504-30-3

Basic information

• Product Name: 3(2H)-Pyridazinone
• Synonyms: Pyridazin-3(2H)-one;2,3-Dihydropyridazine-3-one;Pyridazine-3-ol;1H-pyridazin-6-one;1H-Pyridazine-6-one;2,3-dihydropyridazin-3-one;3-hydropyridazine;2H-Pyridazin-3-one/Pyridazin-3-ol
• CAS NO: 504-30-3
• Molecular Formula: C4H4N2O
• Molecular Weight: 96.09
• Product Categories: Pyridazine series;Building Blocks;Heterocyclic Building Blocks;Pyridazines
• Mol File: 504-30-3.mol
• Article Data: 20

Chemical Properties

• Melting Point: 98-104 °C
• Boiling Point: 101°C/1.5mmHg(lit.)
• Flash Point: 144.9 °C
• Appearance: /
• Density: 1.28 g/cm³
• Storage Temp.: Keep in dark place,Sealed in dry,Room Temperature
• Solubility: DMSO (Slightly), Methanol (Slightly)
• PKA: 11.47±0.20(Predicted)
• BRN: 106974
• CAS DataBase Reference: 3(2H)-Pyridazinone(CAS DataBase Reference)
• NIST Chemistry Reference: 3(2H)-Pyridazinone(504-30-3)
• EPA Substance Registry System: 3(2H)-Pyridazinone(504-30-3)

Safety Data

• Hazard Codes: Xi
• Statements: 36/37/38
• Safety Statements: 26-36/37
• WGK Germany: 3
• Hazardous Substances Data: 504-30-3(Hazardous Substances Data)

Usage

Uses

Pyridazin-3(2H)-one can be used for anti-inflammatory and analgesic drug discovery.

InChI:InChI=1/C4H4N2O/c7-4-2-1-3-5-6-4/h1-3H,(H,6,7)

Synthetic route

3-Phenyl-7aH-1-oxa-2,3a,4-triaza-indene (178047-61-5) → 2H-Pyridazin-3-one (504-30-3)

Conditions	Yield
With air In benzene Ambient temperature; Irradiation;	90%

mucochloric acid (57697-64-0) → 2H-Pyridazin-3-one (504-30-3)

Conditions	Yield
Stage #1: mucochloric acid With tert-butylhydrazine In water; toluene at 23℃; for 2.8h; Stage #2: With tetrabutylammomium bromide; titanium(IV) oxide In water; toluene at 20℃; for 4.6h; Temperature;	88.9%

N'-acryloyl-N-allyl-4-methylbenzenesulfonohydrazide (1173165-19-9) → 2H-Pyridazin-3-one (504-30-3)

Conditions	Yield
With Hoveyda-Grubbs catalyst second generation In dichloromethane at 40℃; for 36h; Sealed tube; Inert atmosphere;	87%

5-(1,2-diaza-1-t-butylbutadien-4-ylidene)-2,2-dimethyl-1,3-dioxan-4,6-dione (83297-14-7) → 2H-Pyridazin-3-one (504-30-3)

Conditions	Yield
at 750℃; under 0.01 - 0.1 Torr; for 1.5h;	63%

6-chloro-2H-pyridazin-3-one (19064-67-6) → 2H-Pyridazin-3-one (504-30-3)

Conditions	Yield
With palladium on activated charcoal; hydrogen; potassium carbonate In ethyl acetate under 1551.49 Torr; for 3h;	55%

piperidine (110-89-4) + diethyl ether (60-29-7) + epichlorohydrin (106-89-8) + 6-(3-allyl-4-hydroxy-phenyl)-4,5-dihydro-2H-pyridazin-3-one (56872-17-4) → 2H-Pyridazin-3-one (504-30-3) + 6-(3-allyl-4-oxiranylmethoxy-phenyl)-4,5-dihydro-2H-pyridazin-3-one (56872-18-5)

Conditions	Yield
With sodium hydroxide In dichloromethane	A 47% B n/a

1,2-diazine (289-80-5) + benzonitrile oxide (873-67-6) → 2H-Pyridazin-3-one (504-30-3) + 6a,9a,9b-trihydro-3,9-diphenylisoxazolo<4,5-d><1,2,4>oxadiazolo<4,5-b>pyridazine

Conditions	Yield
In benzene for 3h; Heating;	A 3% B 29%

1,2-diazine (289-80-5) → 2H-Pyridazin-3-one (504-30-3) + 6a,9a,9b-trihydro-3,9-diphenylisoxazolo<4,5-d><1,2,4>oxadiazolo<4,5-b>pyridazine

Conditions	Yield
With benzonitrile oxide In benzene for 3h; Heating;	A 3% B 29%

3-oxo-2,3,4,5-tetrahydropyridazine (61468-81-3) → 2H-Pyridazin-3-one (504-30-3)

Conditions	Yield
With chloroform; bromine

4,5-dichloro-2H-pyridazin-3-one (932-22-9) → 2H-Pyridazin-3-one (504-30-3)

Conditions	Yield
With sodium hydroxide; palladium on activated charcoal Hydrogenation;

4,5-dibromo-3(2H)pyridazinone (5788-58-9) → 2H-Pyridazin-3-one (504-30-3)

Conditions	Yield
With sodium hydroxide; palladium on activated charcoal Hydrogenation;

6-oxo-1,6-dihydro-pyridazine-4-carboxylic acid (867130-58-3) → 2H-Pyridazin-3-one (504-30-3)

Conditions	Yield
With copper

3-oxo-2,3-dihydro-pyridazine-4-carboxylic acid (54404-06-7) → 2H-Pyridazin-3-one (504-30-3)

6-oxo-1,6-dihydro-pyridazine-3,4-dicarboxylic acid (867130-51-6) → 2H-Pyridazin-3-one (504-30-3)

Conditions	Yield
With copper

3-(ethyloxy)pyridazine (62567-44-6) → 2H-Pyridazin-3-one (504-30-3)

Conditions	Yield
at 376.8℃; Rate constant; Thermodynamic data; further temperatures;

phosgene (75-44-5) + 5-[3-(cyclopentyloxy)-4-methoxyphenyl]-1-methyl-3-pyrazolidinone (145743-48-2) → 2H-Pyridazin-3-one (504-30-3) + 3-[3-(cyclopentyloxy)-4-methoxyphenyl]-2-methyl-5-oxo-N-(3-pyridinylmethyl)-1-pyrazolidine carboxamide (145743-63-1)

Conditions	Yield
With triethylamine In tetrahydrofuran; methanol; ethyl acetate; toluene

allyl bromide (106-95-6) + 6-(3-hydroxyphenyl)-4,5-dihydro-3(2H)-pyridazinone (39499-64-4) → 2H-Pyridazin-3-one (504-30-3) + 6-(3-allyloxy-phenyl)-4,5-dihydro-2H-pyridazin-3-one (56872-13-0)

Conditions	Yield
With potassium carbonate In acetone

propyl bromide (106-94-5) + 6-(4-hydroxyphenyl)-4,5-dihydro-3(2H)-pyridazinone (39560-33-3) → 2H-Pyridazin-3-one (504-30-3)

Conditions	Yield
In sodium hydroxide; ethanol

C11H12N2O3S → 2H-Pyridazin-3-one (504-30-3)

Conditions	Yield
With 1,8-diazabicyclo[5.4.0]undec-7-ene In tetrahydrofuran at 20℃;

2H-Pyridazin-3-one (504-30-3) + N,N-dimethyl-formamide dimethyl acetal (4637-24-5) → 2-methylpyridazin-3(2H)-one (22687-56-5)

Conditions	Yield
In N,N-dimethyl-formamide Heating;	96%

2H-Pyridazin-3-one (504-30-3) + 4-bromoethylbutanoate (2969-81-5) → ethyl 4-[pyridazin-3(2H)-one-2-yl]-butyrate (346407-39-4)

Conditions	Yield
With potassium carbonate In acetone for 24h; Heating;	95%

2H-Pyridazin-3-one (504-30-3) + 4-iodobenzonitrile (3058-39-7) → 4-(6-oxo-6H-pyridazin-1-yl)-benzonitrile

Conditions	Yield
With copper(II) 7-n-propyl-8-hydroxyquinolinate; potassium carbonate In N,N-dimethyl-formamide at 100℃; for 20h;	94%

2H-Pyridazin-3-one (504-30-3) + 6-Bromo-2-methyl-quinoline (877-42-9) → 2-(2-methyl-quinolin-6-yl)-2H-pyridazin-3-one

Conditions	Yield
With copper(II) 7-n-propyl-8-hydroxyquinolinate; potassium carbonate In N,N-dimethyl-formamide at 140℃; for 20h;	90%

2H-Pyridazin-3-one (504-30-3) + acrylonitrile (107-13-1) → 3-(3-oxo-2-pyridazinyl)propionitrile (73535-74-7)

Conditions	Yield
With potassium hydroxide; tetrabutylammomium bromide In benzene for 5h; Ambient temperature;	89%
With N-benzyl-trimethylammonium hydroxide In ethanol for 8h; Heating;

2H-Pyridazin-3-one (504-30-3) + iodobenzene (591-50-4) → 2-phenyl-2H-pyridazin-3-one (14135-63-8)

Conditions	Yield
With caesium carbonate; hydroxybenzaldoxime; copper(I) oxide In acetonitrile at 82℃; for 100h;	89%

2H-Pyridazin-3-one (504-30-3) + 1-{[(1S,2S)-2-(4-bromophenyl)cyclopropyl]methyl}-(2S)-2-methylpyrrolidine (1000305-04-3) → 2-[4-((1S,2S)-2-{[(2S)-2-methylpyrrolidin-1-yl]methyl}cyclopropyl)phenyl]pyridazin-3(2H)-one

Conditions	Yield
With pyridine; potassium carbonate; copper(l) iodide; N,N`-dimethylethylenediamine In ethyl acetate at 115℃; Inert atmosphere;	86%
With pyridine; copper(l) iodide; N,N`-dimethylethylenediamine at 135℃; for 16h;
With pyridine; copper(l) iodide; N,N`-dimethylethylenediamine at 135℃; for 16h; Inert atmosphere; Sealed tube;

2H-Pyridazin-3-one (504-30-3) + 1-bromo-4-methoxy-benzene (104-92-7) → 2-(4-methoxy-phenyl)-2H-pyridazin-3-one

Conditions	Yield
With copper(II) 7-n-propyl-8-hydroxyquinolinate; potassium carbonate In N,N-dimethyl-formamide at 140℃; for 20h;	85%

2H-Pyridazin-3-one (504-30-3) + dimethyl acetylenedicarboxylate (762-42-5) → dimethyl 2-(6-oxopyridazin-1(6H)-yl)fumarate (1274944-76-1)

Conditions	Yield
With triphenyl-arsane In acetone at -5℃; for 5.16667h; diastereospecific reaction;	85%
With pyridine In dichloromethane at 20℃; for 24h; stereoselective reaction;	80%
With triphenyl-arsane In methanol at 28℃; Catalytic behavior; Kinetics; Mechanism; Temperature; Reagent/catalyst; Concentration; diastereoselective reaction;

2H-Pyridazin-3-one (504-30-3) + 6-bromo-2-(3,3-dimethoxycyclobutyl)benzothiazole (1416049-94-9) → 2-(2-(3,3-dimethoxycyclobutyl)benzothiazol-6-yl)-pyridazin-3(2H)-one (1416049-95-0)

Conditions	Yield
With pyridine; potassium carbonate; copper(l) chloride; N,N`-dimethylethylenediamine at 100℃; for 16.5h; Solvent; Reagent/catalyst; Inert atmosphere;	84%

2H-Pyridazin-3-one (504-30-3) + ethyl acrylate (140-88-5) → ethyl 3-[pyridazin-3(2H)-one-2-yl]-propionate (73535-75-8)

Conditions	Yield
In ethanol	83%

bis(4-tert-butylphenyl)iodonium trifluoromethanesulfonate (84563-54-2) + 2H-Pyridazin-3-one (504-30-3) → 2-(4-(tert-butyl)phenyl)pyridazin-3(2H)-one

Conditions	Yield
With triethylamine; copper(l) chloride In toluene at 20℃; for 1h; Inert atmosphere;	82%

2H-Pyridazin-3-one (504-30-3) + ethyl (3aR,6aR)-1-(4'-bromo-1,1'-biphenyl-4-yl)hexahydropyrrolo[3,4-b]pyrrole-5(1H)-carboxylate (948846-68-2) → ethyl (3aR,6aR)-1-[4'-(6-oxopyridazin-1(6H)-yl)-1,1'-biphenyl-4-yl]hexahydropyrrolo[3,4-b]pyrrole-5(1H)-carboxylate (948846-69-3)

Conditions	Yield
With potassium carbonate; copper(l) iodide; 8-quinolinol In N,N-dimethyl-formamide at 17 - 140℃; for 18h;	81.9%
With copper(l) iodide; 8-quinolinol; potassium carbonate In N,N-dimethyl-formamide at 17 - 140℃; for 18h; Product distribution / selectivity;	81.9%

2H-Pyridazin-3-one (504-30-3) + 3-iodobenzonitrile (69113-59-3) → 3-(6-oxo-6H-pyridazin-1-yl)-benzonitrile

Conditions	Yield
With copper(II) 7-n-propyl-8-hydroxyquinolinate; potassium carbonate In N,N-dimethyl-formamide at 100℃; for 20h;	80%

2H-Pyridazin-3-one (504-30-3) + 3,5-dimethylphenyl iodide (22445-41-6) → 2-(3,5-dimethyl-phenyl)-2H-pyridazin-3-one

Conditions	Yield
With copper(II) 7-n-propyl-8-hydroxyquinolinate; potassium carbonate In N,N-dimethyl-formamide at 100℃; for 20h;	80%

2H-Pyridazin-3-one (504-30-3) + (6S,7R)-tert-butyl 7-(4-chloro-3-fluorophenyl)-6-((methylsulfonyloxy)methyl)-1,4-oxazepane-4-carboxylate (1372187-07-9) → (6S,7R)-tert-butyl 7-(4-chloro-3-fluorophenyl)-6-((6-oxopyridazin-1(6H)-yl)methyl)-1,4-oxazepane-4-carboxylate

Conditions	Yield
With potassium carbonate In N,N-dimethyl-formamide at 80℃; for 4h;	78%

2H-Pyridazin-3-one (504-30-3) + 2-phenyl-1,3,4-oxadiazole (825-56-9) → 3-(5-phenyl-1,3,4-oxadiazol-2-yl)pyridazine (1366397-77-4)

Conditions

Yield

Stage #1: 2H-Pyridazin-3-one With N-ethyl-N,N-diisopropylamine; bromo-tris(1-pyrrolidinyl)phosphonium hexafluorophosphate In 1,4-dioxane at 100℃; for 0.5h; Inert atmosphere; Sealed vessel; Microwave irradiation; Stage #2: 2-phenyl-1,3,4-oxadiazole With copper(l) iodide; palladium diacetate; potassium carbonate; triphenylphosphine In 1,4-dioxane; 2,4-dichlorophenoxyacetic acid dimethylamine at 120℃; for 0.666667h; Inert atmosphere; Microwave irradiation; Sealed vessel;

75%

2H-Pyridazin-3-one (504-30-3) + trans-6-bromo-2-{3-[(2R)-2-methylpyrrolidin-1-yl]cyclobutyl}-1,3-benzothiazole → trans-2-(2-{3-[(2R)-2-methylpyrrolidin-1-yl]cyclobutyl}-1,3-benzothiazol-6-yl)pyridazin-3(2H)-one

Conditions	Yield
With pyridine; potassium carbonate; copper Heating / reflux;	74%

2H-Pyridazin-3-one (504-30-3) → 3-chloropyridazine (1120-95-2)

Conditions	Yield
With trichlorophosphate at 60℃; for 1.5h;	73%
With trichlorophosphate	63%
Stage #1: 2H-Pyridazin-3-one With trichlorophosphate at 85℃; for 4.5h; Stage #2: With sodium hydroxide In water at 0℃; pH=> 10;	46%

2H-Pyridazin-3-one (504-30-3) + 1-bromo-butane (109-65-9) → 2-Butyl-2H-pyridazin-3-one (79235-20-4)

Conditions	Yield
With potassium hydroxide; tetrabutylammomium bromide In benzene for 5h; Ambient temperature;	73%

2H-Pyridazin-3-one (504-30-3) → 3,3'-bipyridazine (10198-96-6)

Conditions

Yield

Stage #1: 2H-Pyridazin-3-one With triethylamine; bromo-tris(1-pyrrolidinyl)phosphonium hexafluorophosphate In 1,4-dioxane at 100℃; for 0.5h; Inert atmosphere; Sealed vessel; Microwave irradiation; Stage #2: With copper(l) iodide; palladium diacetate; potassium carbonate; triphenylphosphine In 1,4-dioxane; 2,4-dichlorophenoxyacetic acid dimethylamine at 120℃; for 0.666667h; Inert atmosphere; Microwave irradiation; Sealed vessel;

71%

2H-Pyridazin-3-one (504-30-3) + benzoxazole (273-53-0) → 2-(pyridazin-3-yl)benzo[d]oxazole (1366397-81-0)

Conditions

Yield

Stage #1: 2H-Pyridazin-3-one With triethylamine; bromo-tris(1-pyrrolidinyl)phosphonium hexafluorophosphate In 1,4-dioxane at 100℃; for 0.5h; Inert atmosphere; Sealed vessel; Microwave irradiation; Stage #2: benzoxazole With copper(l) iodide; palladium diacetate; potassium carbonate; triphenylphosphine In 1,4-dioxane; 2,4-dichlorophenoxyacetic acid dimethylamine at 120℃; for 0.666667h; Inert atmosphere; Microwave irradiation; Sealed vessel;

71%

oxirane (75-21-8) + 2H-Pyridazin-3-one (504-30-3) → 2-(2-Hydroxyethyl)-3-pyridazone (74316-72-6)

Conditions	Yield
With sodium methylate In methanol; N,N-dimethyl-formamide at 90℃; for 4h;	70%

2H-Pyridazin-3-one (504-30-3) + 4-chlorobutyl bromide (6940-78-9) → 2-(4-chlorobutyl)-pyridazin-3(2H)-one

Conditions	Yield
With potassium carbonate In acetone Alkylation; Heating;	70%

2H-Pyridazin-3-one (504-30-3) + Ethyl 3-bromopropionate (539-74-2) → ethyl 3-[pyridazin-3(2H)-one-2-yl]-propionate (73535-75-8)

Conditions	Yield
With potassium carbonate In acetone for 24h; Heating;	70%

2H-Pyridazin-3-one (504-30-3) + 2-bromo-6-iodo-naphthalene (389806-32-0) → 2-(6-bromo-naphthalen-2-yl)-2H-pyridazin-3-one

Conditions	Yield
With copper(II) 7-n-propyl-8-hydroxyquinolinate; potassium carbonate In N,N-dimethyl-formamide at 100℃; for 20h;	70%

Upstream product

• 867130-51-6 6-oxo-1,6-dihydro-pyridazine-3,4-dicarboxylic acid 
• 19064-67-6 6-chloro-2H-pyridazin-3-one 
• 61468-81-3 3-oxo-2,3,4,5-tetrahydropyridazine 
• 54404-06-7 3-oxo-2,3-dihydro-pyridazine-4-carboxylic acid 
• 867130-58-3 6-oxo-1,6-dihydro-pyridazine-4-carboxylic acid 
• 932-22-9 4,5-dichloro-2H-pyridazin-3-one 
• 932-22-9 4,5-Dichloro-3-hydroxypyridazine 
• 57697-64-0 mucochloric acid 
• 1173165-19-9 N'-acryloyl-N-allyl-4-methylbenzenesulfonohydrazide 
• 106-94-5 propyl bromide 
• 39560-33-3 6-(4-hydroxyphenyl)-4,5-dihydro-3(2H)-pyridazinone 
• 106-95-6 allyl bromide 
• 39499-64-4 6-(3-hydroxyphenyl)-4,5-dihydro-3(2H)-pyridazinone 
• 110-89-4 piperidine 

Downstream Products

• 95209-84-0 2-(6-oxopyridazin-1(6H)-yl)acetic acid 
• 1677-80-1 3,4-dicholoropyridazine 
• 494777-67-2 2-benzylpyridazin-3(2H)-one 
• 35053-42-0 1-phenyl-3-(pyridazin-3-yl)urea 
• 88491-61-6 3-bromopyridazine 
• 28544-77-6 3-mercaptopyridazine 
• 1360077-50-4 2,3-dimethoxy-5-methyl-6-[10-(pyridazin-3-yloxy)-decyl]-[1,4]benzoquinone 
• 551920-26-4 1-(6-hydroxypyrazolo[1,5-b]pyridazin-3-yl)ethanone 
• 766-55-2 imidazo[1.2-b]pyridazine 
• 1366397-79-6 3-(5-p-tolyl-1,3,4-thiadiazol-2-yl)pyridazine 
• 10198-96-6 3,3'-bipyridazine 
• 1083299-24-4 2-[6-oxopyridazin-1(6H)-yl]propanoic acid 
• 1150209-54-3 C₃₀H₃₄N₆O₅S 

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