(1) a hydrogen atom, (2) C1-8 alkyl, (3) C1-8 alkoxy, (4) hydroxy, (5) halogen atom, (6) nitro, (7) NR²R³, (8) C2-8 acyl, (9) C1-8 alkoxy substituted by phenyl or (10) C2-8 acyl substituted by NR²R³,

R² and R³ are each independently

(1) hydrogen atom or (2) C1-8 alkyl,

X and Y are each independently

(1) C or (2) CH,

(1) single bond or (2) double bond

cyclohexane, cyclohexene, or cyclohexadiene,

D¹ is

(1) —NR⁶C(O)—, (2) —NR⁶C(S)—, (3) —NR⁶SO₂—, (4) —CH₂—NR⁶—, (5) —CH₂—O—, (6) —OC(O)—, (7) —CH₂—NR⁶C(O)—, (8) —NR⁶C(O)NR⁷—, (9) —NR⁶C(O)O—, (10) —NR⁶C(S)NR⁷—, (11) —NR⁶— or (12) —NR⁶C(═NR⁷)—,

R⁶ and R⁷ are each independently

(1) a hydrogen atom, (2) C1-8 alkyl, (3) phenyl or (4) C1-8 alkyl substituted by phenyl,

D² is

(1) C1-8 alkylene, (2) C2-8 alkenylene, (3) Cyc2, (4) —(C1-4 alkylene)-O—(C1-4 alkylene)-, (5) —(C1-4 alkylene)-S—(C1-4 alkylene)-, (6) —(C1-4 alkylene)-NR⁸—(C1-4 alkylene)-, (7) -(Cyc2)-(C1-8 alkylene)-, (8) —(C1-8 alkylene)-(Cyc2)- or (9) —(C1-4 alkylene)-(Cyc2)-(C1-4 alkylene)-,

R⁸ is

(1) a hydrogen atom, (2) C1-8 alkyl, (3) C1-8 alkoxycarbonyl, (4) phenyl or (5) C1-8 alkyl substituted by phenyl,

D³ is

(1) a hydrogen atom, (2) —NR⁹R¹⁰, (3) Cyc3, (4) —OR¹¹, (5) COOR¹², (6) CONR¹³R¹⁴, (7) cyano, (8) a halogen atom, (9) —C(═CR¹⁵)NR¹⁶R¹⁷ or (10) —NR¹⁸C(═NR¹⁹)NR²⁰R²¹,

R⁹ and R¹³ are each independently

(1) a hydrogen atom, (2) C1-8 alkyl, (3) C2-8 alkenyl, (4) C2-8 alkynyl, (5) Cyc3, (6) C1-8 alkoxy, (7) C2-8 alkenyloxy, (8) C2-8 alkynyloxy or (9) C1-8 alkyl substituted by Cyc3, C1-8 alkoxy, C1-8 alkylthio, cyano, hydroxy or 1 to 3 halogen atoms,

R¹⁰ and R¹⁴ are each independently

(1) a hydrogen atom, (2) C1-8 alkyl, (3) C2-8 alkenyl, (4) C2-8 alkynyl, (5) C1-8 alkoxycarbonyl, (6) C2-8 acyl, (7) C3-8 cycloalkyl, (8) C1-8 alkoxycarbonyl substituted by Cyc4 or 1 to 3 halogen atoms, or (9) C1-8 alkyl substituted by C1-8 alkoxy,

R¹¹ and R¹² are each independently

(1) a hydrogen atom or (2) C1-8 alkyl,

R¹⁵, R¹⁶, R¹⁷, R¹⁸, R¹⁹, R²⁰ and R²¹ are each independently

(1) a hydrogen atom, (2) C1-8 alkyl, (3) C1-8 alkoxycarbonyl, (4) phenyl or (5) C1-8 alkyl substituted by phenyl,

R⁴ is

(1) a hydrogen atom, (2) C1-8 alkyl, (3) C1-8 alkoxy, (4) hydroxy, (5) halogen atom, (6) nitro or (7) NR²²R²³,

R²² and R²³ are each independently

(1) a hydrogen atom or (2) C1-8 alkyl,

E¹ is

C1-4 alkylene,

E² is

(1) —C(O)NR²⁴—, (2) —NR²⁴C(O)—, (3) —NR²⁴—, (4) —C(O)O— or (5) —S—,

R²⁴ is

(1) a hydrogen atom, (2) C1-8 alkyl or (3) C1-8 alkyl substituted by phenyl,

E³ is

(1) bond or (2) C1-8 alkylene,

E⁴ is

(1) C1-8 alkyl, (2) C2-8 alkenyl, (3) C2-8 alkynyl,

(4) cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclononane, cyclodecane, cyclopropene, cyclobutene, cyclopentene, cyclohexene, cycloheptene, cyclooctene, cyclononene, cyclodecene, cyclopentadiene, cyclohexadiene, cycloheptadiene, cyclooctadiene, pentalene, azulene, perhydroazulene, perhydropentalene, indene, perhydroindene, indan, naphthalene, teterahydronaphthalene, perhydronaphthalene, pyrrole, imidazole, triazole, tetrazole, pyrazole, pyridine, pyrazine, pyrimidine, pyridazine, azepine, diazepine, furan, pyran, oxepine, thiophene, thiaine, thiepine, oxazole, isoxazole, thiazole, isothiazole, furazan, oxadiazole, oxazine, oxadiazine, oxazepine, oxadiazepine, thiadiazole, thiazine, thiadiazine, thiazepine, thiadiazepine, indole, isoindole, indolizine, benzofuran, isobenzoftiran, benzothiophene, isobenzothiophene, dithianaphthalene, indazole, quinoline, isoquinoline, quinolizine, purine, phthalazine, pteridine, naphthyridine, quinoxaline, quinazoline, cinnoline, benzoxazole, benzothiazole, benzimidazole, chromene, benzofurazan, benzothiadiazole, benzotriazole, aziridine, azetidine, pyrroline, pyrrolidine, imidazoline, imidazolidine, triazoline, triazolidine, tetrazoline, tetrazolidine, pyrazoline, pyrazolidine, dihydropyridine, tetrahydropyridine, piperidine, dihydropyrazine, tetrahydropyrazine, piperazine, dihydropyrimidine, tetrahydropyrimidine, perhydropyrimidine, dihydropyridazine, tetrahydropyridazine, perhydropyridazine, dihydroazepine, tetrahydroazepine, perhydroazepine, dihydrodiazepine, tetrahydrodiazepine, perhydrodiazepine, oxirane, oxetane, dihydrofuran, tetrahydrofuran, dihydropyran, tetrahydropyran, dihydrooxepine, tetrahydrooxepine, perhydrooxepine, thiirane, thietane, dihydrothiophene, tetrahydrothiophene, dihydrothiaine, tetrahydrothiaine, dihydrothiepine, tetrahydrothiepine, perhydrothiepine, dihydrooxazole, tetrahydrooxazole, dihydroisoxazole, tetrahydroisoxazole, dihydrothiazole, tetrahydrothiazole, dihydroisothiazole, tetrahydroisothiazole, dihydrofurazan, tetrahydrofurazan, dihydrooxadiazole, tetrahydrooxadiazole, dihydrooxazine, tetrahydrooxazine, dihydrooxadiazine, tetrahydrooxadiazine, dihydrooxazepine, tetrahydrooxazepine, perhydrooxazepine, dihydrooxadiazepine, tetrahydrooxadiazepine, perhydrooxadiazepine, dihydrothiadiazole, tetrahydrothiadiazole, dihydrothiazine, tetrahydrothiazine, dihydrothiadiazine, tetrahydrothiadiazine, dihydrothiazepine, tetrahydrothiazepine, perhydrothiazepine, dihydrothiadiazepine, tetrahydrothiadiazepine, perhydrothiadiazepine, morpholine, thiomorpholine, oxathiane, indoline, isoindoline, dihydrobenzofuran, perhydrobenzofiiran, dihydroisobenzofuran, perhydroisobenzofuran, dihydrobenzothiophene, perhydrobenzothiophene, dihydroisobenzothiophene, perhydroisobenzothiophene, dihydroindazole, perhydroindazole, dihydroquinoline, tetrahydroquinoline, perhydroquinoline, dihydroisoquinoline, tetrahydroisoquinoline, perhydroisoquinoline, dihydrophthalazine, tetrahydrophthalazine, perhydroplithalazine, dihydronaphthyridine, tetrahydronaphthyridine, perhydronaphthyridine, dihydroquinoxaline, tetrahydroquinoxaline, perhydroquinoxaline, dihydroquinazoline, tetrahydroquinazoline, perhydroquinazoline, dihydrocinnoline, tetrahydrocinnoline, perhydrocinnoline, benzoxathiane, dihydrobenzoxazine, dihydrobenzothiazine, pyrazinomorpholine, dihydrobenzoxazole, perhydrobenzoxazole, dihydrobenzothiazole, perhydrobenzothiazole, dihydrobenzimidazole, perhydrobenzimidazole, dioxolane, dioxane, dithiolane, dithiane, dioxaindan, benzodioxane, chroman, benzodithiolane or benzodithiane, which may be substituted by 1 to 3 substituents selected from (i) C1-8 alkyl, (ii) C2-8 alkenyl, (iii) C1-8 alkoxy, (iv) a halogen atom, (v) trihalomethyl, (vi) trihalomethoxy, (vii) C1-8 alkoxycarbonyl, (viii) oxo, (ix) C1-8 alkyl substituted by C1-8 alkoxy or phenyl, (x) hydroxy and (xi) NR²⁹R³⁰,

(5) NR²⁵R²⁶, (6) OR²⁷, (7) SR²⁷, (8) COOR²⁷, (9) C1-8 alkyl substituted by two of OR²⁵, (10) C1-8 alkyl substituted by 1 to 3 halogen atoms, (11) cyano or (12) C2-8 acyl,

R²⁵ is

(1) a hydrogen atom, (2) C1-8 alkyl, (3) C2-8 alkenyl, (4) C2-8 alkynyl, (5) Cyc5 or (6) C1-8 alkyl substituted by Cyc5 or OR²⁸,

R²⁶ is

(1) a hydrogen atom, (2) C1-8 alkyl, (3) C1-8 alkoxycarbonyl, (4) phenyl or (5) C1-8 alkyl substituted by phenyl,

R²⁷ is

(1) a hydrogen atom, (2) C1-8 alkyl, (3) Cyc5, or (4) C1-8 alkyl substituted by Cyc5,

R²⁸ is

(1) a hydrogen atom or (2) C1-8 alkyl,

G¹ is

C1-8 alkylene,

Cyc1 is

(1) cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclononane, cyclodecane, cyclopropene, cyclobutene, cyclopentene, cyclohexene, cycloheptene, cyclooctene, cyclononene, cyclodecene, cyclopentadiene, cyclohexadiene, cycloheptadiene, cyclooctadiene, benzene, pentalene, azulene, perhydroazulene, perhydropentalene, indene, perhydroindene, indan, naphthalene, teterahydronaphthalene or perhydronaphthalene, or

(2) pyrrole, imidazole, triazole, tetrazole, pyrazole, pyridine, pyrazine, pyrimidine, pyridazine, azepine, diazepine, furan, pyran, oxepine, thiophene, thiaine, thiepine, oxazole, isoxazole, thiazole, isothiazole, furazan, oxadiazole, oxazine, oxadiazine, oxazepine, oxadiazepine, thiadiazole, thiazine, thiadiazine, thiazepine, thiadiazepine, indole, isoindole, indolizine, benzofuran, isobenzofuran, benzothiophene, isobenzothiophene, dithianaphthalene, indazole, quinoline, isoquinoline, quinolizine, purine, phthalazine, pteridine, naphthyridine, quinoxaline, quinazoline, cinnoline, benzoxazole, benzothiazole, benzimidazole, chromene, benzofurazan, benzothiadiazole, benzotriazole, aziridine, azetidine, pyrroline, pyrrolidine, imidazoline, imidazolidine, triazoline, triazolidine, tetrazoline, tetrazolidine, pyrazoline, pyrazolidine, dihydropyridine, tetrahydropyridine, piperidine, dihydropyrazine, tetrahydropyrazine, piperazine, dihydropyrimidine, tetrahydropyrimidine, perhydropyrimidine, dihydropyridazine, tetrahydropyridazine, perhydropyridazine, dihydroazepine, tetrahydroazepine, perhydroazepine, dihydrodiazepine, tetrahydrodiazepine, perhydrodiazepine, oxirane, oxetane, dihydroftiran, tetrahydrofuran, dihydropyran, tetrahydropyran, dihydrooxepine, tetrahydrooxepine, perhydrooxepine, thiirane, thietane, dihydrothiophene, tetrahydrothiophene, dihydrothjaine, tetrahydrothiaine, dihydrothiepine, tetrahydrothiepine, perhydrothiepine, dihydrooxazole, tetrahydrooxazole, dihydroisoxazole, tetrahydroisoxazole, dihydrothiazole, tetrahydrothiazole, dihydroisothiazole, tetrahydroisothiazole, dihydrofurazan, tetrahydrofurazan, dihydrooxadiazole, tetrahydrooxadiazole, dihydrooxazine, tetrahydrooxazine, dihydrooxadiazine, tetrahydrooxadiazine, dihydrooxazepine, tetrahydrooxazepine, perhydrooxazepine, dihydrooxadiazepine, tetrahydrooxadiazepine, perhydrooxadiazepine, dihydrothiadiazole, tetrahydrothiadiazole, dihydrothiazine, tetrahydrothiazine, dihydrothiadiazine, tetrahydrothiadiazine, dihydrothiazepine, tetrahydrothiazepine, perhydrothiazepine, dihydrothiadiazepine, tetrahydrothiadiazepine, perhydrothiadiazepine, morpholine, thiomorpholine, oxathiane, indoline, isoindoline, dihydrobenzofuran, perhydrobenzofuran, dihydroisobenzofiiran, perhydroisobenzofuran, dihydrobenzothiophene, perhydrobenzothiophene, dihydroisobenzothiophene, perhydroisobenzothiophene, dihydroindazole, perhydroindazole, dihydroquinoline, tetrahydroquinoline, perhydroquinoline, dihydroisoquinoline, tetrahydroisoquinoline, perhydroisoquinoline, dihydrophthalazine, tetrahydrophthalazine, perhydrophthalazine, dihydronaphthyridine, tetrahydronaphthyridine, perhydronaphthyridine, dihydroquinoxaline, tetrahydroquinoxaline, perhydroquinoxaline, dihydroquinazoline, tetrahydroquinazoline, perhydroquinazoline, dihydrocinnoline, tetrahydrocinnoline, perhydrocinnoline, benzoxathiane, dihydrobenzoxazine, dihydrobenzothiazine, pyrazinomorpholine, dihydrobenzoxazole, perhydrobenzoxazole, dihydrobenzothiazole, perhydrobenzothiazole, dihydrobenzimidazole, perhydrobenzimidazole, dioxolane, dioxane, dithiolane, dithiane, dioxaindan, benzodioxane, chroman, benzodithiolane or benzodithiane,

G² is

(1) a hydrogen atom, (2) C1-8 alkyl, (3) C1-8 alkoxycarbonyl, (4) C2-8 acyl, (5) cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclononane, cyclodecane, cyclopropene, cyclobutene, cyclopentene, cyclohexene, cycloheptene, cyclooctene, cyclononene, cyclodecene, cyclopentadiene, cyclohexadiene, cycloheptadiene, cyclooctadiene, pentalene, azulene, perhydroazulene, perhydropentalene, indene, perhydroindene, indan, naphthalene, teterahydronaphthalene, perhydronaphthalene, pyrrole, imidazole, triazole, tetrazole, pyrazole, pyridine, pyrazine, pyrimidine, pyridazine, azepine, diazepine, furan, pyran, oxepine, thiophene, thiaine, thiepine, oxazole, isoxazole, thiazole, isothiazole, furazan, oxadiazole, oxazine, oxadiazine, oxazepine, oxadiazepine, thiadiazole, thiazine, thiadiazine, thiazepine, thiadiazepine, indole, isoindole, indolizine, benzofuran, isobenzofuran, benzothiophene, isobenzothiophene, dithianaphthalene, indazole, quinoline, isoquinoline, quinolizine, purine, phthalazine, pteridine, naphthyridine, quinoxaline, quinazoline, cinnoline, benzoxazole, benzothiazole, benzimidazole, chromene, benzofurazan, benzothiadiazole, benzotriazole, aziridine, azetidine, pyrroline, pyrrolidine, imidazoline, imidazolidine, triazoline, triazolidine, tetrazoline, tetrazolidine, pyrazoline, pyrazolidine, dihydropyridine, tetrahydropyridine, piperidine, dihydropyrazine, tetrahydropyrazine, piperazine, dihydropyrimidine, tetrahydropyrimidine, perhydropyrimidine, dihydropyridazine, tetrahydropyridazine, perhydropyridazine, dihydroazepine, tetrahydroazepine, perhydroazepine, dihydrodiazepine, tetrahydrodiazepine, perhydrodiazepine, oxirane, oxetane, dihydrofuran, tetrahydrofuran, dihydropyran, tetrahydropyran, dihydrooxepine, tetrahydrooxepine, perhydrooxepine, thiirane, thietane, dihydrothiophene, tetrahydrothiophene, dihydrothiaine, tetrahydrothiaine, dihydrothiepine, tetrahydrothiepine, perhydrothiepine, dihydrooxazole, tetrahydrooxazole, dihydroisoxazole, tetrahydroisoxazole, dihydrothiazole, tetrahydrothiazole, dihydroisothiazole, tetrahydroisothiazole, dihydrofurazan, tetrahydrofurazan, dihydrooxadiazole, tetrahydrooxadiazole, dihydrooxazine, tetrahydrooxazine, dihydrooxadiazine, tetrahydrooxadiazine, dihydrooxazepine, tetrahydrooxazepine, perhydrooxazepine, dihydrooxadiazepine, tetrahydrooxadiazepine, perhydrooxadiazepine, dihydrothiadiazole, tetrahydrothiadiazole, dihydrothiazine, tetrahydrothiazine, dihydrothiadiazine, tetrahydrothiadiazine, dihydrothiazepine, tetrahydrothiazepine, perhydrothiazepine, dihydrothiadiazepine, tetrahydrothiadiazepine, perhydrothiadiazepine, morpholine, thiomorpholine, oxathiane, indoline, isoindoline, dihydrobenzofuran, perhydrobenzofuran, dihydroisobenzofuran, perhydroisobenzofuran, dihydrobenzothiophene, perhydrobenzothiophene, dihydroisobenzothiophene, perhydroisobenzothiophene, dihydroindazole, perhydroindazole, dihydroquinoline, tetrahydroquinoline, perhydroquinoline, dihydroisoquinoline, tetrahydroisoquinoline, perhydroisoquinoline, dihydrophthalazine, tetrahydrophthalazine, perhydrophthalazine, dihydronaphthyridine, tetrahydronaphthyridine, perhydronaphthyridine, dihydroquinoxaline, tetrahydroquinoxaline, perhydroquinoxaline, dihydroquinazoline, tetrahydroquinazoline, perhydroquinazoline, dihydrocinnoline, tetrahydrocinnoline, perhydrocinnoline, benzoxathiane, dihydrobenzoxazine, dihydrobenzothiazine, pyrazinomorpholine, dihydrobenzoxazole, perhydrobenzoxazole, dihydrobenzothiazole, perhydrobenzothiazole, dihydrobenzimidazole, perhydrobenzimidazole, dioxolane, dioxane, dithiolane, dithiane, dioxaindan, benzodioxane, chroman, benzodithiolane or benzodithiane,

which may be substituted by 1 to 3 substituents selected from (i) C1-8 alkyl, (ii) C2-8 alkenyl, (iii) C1-8 alkoxy, (iv) halogen atom, (v) trihalomethyl, (vi) trihalomethoxy, (vii) C1-8 alkoxycarbonyl, (viii) oxo, (ix) C1-8 alkyl substituted by C1-8 alkoxy or phenyl, (x) hydroxy and (xi) NR²⁹R³⁰, (6) C1-8 alkyl or C2-8 alkenyl substituted by 1 to 2 substituents selected from Cyc6, hydroxy and C1-8 alkoxy, (7) C1-8 alkoxycarbonyl substituted by Cyc6, (8) —C(O)-Cyc6, (9) nitro, (10) NR⁴¹R⁴², (11) C1-8 alkoxy or (12) C1-8 alkyl substituted by NR⁴¹ R⁴²,

R⁴¹ and R⁴² are each independently

(1) a hydrogen atom or (2) C1-8 alkyl,

R⁵ is

(1) a hydrogen atom, (2) C1-8 alkyl, (3) C1-8 alkoxy, (4) hydroxy, (5) nitro, (6) NR²⁹R³⁰, (7) C1-C8 alkyl substituted by NR²⁹R³⁰, (8) NHSO₂OH, (9) amidino, (10) cyano, (11) halogen atom, (12) Cyc8 or (13) C1-8 alkyl substited by Cyc8,

R²⁹ and R³⁰ are each independently

(1) a hydrogen atom or (2) C1-8 alkyl,

Cyc2, Cyc3, Cyc4, Cyc5, Cyc6 and Cyc8 are each independently

(1) cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclononane, cyclodecane, cyclopropene, cyclobutene, cyclopentene, cyclohexene, cycloheptene, cyclooctene, cyclononene, cyclodecene, cyclopentadiene, cyclohexadiene, cycloheptadiene, cyclooctadiene, benzene, pentalene, azulene, perhydroazulene, perhydropentalene, indene, perhydroindene, indan, naphthalene, teterahydronaphthalene or perhydronaphthalene, or

(2) pyrrole, imidazole, triazole, tetrazole, pyrazole, pyridine, pyrazine, pyrimidine, pyridazine, azepine, diazepine, furan, pyran, oxepine, thiophene, thiaine, thiepine, oxazole, isoxazole, thiazole, isothiazole, furazan, oxadiazole, oxazine, oxadiazine, oxazepine, oxadiazepine, thiadiazole, thiazine, thiadiazine, thiazepine, thiadiazepine, indole, isoindole, indolizine, benzofuran, isobenzofuran, benzothiophene, isobenzothiophene, dithianaphthalene, indazole, quinoline, isoquinoline, quinolizine, purine, plithalazine, pteridine, naphthyridine, quinoxaline, quinazoline, cinnoline, benzoxazole, benzothiazole, benzimidazole, chromene, benzofurazan, benzothiadiazole, benzotriazole, aziridine, azetidine, pyrroline, pyrrolidine, imidazoline, imidazolidine, triazoline, triazolidine, tetrazoline, tetrazolidine, pyrazoline, pyrazolidine, dihydropyridine, tetrahydropyridine, piperidine, dihydropyrazine, tetrahydropyrazine, piperazine, dihydropyrimidine, tetrahydropyrimidine, perhydropyrimidine, dihydropyridazine, tetrahydropyridazine, perhydropyridazine, dihydroazepine, tetrahydroazepine, perhydroazepine, dihydrodiazepine, tetrahydrodiazepine, perhydrodiazepine, oxirane, oxetane, dihydrofuran, tetrahydrofuran, dihydropyran, tetrahydropyran, dihydrooxepine, tetrahydrooxepine, perhydrooxepine, thiirane, thietane, dihydrothiophene, tetrahydrothiophene, dihydrothiaine, tetrahydrothiaine, dihydrothiepine, tetrahydrothiepine, perhydrothiepine, dihydrooxazole, tetrahydrooxazole, dihydroisoxazole, tetrahydroisoxazole, dihydrothiazole, tetrahydrothiazole, dihydroisothiazole, tetrahydroisothiazole, dihydrofurazan, tetrahydrofurazan, dihydrooxadiazole, tetrahydrooxadiazole, dihydrooxazine, tetrahydrooxazine, dihydrooxadiazine, tetrahydrooxadiazine, dihydrooxazepine, tetrahydrooxazepine, perhydrooxazepine, dihydrooxadiazepine, tetrahydrooxadiazepine, perhydrooxadiazepine, dihydrothiadiazole, tetrahydrothiadiazole, dihydrothiazine, tetrahydrothiazine, dihydrothiadiazine, tetrahydrothiadiazine, dihydrothiazepine, tetrahydrothiazepine, perhydrothiazepine, dihydrothiadiazepine, tetrahydrothiadiazepine, perhydrothiadiazepine, morpholine, thiomorpholine, oxathiane, indoline, isoindoline, dihydrobenzofuran, perhydrobenzoffiran, dihydroisobenzofuran, perhydroisobenzofiiran, dihydrobenzothiophene, perhydrobenzothiophene, dihydroisobenzothiophene, perhydroisobenzothiophene, dihydroindazole, perhydroindazole, dihydroquinoline, tetrahydroquinoline, perhydroquinoline, dihydroisoquinoline, tetrahydroisoquinoline, perhydroisoquinoline, dihydrophthalazine, tetrahydrophthalazine, perhydrophthalazine, dihydronaphthyridine, tetrahydronaphthyridine, perhydronaplithyridine, dihydroquinoxaline, tetrahydroquinoxaline, perhydroquinoxaline, dihydroquinazoline, tetrahydroquinazoline, perhydroquinazoline, dihydrocinnoline, tetrahydrocinnoline, perhydrocinnoline, benzoxathiane, dihydrobenzoxazine, dihydrobenzothiazine, pyrazinomorpholine, dihydrobenzoxazole, perhydrobeuzoxazole, dihydrobenzothiazole, perhydrobenzothiazole, dihydrobenzimidazole, perhydrobenzimidazole, dioxolane, dioxane, dithiolane, dithiane, dioxaindan, benzodioxane, chroman, benzodithiolane or benzodithiane,

Cyc7 is

(1) cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclononane, cyclodecane, cyclopropene, cyclobutene, cyclopentene, cyclohexene, cycloheptene, cyclooctene, cyclononene, cyclodecene, cyclopentadiene, cyclohexadiene, cycloheptadiene, cyclooctadiene, pentalene, azulene, perhydroazulene, perhydropentalene, indene, perhydroindene, indan, naphthalene, teterahydronaphthalene or perhydronaphthalene, or

(2) pyrrole, imidazole, triazole, tetrazole, pyrazole, pyridine, pyrazine, pyrimidine, pyridazine, azepine, diazepine, furan, pyran, oxepine, thiophene, thiaine, thiepine, oxazole, isoxazole, thiazole, isothiazole, flirazan, oxadiazole, oxazine, oxadiazine, oxazepine, oxadiazepine, thiadiazole, thiazine, thiadiazine, thiazepine, thiadiazepine, indole, isoindole, indolizine, benzofuran, isobenzofuran, benzothiophene, isobenzothiophene, dithianaphthalene, indazole, quinoline, isoquinoline, quinolizine, purine, phthalazine, pteridine, naphthyridine, quinoxaline, quinazoline, cinnoline, benzoxazole, benzothiazole, benzimidazole, chromene, benzofurazan, benzothiadiazole, benzotriazole, aziridine, azetidine, pyrroline, pyrrolidine, imidazoline, imidazolidine, triazoline, triazolidine, tetrazoline, tetrazolidine, pyrazoline, pyrazolidine, dihydropyridine, tetrahydropyridine, piperidine, dihydropyrazine, tetrahydropyrazine, piperazine, dihydropyrimidine, tetrahydropyrimidine, perhydropyrimidine, dihydropyridazine, tetrahydropyridazine, perhydropyridazine, dihydroazepine, tetrahydroazepine, perhydroazepine, dihydrodiazepine, tetrahydrodiazepine, perhydrodiazepine, oxirane, oxetane, dihydrofuran, tetrahydrofuran, dihydropyran, tetrahydropyran, dihydrooxepine, tetrahydrooxepine, perhydrooxepine, thuirane, thietane, dihydrothiophene, tetrahydrothiophene, dihydrothiaine, tetrahydrothiaine, dihydrothiepine, tetrahydrothiepine, perhydrothiepine, dihydrooxazole, tetrahydrooxazole, dihydroisoxazole, tetrahydroisoxazole, dihydrothiazole, tetrahydrothiazole, dihydroisothiazole, tetrahydroisothiazole, dihydrofurazan, tetrahydrofurazan, dihydrooxadiazole, tetrahydrooxadiazole, dihydrooxazine, tetrahydrooxazine, dihydrooxadiazine, tetrahydrooxadiazine, dihydrooxazepine, tetrahydrooxazepine, perhydrooxazepine, dihydrooxadiazepine, tetrahydrooxadiazepine, perhydrooxadiazepine, dihydrothiadiazole, tetrahydrothiadiazole, dihydrothiazine, tetrahydrothiazine, dihydrothiadiazine, tetrahydrothiadiazine, dihydrothiazepine, tetrahydrothiazepine, perhydrothiazepine, dihydrothiadiazepine, tetrahydrothiadiazepine, perhydrothiadiazepine, morpholine, thiomorpholine, oxathiane, indoline, isoindoline, dihydrobenzofuran, perhydrobenzofuran, dihydroisobenzofuran, perhydroisobenzofuran, dihydrobenzothiophene, perhydrobenzothiophene, dihydroisobenzothiophene, perhydroisobenzothiophene, dihydroindazole, perhydroindazole, dihydroquinoline, tetrahydroquinoline, perhydroquinoline, dihydroisoquinoline, tetrahydroisoquinoline, perhydroisoquinoline, dihydrophthalazine, tetrahydrophthalazine, perhydrophthalazine, dihydronaphthyridine, tetrahydronaphthyridine, perhydronaphthyridine, dihydroquinoxaline, tetrahydroquinoxaline, perhydroquinoxaline, dihydroquinazoline, tetrahydroquinazoline, perhydroquinazoline, dihydrocinnoline, tetrahydrocinnoline, perhydrocinnoline, benzoxathiane, dihydrobenzoxazine, dihydrobenzothiazine, pyrazinomorpholine, dihydrobenzoxazole, perhydrobenzoxazole, dihydrobenzothiazole, perhydrobenzothiazole, dihydrobenzimidazole, perhydrobenzimidazole, dioxolane, dioxane, dithiolane, dithiane, dioxaindan, benzodioxane, chroman, benzodithiolane or benzodithiane,

Cyc2, Cyc3, Cyc4, Cyc5, Cyc6 and Cyc8 are optionally substituted by 1 to 3 substituents selected from (1) C1-8 alkyl, (2) C2-8 alkenyl, (3) C1-8 alkoxy, (4) halogen atom, (5) trihalomethyl, (6) trihalomethoxy, (7) C1-8 alkoxycarbonyl, (8) oxo, (9) C1-8 alkyl substituted by C1-8 alkoxy or phenyl, (10) hydroxy and (11) NR²⁹R³⁰;

m and n are each independently 1 or 2,

wherein

(i) when A is A¹ or A², then

(ii) when A is A⁴ and

R⁵ is not

hydroxy or C1-8 alkoxy,

(iii) when A is A⁵, then

(iv) following compounds of (1) to (11) are excepted;

(1) 4-(3-chloro-4-methoxyphenyl)-4a,5,8,8a-tetrahydrophthalazin-1(2H)-one,

(2) 4-(3,4-dimethoxyphenyl)-5,6,7,8-tetrahydrophthalazin-1(2H)-one,

(3) 4-phenyl-6,7,8,8a-tetrahydropyrrolo[1,2-d][1,2,4]triazin-1(2H)-one,

(4) 4-phenyl-5,6,7,8-tetrahydrophthalazin-1(2H)-one,

(5) 4-(4-methylphenyl)-5,6,7,8-tetrahydrophthalazin-1(2H)-one,

(6) 4-(4-fluorophenyl)-5,6,7,8-tetrahydrophthalazin-1(2H)-one,

(7) 4-(4-chlorophenyl)-5,6,7,8-tetrahydrophthalazin-1(2H)-one,

(8) 4-(4-bromophenyl)-5,6,7,8-tetrahydrophthalazin-1(2H)-one,

(9) 4-(pyridin-4-ylmethyl)-5,6,7,8-tetrahydrophthalazin-1(2H)-one,

(10) 4-t-butoxycarbonylmethyl-5,6,7,8-tetrahydrophthalazin-1(2H)-one,

(11) 4-ethoxycarbonylmethyl-5,6,7,8-tetrahydrophthalazin-1(2H)-one,