626-03-9

Basic information

• Product Name: 2,4-Dihydroxypyridine
• Synonyms: 4-hydroxy-2(1h)-pyridon;3-DEAZAURACIL;4-HYDROXY-2-PYRIDONE;2,4-PYRIDINEDIOL;2(1H)-PYRIDINONE, 4-HYDROXY-;TIMTEC-BB SBB004331;2,4-Dihydroxypyridine,97%;3-Deazauracil, 4-Hydroxy-2-pyridone, 2,4-PYridinediol
• CAS NO: 626-03-9
• Molecular Formula: C₅H₅NO₂
• Molecular Weight: 111.1
• EINECS: 210-924-8
• Product Categories: Pyridines;Pyridine;Pyridines derivates;Aromatics Compounds;Aromatics;Bases & Related Reagents;Nucleotides;Building Blocks;C5;Chemical Synthesis;Heterocyclic Building Blocks;Heterocycle-Pyridine series;Pyridine Series
• Mol File: 626-03-9.mol
• Article Data: 4

Chemical Properties

• Melting Point: 272-276 °C(lit.)
• Boiling Point: 208.19°C (rough estimate)
• Flash Point: 117.6 °C
• Appearance: light yellow/powder
• Density: 1.3113 (rough estimate)
• Vapor Pressure: 0.00192mmHg at 25°C
• Refractive Index: 1.4260 (estimate)
• Storage Temp.: Inert atmosphere,Room Temperature
• Solubility: DMSO, Methanol
• PKA: pK1:1.37(+1);pK2:6.45(0);pK3:13(+1) (20°C)
• Water Solubility: 6.211g/L(20 oC)
• BRN: 108533
• CAS DataBase Reference: 2,4-Dihydroxypyridine(CAS DataBase Reference)
• NIST Chemistry Reference: 2,4-Dihydroxypyridine(626-03-9)
• EPA Substance Registry System: 2,4-Dihydroxypyridine(626-03-9)

Safety Data

• Hazard Codes: Xi
• Statements: 36/37/38
• Safety Statements: 26-36-37/39
• WGK Germany: 3
• RTECS: UV1146800
• HazardClass: IRRITANT
• Hazardous Substances Data: 626-03-9(Hazardous Substances Data)

Usage

Chemical Properties

white to yellow-beige crystals or cryst. powder

Uses

2,4-Dihydroxypyridine (3-deazauracil) was used in the synthesis of diazaphenoxathiin skeleton.

General Description

2,4-Dihydroxypyridine (3-deazauracil) is a potent inhibitor of dihydrouracil dehydrogenase.

InChI:InChI=1/C5H4N2O4/c8-3-1-2-6-5(9)4(3)7(10)11/h1-2H,(H2,6,8,9)

Synthetic route

2,4-dimethoxypyridine (18677-43-5) → 3-deazauracil (626-03-9)

Conditions	Yield
With hexamethyldisilathiane; sodium methylate In various solvent(s) at 180℃; for 24h;	75%

pyridin-4-ol (626-64-2) → 3-deazauracil (626-03-9)

Conditions	Yield
With sodium hydroxide at 290 - 310℃;

2,4-dihydroxy-nicotinic acid → 3-deazauracil (626-03-9)

Conditions	Yield
With hydrogenchloride

4.6-dioxy-pyridine-carboxylic acid-(3)ethyl ester → 3-deazauracil (626-03-9)

Conditions	Yield
With hydrogenchloride at 190 - 200℃;

4.6-dioxy-pyridine-carboxylic acid-(3) → 3-deazauracil (626-03-9)

Conditions	Yield
With hydrogenchloride at 190 - 200℃;

2,4-dihydroxy-nicotinonitrile (5657-64-7) → 3-deazauracil (626-03-9)

Conditions	Yield
Multi-step reaction with 2 steps 1: H2SO4 / Behandeln des Reaktionsgemisches mit wss. NaNO2 2: concentrated aqueous hydrochloric acid View Scheme

6-chloro-2,4-dihydroxy-nicotinonitrile (19867-18-6) → 3-deazauracil (626-03-9)

Conditions	Yield
Multi-step reaction with 3 steps 1: zinc-powder; aqueous H2SO4 2: H2SO4 / Behandeln des Reaktionsgemisches mit wss. NaNO2 3: concentrated aqueous hydrochloric acid View Scheme

3-deazauracil (626-03-9) → 2,4-dihydroxy-3-nitropyridine (89282-12-2)

Conditions	Yield
With sulfuric acid; nitric acid at 0℃; Industrial scale;	98%
With sulfuric acid; nitric acid at 0℃; for 0.75h;	96%
With nitric acid at 90℃; for 3h;	92%

3-deazauracil (626-03-9) → 3-bromo-2,4-dihydroxypyridine (96245-97-5)

Conditions	Yield
With hydrogen bromide; bromine; acetic acid In water at 0℃; for 0.5h;	96%
With hydrogen bromide; bromine In acetic acid	95%
With hydrogen bromide; bromine; acetic acid

3-deazauracil (626-03-9) → 2,4-dibromopyridine (58530-53-3) + 2,3,4-tribromopyridine (2402-91-7)

Conditions	Yield
With phosphorus(V) oxybromide at 125℃; for 4.5h;	A 90% B 9%
With phosphorus(V) oxybromide at 125℃; for 4.5h;	A 85% B 12%

3-deazauracil (626-03-9) → 4-hydroxy-3-nitro-2(1H)-pyridone (89282-12-2)

Conditions	Yield
With nitric acid at 80℃; for 0.25 - 0.333333h;	90%
With nitric acid	85%

3-deazauracil (626-03-9) → 4-hydrazinylpyridin-2(1H)-one (106689-41-2)

Conditions	Yield
With 2-methoxy-ethanol; hydrazine hydrate In water at 20℃; for 24h;	88.3%
With hydrazine In 2-methoxy-ethanol for 24h; Heating / reflux;	88.3%

3-deazauracil (626-03-9) + 4-methyl-benzaldehyde (104-87-0) → 3-(4-methylbenzyl)pyridine-2,4-diol

Conditions	Yield
With pyridine; diethyl 2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate at 100℃; for 4h; Knoevenagel Condensation;	84%

3-deazauracil (626-03-9) + 5-bromoveratralaldehyde (6948-30-7) + malononitrile (109-77-3) → C17H14BrN3O4 (1375353-76-6)

Conditions	Yield
1,4-diaza-bicyclo[2.2.2]octane In ethanol at 80℃; for 18h;	82.7%
With 1,4-diaza-bicyclo[2.2.2]octane In ethanol at 20 - 80℃; for 18h;	82.7%

3-deazauracil (626-03-9) + 1,3,5-tri-O-acetyl-2-deoxyribose (4594-52-9, 96291-74-6, 96291-75-7) → (3-acetoxy-5-(4-hydroxy-2-oxo-1-pyridyl)tetrahydrofuran-2-yl)methyl acetate

Conditions	Yield
Stage #1: 3-deazauracil With N,O-bis-(trimethylsilyl)-acetamide In acetonitrile at 20℃; for 0.666667h; Stage #2: 1,3,5-tri-O-acetyl-2-deoxyribose With tin(IV) chloride In acetonitrile at 20℃; for 15h;	82%

3-deazauracil (626-03-9) + 3-propoxy-benzoyl chloride (83230-74-4) → 3-Propoxy-benzoic acid 2-oxo-1,2-dihydro-pyridin-4-yl ester

Conditions	Yield
With pyridine for 4h; Ambient temperature;	81%

3-deazauracil (626-03-9) + 3,3-dimethyl acrylaldehyde (107-86-8) → 2,2-dimethyl-2,6-dihydro-5H-pyrano[3,2-c]pyridin-5-one (58134-10-4)

Conditions	Yield
With pyridine; magnesium sulfate Reflux;	80%
In water at 80℃; for 15h;	55%
With magnesium sulfate In pyridine

3-deazauracil (626-03-9) + Dimethyl itaconate (617-52-7) → dimethyl 2-((4-hydroxy-2-oxo-1-pyridyl)methyl)butanedioate

Conditions	Yield
With 1,8-diazabicyclo[5.4.0]undec-7-ene In N,N-dimethyl-formamide at 20℃; for 24h;	79%

3-deazauracil (626-03-9) + trifluoromethylsulfonic anhydride (358-23-6) → trifluoro-methanesulfonic acid 4-trifluoromethanesulfonyloxy-pyridin-2-yl ester

Conditions	Yield
With triethylamine In dichloromethane at 20℃; for 12h;	77%

3-deazauracil (626-03-9) + diethyl (N,N-diethylaminomethylene)malonate (80467-82-9) → 3-ethoxycarbonyl-5-hydroxy-6-azacoumarin

Conditions	Yield
With acetic acid at 20℃; for 18h; Pechmann condensation; Reflux;	75%

3-deazauracil (626-03-9) → 3,5-dibromo-2,4-dihydroxypyridine (80791-78-2)

Conditions	Yield
With bromine In hydrogen bromide at 20℃; for 1h;	72%
With hydrogen bromide; bromine In water at 0 - 20℃; for 1h; Inert atmosphere;	71%
With hydrogen bromide; bromine In water at 20℃; for 1h;	56%
With hydrogen bromide; bromine; acetic acid
With hydrogen bromide; bromine

3-deazauracil (626-03-9) → 2,3,4-tribromopyridine (2402-91-7)

Conditions	Yield
With phosphorus(V) oxybromide	70%
Multi-step reaction with 2 steps 1: concentrated aqueous hydrobromic acid; acetic acid; bromine 2: phosphoryl bromide / 130 °C View Scheme

3-deazauracil (626-03-9) → benzoic acid 4-(2,4-dichloro-benzyloxy)-5-(2,4-dichloro-benzyloxymethyl)-2-(4-hydroxy-2-oxo-2H-pyridin-1-yl)-3-methyl-tetrahydro-furan-3-yl ester

Conditions	Yield
Stage #1: 3-deazauracil With N,O-bis-(trimethylsilyl)-acetamide In acetonitrile at 90℃; for 0.75h; Stage #2: With trimethylsilyl trifluoromethanesulfonate In acetonitrile at 90℃; for 3.5h;	70%

3-deazauracil (626-03-9) + (E)-4-methyl-N-(quinolin-8-yl)hexa-3,5-dienamide → 3-(5-hydroxy-2-methyl-3,4-dihydro-2H-pyrano[2,3-b]pyridin-2-yl)-N-(quinolin-8-yl)propanamide

Conditions	Yield
With palladium diacetate; 4-methoxybenzoic acid In acetonitrile at 120℃; for 4h; regioselective reaction;	70%

3-deazauracil (626-03-9) + o-chlorobenzoyl chloride (609-65-4) → 2-Chloro-benzoic acid 2-oxo-1,2-dihydro-pyridin-4-yl ester

Conditions	Yield
With pyridine for 4h; Ambient temperature;	68%

3-deazauracil (626-03-9) + benzyl bromide (100-39-0) → 1-benzyl-4-benzyloxypyridin-2(1H)-one (108379-95-9)

Conditions	Yield
With potassium carbonate In N,N-dimethyl-formamide at 20℃; for 24h;	67%

3-deazauracil (626-03-9) + (5-(trifluoromethyl)pyridin-2-yl)methyl methanesulfonate → 4-{[(5-trifluoromethyl-2-pyridinyl)methyl]oxy}-2(1H)-pyridinone (1184949-45-8)

Conditions	Yield
With potassium carbonate In N,N-dimethyl-formamide at 80℃; for 6h;	63.6%

3-deazauracil (626-03-9) + (R)-Citronellal (2385-77-5) → 6,6,9-trimethyl-6a,7,8,9,10,10a-hexahydro-6H-isochromeno[3,4-b]pyridin-1-ol (1196672-52-2)

Conditions	Yield
With piperidine; pyridine In ethanol at 130℃; for 1h; Microwave irradiation;	63%

3-deazauracil (626-03-9) + 4-methoxyphenylboronic acid (5720-07-0) + phenylboronic acid (98-80-6) → 4-(4-methoxyphenyl)-2-phenylpyridine (1350737-69-7)

Conditions

Yield

Stage #1: 3-deazauracil With potassium carbonate; bromo-tris(1-pyrrolidinyl)phosphonium hexafluorophosphate In 1,4-dioxane at 100℃; for 3h; Inert atmosphere; Stage #2: 4-methoxyphenylboronic acid With (1,1'-bis(diphenylphosphino)ferrocene)palladium(II) dichloride In 1,4-dioxane; water at 100℃; for 4h; Suzuki-Miyaura coupling; Inert atmosphere; Stage #3: phenylboronic acid With 1,3-bis[(diphenylphosphino)propane]dichloronickel(II) In 1,4-dioxane; water at 100℃; for 20h; Suzuki-Miyaura coupling; Inert atmosphere; regioselective reaction;

63%

3-deazauracil (626-03-9) + acetyl chloride (75-36-5) → 4-acetoxy-2-pyridone (91615-39-3)

Conditions	Yield
With pyridine for 4h; Ambient temperature;	60%

3-deazauracil (626-03-9) + 3,4,5-trifluorobenzaldehyde → C17H11F3N2O4 (1233097-81-8)

Conditions	Yield
In ethanol at 90℃; for 24h;	59%

3-deazauracil (626-03-9) + 4-chlorophenylhydrazine hydrochloride (1073-70-7) → 8-chloro-2,5-dihydro-1H-pyrido[4,3-b]indol-1-one (1338377-65-3)

Conditions	Yield
Stage #1: 4-chlorophenylhydrazine hydrochloride With sodium hydroxide In ethanol; water Stage #2: 3-deazauracil In diphenylether at 190 - 300℃;	54%

3-deazauracil (626-03-9) + ethyl (2E)-3-dimethylamino-2-(1H-indol-3-yl)propenoate (714274-03-0) → 3-(1H-indol-3-yl)-2H-pyrano[3,2-c]pyridin-2,5(6H)-dione

Conditions	Yield
With acetic acid for 7h; Heating;	52%

3-deazauracil (626-03-9) + m-Chlorobenzoyl chloride (618-46-2) → C19H11Cl2NO4

Conditions	Yield
With pyridine for 2h; Ambient temperature;	50%

3-deazauracil (626-03-9) + benzylamine (100-46-9) → 4-(benzylamino)pyridin-2-ol

Conditions	Yield
at 170℃; for 3h;	50%

3-deazauracil (626-03-9) + isopropyl bromide (75-26-3) → 4-isopropoxypyridin-2-ol + 2-isopropoxypyridin-4-ol

Conditions	Yield
With potassium carbonate In N,N-dimethyl-formamide at 65℃; for 16h; Inert atmosphere;	A 48% B 13%

Upstream product

• 98645-42-2 2-bromo-4-methoxypyridine-3-carbonitrile 
• 53937-02-3 4-(benzyloxy)pyridin-2(1H)-one 
• 95689-38-6 1,1-dicyano-4-(N,N-dimethylamino)-2-methoxy-1,3-butadiene 
• 19867-18-6 6-chloro-2,4-dihydroxy-nicotinonitrile 
• 18677-43-5 2,4-dimethoxypyridine 
• 626-64-2 pyridin-4-ol 
• 5657-64-7 2,4-dihydroxy-nicotinonitrile 

Downstream Products

• 26452-80-2 2,4-dichloropyridine 
• 58530-53-3 2,4-dibromopyridine 
• 103792-81-0 3-chloro-pyridine-2,4-diol 
• 96245-97-5 3-bromo-2,4-dihydroxypyridine 
• 80791-78-2 3,5-dibromo-2,4-dihydroxypyridine 
• 89282-12-2 2,4-dihydroxy-3-nitropyridine 
• 40982-58-9 2,4-bis(trimethylsilyloxy)pyridine 
• 74990-54-8 4-anilino-2-oxo-1,2-dihydropyridine 
• 41759-19-7 4-methoxy-1-methyl-2-pyridone 
• 223718-54-5 3-(benzyloxycarbonyl)amino-5,6-dihydro-2H-pyrano<3,2-c>pyridine-2,5-dione 
• 2402-91-7 2,3,4-tribromopyridine 
• 586373-38-8 4-[(4-fluorobenzyl)oxy]pyridine-2(1H)-one 
• 128822-48-0 3-chloro-4-hydroxy-1-(2,3,5-tri-O-benzoyl-β-D-ribofuranosyl)-2(1H)-pyridinone 
• 1100932-71-5 2,4-dihydroxy-3-iodopyridine 

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