benzyl]-6-methyl-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[4-Chloro-2-(methylsulfonyl)benzyl]-6-methyl-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-6-Methyl-3-pyrazin-2-yl-7-[2-(trifluoromethoxy)benzyl]-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-[(6-Chloro-1,3-benzodioxol-5-yl)methyl]-6-methyl-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-6-Methyl-7-[2-methyl-3-(trifluoromethyl)benzyl]-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-(2,6-Dichlorobenzyl)-6-methyl-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-(2,6-Dimethylbenzyl)-6-methyl-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-6-Methyl-3-pyrazin-2-yl-7-[3-(trifluoromethyl)benzyl]-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-6-Methyl-7-(2-nitrobenzyl)-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-(2-Chloro-5-nitrobenzyl)-6-methyl-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-7-(5-Amino-2-chlorobenzyl)-6-methyl-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-6-Methyl-7-(1-phenylethyl)-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-6-Methyl-7-[(1R/S)-1-phenylethyl]-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one;
(6S)-6-Methyl-7-[(1R*)-1-phenylethyl]-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one; and
(6S)-6-Methyl-7-[(1S*)-1-phenylethyl]-3-pyrazin-2-yl-6,7-dihydro[1,2,4]triazolo[4,3-a]pyrazin-8(5H)-one.

### Claim 19

A pharmaceutical composition comprising:
(a) an effective amount of at least one compound selected from compounds of Formula (I) wherein:
R2 is H, halo, SO2CH3, C1-3 alkyl, NO2, NH2, perhaloalkyl or perhaloalkoxy; or
two R2 substituents are taken together to form:
n is 0, 1, 2 or 3;
X is H or C1-C3 alkyl;
Y is H, C1-C3 alkyl or C3-C4 cycloalkyl;
R1 is selected from the group consisting of:
Ra, Rc and Rg are independently H or halo;
Rd is H or alkoxy;
Re is H, C1-C3 alkyl or halo;
Rb, Rf, Rh, Ri, Rj, Rk, Rl, Rm, Rn, Ro are independently H, C1-C3 alkyl or perhaloalkyl;
Rp is H or CO2C(CH3)3; and
pharmaceutically acceptable salts of compounds of Formula (I); and
(b) at least one pharmaceutically acceptable excipient.

### Claim 20

A method of modulating P2X7 receptor activity in a subject, comprising administering to a subject in need of such treatment an effective amount of at least one compound selected from compounds of Formula (I) wherein:
R2 is H, halo, SO2CH3, C1-3 alkyl, NO2, NH2, perhaloalkyl or perhaloalkoxy; or
two R2 substituents are taken together to form:
n is 0, 1, 2 or 3;
X is H or C1-C3 alkyl;
Y is H, C1-C3 alkyl or C3-C4 cycloalkyl;
R1 is selected from the group consisting of:
Ra, Rc and Rg are independently H or halo;
Rd is H or alkoxy;
Re is H, C1-C3 alkyl or halo;
Rb, Rf, Rh, Ri, Rj, Rk, Rl, Rm, Rn, Ro are independently H, C1-C3 alkyl or perhaloalkyl;
Rp is H or CO2C(CH3)3; and
pharmaceutically acceptable salts of compounds of Formula (I).