5780-66-5

Basic information

• Product Name: Pyrazine-2-carbaldehyde
• Synonyms: 2-Formylpyrazine, 2-Formyl-1,4-diazine;2-pyrazinylaldehyde;Pyrazine-2-carbaldehyd;RARECHEM AK ML 0127;PYRAZINE-2-CARBALDEHYDE;PYRAZINECARBOXALDEHYDE;2-Pyrazinecarboxaldehyde;Pyrazine-2-carboxaldehyde
• CAS NO: 5780-66-5
• Molecular Formula: C₅H₄N₂O
• Molecular Weight: 108.1
• Product Categories: organic building block;Heterocycles;Aldehydes;Pyrazines, Pyrimidines & Pyridazines;Pyrazines, Pyrimidines & Pyridazines
• Mol File: 5780-66-5.mol
• Article Data: 27

Chemical Properties

• Boiling Point: 192.079 °C at 760 mmHg
• Flash Point: 70.501 °C
• Appearance: /
• Density: 1.235 g/cm³
• Storage Temp.: under inert gas (nitrogen or Argon) at 2-8°C
• PKA: -0.15±0.10(Predicted)
• CAS DataBase Reference: Pyrazine-2-carbaldehyde(CAS DataBase Reference)
• NIST Chemistry Reference: Pyrazine-2-carbaldehyde(5780-66-5)
• EPA Substance Registry System: Pyrazine-2-carbaldehyde(5780-66-5)

Safety Data

• Hazard Codes: Xi
• Statements: 36/37/38
• Safety Statements: 26-36/37/39
• HazardClass: IRRITANT
• Hazardous Substances Data: 5780-66-5(Hazardous Substances Data)

Usage

Chemical Properties

brown liquid

Synthetic route

methyl pyrazine-2-carboxylate (6164-79-0) → pyrazinecarboxaldehyde (5780-66-5)

Conditions	Yield
Stage #1: methyl pyrazine-2-carboxylate With lithium aluminium tetrahydride In tetrahydrofuran at -78 - 72℃; for 0.333333h; Stage #2: With hydrogenchloride; water	100%
With lithium aluminium tetrahydride In tetrahydrofuran at -83℃; for 2h;	68%
With lithium aluminium tetrahydride In tetrahydrofuran at -78℃; for 1.83333h; Inert atmosphere; Schlenk technique;	53.4%

2-formalpyrazine → pyrazinecarboxaldehyde (5780-66-5)

Conditions	Yield
With hydroxylamine hydrochloride; sodium acetate In ethanol at 50℃; for 2h; Temperature;	96.8%

2,5-dimethyl-pyrazine (123-32-0) → 2,5-pyrazine-dicarboxaldehyde (77666-94-5) + 5-methyl-2-pyrazinecarboxaldehyde (50866-30-3) + pyrazinecarboxaldehyde (5780-66-5)

Conditions	Yield
With air; vanadia; molybdenum(VI) oxide In water for 2.77778E-05h; Product distribution; different ratio of V:Mo, different temperature, different time of contact;	A 10% B 21% C n/a
With air; vanadia; molybdenum(VI) oxide In water at 360℃; for 2.77778E-05h;	A 10% B 21% C n/a

2-Methylpyrazine (109-08-0) → pyrazinecarboxaldehyde (5780-66-5)

Conditions	Yield
With tert.-butylhydroperoxide; selenium(IV) oxide In 1,4-dioxane for 3h; Heating;	11%

pyrazin-2-ylmethanol (6705-33-5) → pyrazinecarboxaldehyde (5780-66-5)

Conditions	Yield
With selenium(IV) oxide In 1,4-dioxane Heating;
With manganese(IV) oxide In acetone Sonication;
With Dess-Martin periodane In dichloromethane at 20℃; for 1h;	100 mg
With 2,2'-azinobis(3-ethylbenzthiazolinesulfonate); horse-radish peroxidase; choline oxidase from Arthrobacter cholorphenolicus, mutant S101A/D250G/F253R/V355T/F357R/M359R In aq. phosphate buffer at 30℃; for 24h; pH=8; Catalytic behavior; Reagent/catalyst; Enzymatic reaction;

2-Methylpyrazine (109-08-0) → pyrazinecarboxaldehyde (5780-66-5) + carbon oxides

Conditions	Yield
β-VO(PO3)2 In gas at 400℃; Product distribution; Rate constant; selectivity of reaction, rates of partial and total oxidation;

2-pyrazylcarboxylic acid (98-97-5) → pyrazinecarboxaldehyde (5780-66-5)

Conditions	Yield
Multi-step reaction with 2 steps 1: 95 percent / conc. H2SO4 / 48 h / Heating 2: 26 percent / DIBAL / CH2Cl2 View Scheme

pyrazine carboxaldehyde diethyl acetal (67936-72-5) + N-methoxylamine hydrochloride (593-56-6) → pyrazinecarboxaldehyde (5780-66-5)

Conditions	Yield
With sodium hydrogencarbonate In chloroform; Petroleum ether

2-Methylpyrazine (109-08-0) → 2-methylpyrazine 4-oxide (25594-37-0) + 2-methylpyrazine 1-oxide (31396-35-7) + 2-pyrazylcarboxylic acid (98-97-5) + pyrazinecarboxaldehyde (5780-66-5) + pyrazine-2-carboxylic acid-4-oxide (874-54-4) + pyrazine-2-carboxylic acid-1-oxide (32046-09-6)

Conditions	Yield
With acetyl peroxyborate In water at 94.84℃; for 5h;	A n/a B n/a C 56.3 mol % D 4.5 mol % E n/a F n/a
With acetyl peroxyborate In water at 94.84℃; for 5h;	A n/a B n/a C 28.5 mol % D 41.2 mol % E n/a F n/a

2-Methylpyrazine (109-08-0) + acetic acid (64-19-7) → acetate de (pyrazinyl-2) methyle (73763-94-7) + pyrazinecarboxaldehyde (5780-66-5)

Conditions	Yield
With copper(l) iodide; oxygen; palladium diacetate at 120℃; for 24h; Autoclave;

ethylenediamine (107-15-3) + glycerol (56-81-5) → 1,4-pyrazine (290-37-9) + 2-Methylpyrazine (109-08-0) + 2,5-dimethyl-pyrazine (123-32-0) + 2,3-dimethylpyrazine (5910-89-4) + pyrazinecarboxaldehyde (5780-66-5)

Conditions	Yield
With calcined ZnO-ZnCr2O4 catalyst In water at 300 - 400℃; under 760.051 Torr;

ethylenediamine (107-15-3) + glycerol (56-81-5) → 1,4-pyrazine (290-37-9) + 2-Methylpyrazine (109-08-0) + 2,5-dimethyl-pyrazine (123-32-0) + 2,3-dimethylpyrazine (5910-89-4) + pyrazin-2-ylmethanol (6705-33-5) + 2,6-dimethylpyrazine (108-50-9) + pyrazinecarboxaldehyde (5780-66-5)

Conditions	Yield
In water at 375℃; under 760.051 Torr; for 6h; Inert atmosphere; Flow reactor;

...Expand

pyrazinecarboxaldehyde (5780-66-5) + 2-aminomethylpyrazine (20010-99-5) → (E)-1-(pyrazin-2-yl)-N-(pyrazin-2-ylmethyl)methanimine

Conditions	Yield
Stage #1: pyrazinecarboxaldehyde; 2-aminomethylpyrazine In dichloromethane for 0.0833333h; Inert atmosphere; Stage #2: With sodium sulfate In dichloromethane at 20℃; for 0.75h; Inert atmosphere; Darkness;	100%

(E)-(2-nitrovinyl)cyclohexane (50598-92-0, 132839-80-6) + pyrazinecarboxaldehyde (5780-66-5) → (S)-2-cyclohexyl-3-nitro-1-(pyrazin-2-yl)propan-1-one (1175052-23-9)

Conditions	Yield
With (5R,7R)-7-fluoro-5-isopropyl-2-(perfluorophenyl)-6,7-dihydro-5H-pyrrolo[2,1c][1,2,4]triazol-2-ium tetrafluoroborate; N-ethyl-N,N-diisopropylamine In methanol at 0℃; Stetter reaction; Inert atmosphere; optical yield given as %ee; enantioselective reaction;	99%

nitromethane (75-52-5) + pyrazinecarboxaldehyde (5780-66-5) → 2-nitro-1-pyrazin-2-yl-ethanol (854928-19-1)

Conditions	Yield
With triethylamine at 20℃; for 1h;	93.3%
With potassium tert-butylate In tetrahydrofuran at 0 - 5℃; for 0.25h;	64%

pyrazinecarboxaldehyde (5780-66-5) + 1-t-Butoxycarbonylpiperazine (57260-71-6) → tert-butyl 4-(pyrazin-2-ylmethyl)piperazine-1-carboxylate (1402710-03-5)

Conditions	Yield
With sodium triacetoxy borohydride; acetic acid In dichloromethane at 20℃; for 6.5h;	91%

pyrazinecarboxaldehyde (5780-66-5) → 2-(difluoromethyl)pyrazine (111781-48-7)

Conditions	Yield
With XtalFluor-E; triethylamine tris(hydrogen fluoride) In dichloromethane at 20℃;	90%
With (diethylamido)sulfur trifluoride In trichlorofluoromethane at 20℃;	39%

pyrazinecarboxaldehyde (5780-66-5) + toluene-4-sulfonic acid hydrazide (1576-35-8) → 4-methyl-N'-(pyrazin-2-ylmethylene)benzenesulfonohydrazide

Conditions	Yield
In methanol at 60℃; for 0.5h;	90%

(2-aminomethylpyridine) (3731-51-9) + pyrazinecarboxaldehyde (5780-66-5) → (2-picolyl)-(pyrazin-2-yl-methyl)amine (1084898-22-5)

Conditions	Yield
Stage #1: 2-(Aminomethyl)pyridine; pyrazinecarboxaldehyde In methanol at 25℃; for 0.5h; Stage #2: With sodium tetrahydroborate In methanol at 25℃; for 2h;	90%

3-methoxy-2-methylquinoline (84689-36-1) + pyrazinecarboxaldehyde (5780-66-5) → C16H13N3O

Conditions	Yield
With toluene-4-sulfonamide In toluene at 120℃; for 12h; Inert atmosphere;	89%

8-methoxy-2-methylquinoline (3033-80-5) + pyrazinecarboxaldehyde (5780-66-5) → C16H13N3O

Conditions	Yield
With toluene-4-sulfonamide In toluene at 120℃; for 12h; Inert atmosphere;	87%

t-butoxycarbonylhydrazine (870-46-2) + pyrazinecarboxaldehyde (5780-66-5) → tert-butyl N-[(E)-pyrazin-2-ylmethyleneamino]carbamate

Conditions	Yield
In dichloromethane at 20℃; for 16h;	87%

2-furanoic acid (88-14-2) + tert-butylisonitrile (119072-55-8, 7188-38-7) + 4-tert-Butylaniline (769-92-6) + pyrazinecarboxaldehyde (5780-66-5) → N-tert-butyl-2-[N-(4-tert-butylphenyl)-1-(furan-2-yl)formamido]-2-(pyrazin-2-yl)acetamide (1417700-04-9)

Conditions	Yield
Stage #1: 4-tert-Butylaniline; pyrazinecarboxaldehyde In methanol at 20℃; for 0.5h; Ugi Condensation; Inert atmosphere; Stage #2: 2-furanoic acid; tert-butylisonitrile In methanol at 20℃; Ugi Condensation; Inert atmosphere;	86%
In methanol at 20℃; for 16h; Ugi Condensation;

6-methoxyquinaldine (1078-28-0) + pyrazinecarboxaldehyde (5780-66-5) → C16H13N3O

Conditions	Yield
With toluene-4-sulfonamide In toluene at 120℃; for 12h; Inert atmosphere;	85%

4-methoxy-2-methyl-quinoline (31835-53-7) + pyrazinecarboxaldehyde (5780-66-5) → C16H13N3O

Conditions	Yield
With toluene-4-sulfonamide In toluene at 120℃; for 12h; Inert atmosphere;	83%

2-furanoic acid (88-14-2) + 4-Aminobiphenyl (92-67-1) + (S)-1-isocyano-1-phenylethane (17329-20-3, 21872-32-2, 21872-33-3, 42412-74-8) + pyrazinecarboxaldehyde (5780-66-5) → 2-(N-{[1,1′-biphenyl]-4-yl}-1-(furan-2-yl)formamido)-N-[(1S)1-phenylethyl]-2-(pyrazin-2-yl)acetamide

Conditions	Yield
Stage #1: 4-phenylalanine; pyrazinecarboxaldehyde In methanol at 20℃; for 0.5h; Ugi Condensation; Inert atmosphere; Stage #2: 2-furanoic acid; (S)-1-isocyano-1-phenylethane In methanol at 20℃; Ugi Condensation; Inert atmosphere;	83%

[2-(3-bromo-benzo[b]thiophen-2-yl)-ethyl]dimethyl-amine (873692-91-2) + pyrazinecarboxaldehyde (5780-66-5) + trifluoroacetic acid (76-05-1) → [2-(2-dimethylamino-ethyl)-benzo[b]thiophen-3-yl]-pyrazin-2-yl-methanol trifluoroacetate (1186219-29-3)

Conditions	Yield
Stage #1: [2-(3-bromo-benzo[b]thiophen-2-yl)-ethyl]dimethyl-amine With n-butyllithium; N,N,N,N,-tetramethylethylenediamine In hexane; toluene at -78℃; Stage #2: pyrazinecarboxaldehyde In hexane; toluene at -78 - 0℃; Stage #3: trifluoroacetic acid In water; acetonitrile	82%

5-methoxy-2-methylquinoline (79205-04-2) + pyrazinecarboxaldehyde (5780-66-5) → C16H13N3O

Conditions	Yield
With toluene-4-sulfonamide In toluene at 120℃; for 12h; Inert atmosphere;	82%

6-bromoquinoline-2,4-diol + pyrazinecarboxaldehyde (5780-66-5) → 6-bromo-3-(pyrazin-2-ylmethyl)quinoline-2,4-diol

Conditions	Yield
With pyridine; diethyl 2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate at 100℃; for 4h; Knoevenagel Condensation;	82%

7-methoxy-2-methylquinoline (19490-87-0) + pyrazinecarboxaldehyde (5780-66-5) → C16H13N3O

Conditions	Yield
With toluene-4-sulfonamide In toluene at 120℃; for 12h; Inert atmosphere;	80%

pyrazinecarboxaldehyde (5780-66-5) + malonic acid dimethyl ester (108-59-8) → dimethyl 2-(pyrazin-2-ylmethylene)malonate

Conditions	Yield
With piperidine; acetic acid In toluene at 110℃; for 18h; Inert atmosphere; Schlenk technique; Sealed tube;	80%

allyltriphenylphosphonium bromide (1560-54-9) + pyrazinecarboxaldehyde (5780-66-5) → 2-(buta-1,3-dien-1-yl)pyrazine

Conditions	Yield
Stage #1: allyltriphenylphosphonium bromide In tetrahydrofuran; hexane at 0℃; for 0.25h; Inert atmosphere; Stage #2: pyrazinecarboxaldehyde In tetrahydrofuran; hexane for 1h; Inert atmosphere;	79%

pyrazinecarboxaldehyde (5780-66-5) + benzylamine (100-46-9) → C12H13N3

Conditions	Yield
With sodium cyanoborohydride; acetic acid at 100℃; for 14h; Flow reactor;	76%

4-[3-fluoro-4-(methylsulfanyl)phenyl]-5-(tetrahydro-2H-pyran-4-yl)pent-1-en-3-one (1080061-14-8) + pyrazinecarboxaldehyde (5780-66-5) → 5-[3-fluoro-4-(methylsulfanyl)phenyl]-1-(pyrazin-2-yl)-6-(tetrahydro-2H-pyran-4-yl)hexane-1,4-dione (1080061-16-0)

Conditions	Yield
With 3-benzyl-5-(2-hydroxyethyl)-4-methyl-1,3-thiazol-3-ium chloride; triethylamine In ethanol for 2h; Reflux;	75%

pyrazinecarboxaldehyde (5780-66-5) → 1,2-di(pyrazin-2-yl)ethene-1,2-diol (93691-18-0)

Conditions	Yield
With potassium cyanide In water at 20℃; for 1h;	73%

phenylmagnesium chloride (100-59-4) + pyrazinecarboxaldehyde (5780-66-5) → (α-hydroxybenzyl)pyrazine (98792-43-9)

Conditions	Yield
In tetrahydrofuran at -78 - 20℃; for 0.25h;	73%

pyrazinecarboxaldehyde (5780-66-5) + (R)-2-methylpropane-2-sulfinamide (196929-78-9) → (R,E)-2-methyl-N-(pyrazin-2-ylmethylene)propane-2-sulfinamide (1421236-66-9)

Conditions	Yield
With caesium carbonate In dichloromethane at 20℃; Inert atmosphere;	72%

4,4'-diamino diphenyl methane (101-77-9) + pyrazinecarboxaldehyde (5780-66-5) → C22H17N7

Conditions	Yield
In ethanol at 20℃; for 24h;	71%

rhodanine 3-acetic acid (5718-83-2) + pyrazinecarboxaldehyde (5780-66-5) → [(5Z)-4-oxo-5-(pyrazin-2-ylmethylene)-2-thioxo-1,3-thiazolidin-3-yl]acetic acid

Conditions	Yield
With sodium acetate; acetic anhydride; acetic acid for 3h; Reflux;	71%

Upstream product

• 123-32-0 2,5-dimethyl-pyrazine 
• 109-08-0 2-Methylpyrazine 
• 107-15-3 ethylenediamine 
• 56-81-5 glycerol 
• 64-19-7 acetic acid 
• 67936-72-5 pyrazine carboxaldehyde diethyl acetal 
• 593-56-6 N-methoxylamine hydrochloride 
• 98-97-5 2-pyrazylcarboxylic acid 
• 6164-79-0 methyl pyrazine-2-carboxylate 
• 6705-33-5 pyrazin-2-ylmethanol 

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