123-32-0

Basic information

• Product Name: 2,5-Dimethyl pyrazine
• Synonyms: 2,5-dimethyl-pyrazin;Pyrazine,2,5-dimethyl-;KETINE;GLYCOLINE;FEMA 3272;FEMA NUMBER 3272;FEMA NUMBER 3272 AND 3273;2,5 AND 2,6-DIMETHYL PYRAZINE
• CAS NO: 123-32-0
• Molecular Formula: C₆H₈N₂
• Molecular Weight: 108.14
• EINECS: 204-618-3
• Product Categories: Pyrazines;Pyrazine;Heterocyclic Compounds;Acipimox;Mono- & Polyalkylpyrazines;pyrazine Flavor;Building Blocks;Heterocyclic Building Blocks;Alphabetical Listings;C-D;Flavors and Fragrances;Pyrazine compounds
• Mol File: 123-32-0.mol
• Article Data: 33

Chemical Properties

• Melting Point: 15°C
• Boiling Point: 155 °C(lit.)
• Flash Point: 147 °F
• Appearance: Clear colorless to pale yellow/Liquid
• Density: 0.99 g/mL at 25 °C(lit.)
• Vapor Pressure: 3.98mmHg at 25°C
• Refractive Index: n20/D 1.502(lit.)
• Storage Temp.: Store below +30°C.
• Solubility: Chloroform (Slightly), DMSO (Slightly), Methanol (Slightly)
• PKA: 2.21±0.10(Predicted)
• Sensitive: Hygroscopic
• BRN: 107052
• CAS DataBase Reference: 2,5-Dimethyl pyrazine(CAS DataBase Reference)
• NIST Chemistry Reference: 2,5-Dimethyl pyrazine(123-32-0)
• EPA Substance Registry System: 2,5-Dimethyl pyrazine(123-32-0)

Safety Data

• Hazard Codes: Xn,Xi
• Statements: 22-36/37/38-R22
• Safety Statements: 26-36
• RIDADR: NA 1993 / PGIII
• WGK Germany: 3
• RTECS: UQ2800000
• TSCA: Yes
• Hazardous Substances Data: 123-32-0(Hazardous Substances Data)

Usage

Chemical Properties

Different sources of media describe the Chemical Properties of 123-32-0 differently. You can refer to the following data:
1. clear colorless to pale yellow liquid
2. 2,5-Dimethylpyrazine has a characteristic odor of earthy, potato-like odor.

Occurrence

Reported to be present in bakery products, roasted barley, cocoa products, roasted coffee, dairy products, pork, peanuts, pecans, filberts, popcorn, potato products, rum and whiskey, soy products; a volatile component in roasted filberts and in potato chips; reportedly identified in the fat of cooked beef; also reported found in toasted off-flavors. Also reported in cheeses, butter, boiled eggs, grilled beef, tea, barley, oats, oatmeal, soybeans, heated beans, kohlrabi, shrimp and mushrooms. Also reported found in coffee, potato chips and shrimp

Uses

Different sources of media describe the Uses of 123-32-0 differently. You can refer to the following data:
1. 2,5-Dimethyl pyrazine is used for blending food, nuts and beverage flavors.
2. 2,5-Dimethylpyrazine is used as a reagent in the synthesis of bone-targeted proteasome inhibitors for multiple myeloma (MM). 2,5-Dimethylpyrazine is also used in the preparation of 3-Methyl-2,5-bis-(2-hydroxyethyl)pyrazine (M295340); a degredation product of Clavulanic Acid (C563750) which is a β-lactamase inhibitor, typically added to amoxicillin to increase its effectiveness.

Preparation

By the interaction of acrolein and ammonia when heated in glycerol in the presence of ammonium salts; by self-condensation of aminoacetone, followed by oxidation with mercury chloride.

Aroma threshold values

Detection: 80 ppb to 1.8 ppm

Taste threshold values

Taste characteristics at 7.5 ppm: musty, potato, cocoa and nutty with a fatty and oily nuance

General Description

2,5-Dimethylpyrazine is a pyrazine compound that is mainly formed in food products such as cooked rice or roasted peanuts due to the Maillard reaction between sugars and proteins during cooking or roasting process.

Safety Profile

Moderately toxic by ingestion and intraperitoneal routes. Mutation data reported. When heated to decomposition it emits toxic fumes of NOx

Purification Methods

Purify it via its picrate (m 150o) which is decomposed with a base (e,g, KOH) and distilled. [Wiggins and Wise J Chem Soc 4780 1956]. [Beilstein 23/5 V 403.]

InChI:InChI=1/C6H8N2/c1-5-3-8-6(2)4-7-5/h3-4H,1-2H3

Synthetic route

3-amino-2-propanol (78-96-6, 1674-56-2) → 2,5-dimethyl-pyrazine (123-32-0)

Conditions	Yield
	87%
	85%
With copper oxide-chromium oxide catalyst at 275℃;

2,5-dimethylpyrimidine (22868-76-4) → 2,5-dimethyl-pyrazine (123-32-0) + 4,6-dimethylpyrimidine (1558-17-4)

Conditions	Yield
under 1 - 1.5 Torr; for 0.0833333h; Irradiation;	A 62% B 31%

2,5-dimethyl-3-chloropyrazine (95-89-6) + diethylzinc (557-20-0) → 2,5-dimethyl-pyrazine (123-32-0) + 2-ethyl-3,6-dimethylpyrazine (13360-65-1)

Conditions	Yield
With tetrakis(triphenylphosphine) palladium(0); potassium carbonate In N,N-dimethyl-formamide Heating;	A 49% B 25%

2,5-dimethyl-3-chloropyrazine (95-89-6) → 2,5-dimethyl-pyrazine (123-32-0) + 2-ethyl-3,6-dimethylpyrazine (13360-65-1)

Conditions	Yield
With tetrakis(triphenylphosphine) palladium(0); diethylzinc; potassium carbonate In N,N-dimethyl-formamide Heating;	A 49% B 25%

1-ethoxycarbonylamino-2,5-dimethyl-pyrazinium betaine (60175-11-3) → 2,5-dimethyl-pyrazine (123-32-0) + ethyl 3-methylpyrazole-N-carboxylate (60148-16-5)

Conditions	Yield
In benzene for 3h; Irradiation;	A 30% B 45%

2-Amino-1-propanol (6168-72-5) → 2,5-dimethyl-pyrazine (123-32-0)

Conditions	Yield
With C39H31BMnNO2P2; potassium hydride In toluene at 150℃; for 48h;	45%

1-azido-3-methylpentan-2-one (870544-21-1) + 1-azidopropan-2-one (4504-27-2) → 2,5-dimethyl-pyrazine (123-32-0) + 2,5-bis(1-methylpropyl)pyrazine (32435-26-0) + 2-methyl-5-(1-methylpropyl)pyrazine (29461-07-2)

Conditions	Yield
With triphenylphosphine In benzene at 20℃; for 24h;	A 36% B 20% C 34%

4,6-dimethylpyrimidine (1558-17-4) → 2,5-dimethylpyrimidine (22868-76-4) + 2,5-dimethyl-pyrazine (123-32-0)

Conditions	Yield
under 1 - 1.5 Torr; for 0.0833333h; Irradiation;	A 31% B 31%

1-aminopropan-2-one hydrochloride (7737-17-9) → 2,5-dimethyl-pyrazine (123-32-0)

Conditions	Yield
With air; sodium acetate In methanol at 60℃;	30%

1,4-dioxane (123-91-1) + 3-amino-2-propanol (78-96-6, 1674-56-2) → 2,5-dimethyl-pyrazine (123-32-0) + 2,5-dimethylpiperazine (106-55-8)

Conditions	Yield
With tributylphosphine; ruthenium trichloride	A n/a B 13.3%
With tributylphosphine; ruthenium trichloride	A n/a B 13.3%

3,6-dimethyl-pyrazine-2-carboxylic acid (2435-46-3) + acetic acid (64-19-7) → 2,5-dimethyl-pyrazine (123-32-0) + methylammonium carbonate (15719-64-9, 15719-76-3, 97762-63-5)

Conditions	Yield
at 180 - 200℃;

AlaOEt (17344-99-9) → 2,5-dimethyl-pyrazine (123-32-0)

Conditions	Yield
With hydrogenchloride; sodium amalgam Oxydation des entstandenen α-Amino-propionaldehyds mit Quecksilberchlorid in alkal. Loesung;

glycerol (56-81-5) → 2,5-dimethyl-pyrazine (123-32-0)

Conditions	Yield
bei der Destillation mit Ammoniumsalzen;
bei der Destillation mit Ammoniumsalzen;

propanone 1-oxime (306-44-5) → 2,5-dimethyl-pyrazine (123-32-0)

Conditions	Yield
With hydrogenchloride; tin Behandlung der Reaktionsprodukte mit Alkalien;
With acetic acid; zinc Behandlung der Reaktionsprodukte mit Alkalien;
With sulfuric acid Electrolysis.Behandeln der Reaktionsprodukte mit Alkalien;

2,5-dimethylpiperazine (106-55-8) → 2,5-dimethyl-pyrazine (123-32-0)

Conditions	Yield
With aluminum oxide; copper oxide-chromium oxide silicon dioxide aluminium oxide catalyst; water; silica gel at 350 - 375℃;
With Cp*Ir(6,6'-dionato-2,2'-bipyridine)(H2O) In para-xylene for 20h; Catalytic behavior; Reagent/catalyst; Solvent; Reflux; Inert atmosphere; Schlenk technique;	100 %Chromat.
With bis(1,5-cyclooctadiene)diiridium(I) dichloride In para-xylene at 160℃; for 48h; Inert atmosphere; Sealed tube;

N-acetamidoacetone (7737-16-8) → 2,5-dimethyl-pyrazine (123-32-0)

Conditions	Yield
With hydrogenchloride folgend Oxydation mit Quecksilber(II)-chlorid und Alkalilauge;

2,4-dimethyl-2-imidazoline (930-61-0) + chloroform (67-66-3) → 2,4-dimethylpyrimidine (14331-54-5) + 2,5-dimethyl-pyrazine (123-32-0) + 5-chloro-2-methylpyrimidine (54198-89-9) + 4-chloro-2,6-dimethylpyrimidine (4472-45-1)

Conditions	Yield
at 550℃; Yield given. Further byproducts given. Yields of byproduct given. Title compound not separated from byproducts;

2,4-dimethyl-2-imidazoline (930-61-0) + chloroform (67-66-3) → 2,4-dimethylpyrimidine (14331-54-5) + 2,5-dimethyl-pyrazine (123-32-0) + 2,5-dimethyl-3-chloropyrazine (95-89-6) + 2-chloro-3,5-dimethylpyrazine (38557-72-1)

Conditions	Yield
at 550℃; Yield given. Further byproducts given. Yields of byproduct given. Title compound not separated from byproducts;

2,4-dimethyl-2-imidazoline (930-61-0) + chloroform (67-66-3) → 2,5-dimethyl-pyrazine (123-32-0) + 2,5-dimethyl-3-chloropyrazine (95-89-6) + 2-chloro-3,5-dimethylpyrazine (38557-72-1) + 4-chloro-2,5-dimethylpyrimidine (75712-74-2)

Conditions	Yield
at 550℃; Yield given. Further byproducts given. Yields of byproduct given. Title compound not separated from byproducts;

2,4-dimethyl-2-imidazoline (930-61-0) + chloroform (67-66-3) → 2,5-dimethyl-pyrazine (123-32-0) + 4-chloro-2-methylpyrimidine (4994-86-9) + 2-methylimidazole (693-98-1) + 5-Chloro-2,4-dimethylpyrimidine (75712-73-1)

Conditions	Yield
at 550℃; Yield given. Further byproducts given. Yields of byproduct given. Title compound not separated from byproducts;

2,4-dimethyl-2-imidazoline (930-61-0) + chloroform (67-66-3) → 2,4-dimethylpyrimidine (14331-54-5) + 2,5-dimethyl-pyrazine (123-32-0) + 4-chloro-2,6-dimethylpyrimidine (4472-45-1) + 2,6-dimethylpyrazine (108-50-9)

Conditions	Yield
at 550℃; Yield given. Further byproducts given. Yields of byproduct given. Title compound not separated from byproducts;

2-<2-Hydroxy-2-(p-methoxyphenyl)ethyl>-5-methylpyrazine (72725-80-5) → 2,5-dimethyl-pyrazine (123-32-0) + 4-methoxy-benzaldehyde (123-11-5)

Conditions	Yield
In diethylene glycol dimethyl ether at 170℃; Rate constant;

D-(+)-Glucose (54-17-1, 492-61-5, 492-62-6, 492-66-0, 530-25-6, 530-26-7, 530-27-8, 530-28-9, 552-76-1, 579-36-2, 643-69-6, 655-45-8, 2280-44-6, 3646-73-9, 7282-78-2, 7282-79-3, 7282-80-6, 7282-81-7, 7282-82-8, 7283-02-5, 7283-08-1, 7283-09-2, 7283-10-5, 7283-11-6, 7296-15-3, 7296-64-2, 7322-31-8, 10257-28-0, 12772-65-5, 12773-29-4, 12773-31-8, 12773-32-9, 12773-33-0, 12773-34-1, 19982-85-5, 28538-24-1, 32445-46-8, 32445-47-9, 32445-51-5, 32445-52-6, 34685-56-8, 34685-57-9, 35810-56-1, 39281-65-7, 39281-66-8, 39281-67-9, 39281-68-0, 39281-69-1, 39392-61-5, 39392-62-6, 39392-63-7, 39392-65-9, 39392-66-0, 39392-69-3, 40825-84-1, 40825-86-3, 40825-87-4, 40825-89-6, 42752-07-8, 42789-83-3, 46032-76-2, 54808-89-8, 66069-07-6, 120442-57-1, 120442-58-2, 120442-59-3, 120442-67-3, 131064-91-0, 131064-92-1, 131065-00-4, 131065-01-5, 131348-38-4) → 1,4-pyrazine (290-37-9) + 2-Methylpyrazine (109-08-0) + 2,5-dimethyl-pyrazine (123-32-0) + 2,3-dimethylpyrazine (5910-89-4) + 2,6-dimethylpyrazine (108-50-9) + 2,3,5-trimethylpyrazine (14667-55-1)

Conditions	Yield
With ammonium hydroxide In glycerol for 9h; Product distribution; Heating; also with amino acids;

N-(2-hydroxypropyl)ethylenediamine (123-84-2) → 1,4-pyrazine (290-37-9) + 2-Methylpyrazine (109-08-0) + 2,5-dimethyl-pyrazine (123-32-0) + 2-ethylpyrazine (13925-00-3) + 2-methylimidazole (693-98-1) + 2-methyl-3-ethylpyrazine (15707-23-0)

Conditions	Yield
With hydrogen; 5% platinum on alumina at 350℃; Product distribution; other bifunctional Pt/Al2O3 modified catalysts;

3-amino-2-propanol (78-96-6, 1674-56-2) → 1,4-pyrazine (290-37-9) + 2-Methylpyrazine (109-08-0) + 2,5-dimethyl-pyrazine (123-32-0) + 2-ethyl-3,6-dimethylpyrazine (13360-65-1) + 2,3,5-trimethylpyrazine (14667-55-1) + 1-aminoethyl-2-methylaziridine

Conditions	Yield
With copper chromite at 180℃; for 0.333333h; Product distribution; var. temp.; other aminoalcohols;

DL-methionine (59-51-8) → 1,4-pyrazine (290-37-9) + 2-Methylpyrazine (109-08-0) + 2,5-dimethyl-pyrazine (123-32-0) + methyl 3-(methylthio)propionate (13532-18-8) + 2,3,5-trimethylpyrazine (14667-55-1) + 1-<3-(methylthio)propyl>-2-formylpyrrole

Conditions	Yield
With alpha-D-glucopyranose In water at 180℃; for 1h; Product distribution; also with methionine sulfoxide and without glucose;

2.5-dimethyl-pyrazine-carboxylic acid-(3) → 2,5-dimethyl-pyrazine (123-32-0)

Conditions	Yield
With acetic acid at 180 - 200℃;

hydrogenchloride (7647-01-0) + 2,2-diethyl-4-methyl-2,5-dihydro-1H-imidazole (102872-57-1) → 2,5-dimethyl-pyrazine (123-32-0) + pentan-3-one (96-22-0)

3-amino-2-propanol (78-96-6, 1674-56-2) + copper chromite → 2,5-dimethyl-pyrazine (123-32-0)

Conditions	Yield
at 200 - 275℃; auch mit anderen Kupfer-Katalysatoren;
at 200 - 275℃; auch mit anderen Kupfer-Katalysatoren;

2,5-dimethyl-pyrazine (123-32-0) + 2,2-difluoro-2-(2-methoxyphenyl)acetic acid (1250773-62-6) → 3-(difluoro(2-methoxyphenyl)methyl)-2,5-dimethylpyrazine

Conditions	Yield
With ammonium peroxydisulfate; silver nitrate In dichloromethane; water at 50℃; for 24h; Minisci Aromatic Substitution; Inert atmosphere; Sealed tube; regioselective reaction;	99%

2,5-dimethyl-pyrazine (123-32-0) + mesitylenesulfonylhydroxylamine (36016-40-7) → 1-Amino-2,5-dimethylpyrazin-1-ium-2,4,6-trimethylbenzenesulfonate

Conditions	Yield
In dichloromethane at 0℃; for 1h;	97%
In dichloromethane for 0.333333h; Ambient temperature;	89%

2,5-dimethyl-pyrazine (123-32-0) + 4-bromophenylglyoxylic acid (7099-87-8) → 3,6-dimethyl-2-(4-bromo)benzoylpyrazine

Conditions	Yield
With dipotassium peroxodisulfate; silver orthophosphate In dichloromethane; water at 40℃; for 24h;	97%

2,5-dimethyl-pyrazine (123-32-0) + dichloro-bis(triethylphosphine)-di-μ-chloro-diplatinum(II) → trans-{PtCl2(triethylphosphine)}2(2,5-dimethylpyrazine) (118515-84-7)

Conditions	Yield
In chloroform-d1 ligand and Pt complex (1:2 mol) in CDCl3 (or CD2Cl2) were stirred for 5 min; floating layer of hexane over soln.; elem. anal.;	95%

2,5-dimethyl-pyrazine (123-32-0) + bis(cyclopentadienyl)dimethylzirconium(IV) (12636-72-5) + C27H9BF17(1-)*C19H15(1-) + diphenyl acetylene (501-65-5) → C54H46N2Zr2(4+)*2C24BF20(1-)

Conditions	Yield
Stage #1: 2,5-dimethyl-pyrazine; bis(cyclopentadienyl)dimethylzirconium(IV); C27H9BF17(1-)*C19H15(1-) In chlorobenzene at 20℃; for 1h; Inert atmosphere; Stage #2: diphenyl acetylene In chlorobenzene at 80℃; for 12h; Inert atmosphere;	95%

2,5-dimethyl-pyrazine (123-32-0) + Benzoylformic acid (611-73-4) → 3,6-dimethylpyrazyl phenyl ketone

Conditions	Yield
With dipotassium peroxodisulfate; silver orthophosphate In dichloromethane; water at 40℃; for 24h;	95%

2,5-dimethyl-pyrazine (123-32-0) + 4-chlorophenylglyoxylic acid (7099-88-9) → 3,6-dimethyl-2-(4-chloro)benzoylpyrazine

Conditions	Yield
With dipotassium peroxodisulfate; silver orthophosphate In dichloromethane; water at 40℃; for 24h;	94%

2,5-dimethyl-pyrazine (123-32-0) + 4-methoxy-benzaldehyde (123-11-5) → 2,5-bis[2-(4-methoxyphenyl)ethenyl]pyrazine (102441-65-6)

Conditions	Yield
With potassium tert-butylate In N,N-dimethyl-formamide at 80℃; for 4h;	93%
With sodium hydroxide; tetra(n-butyl)ammonium hydrogensulfate for 3h; Heating;	20%
With zinc(II) chloride at 160℃; im Rohr;

2,5-dimethyl-pyrazine (123-32-0) + {Pt2Cl2(μ-Cl)2(PMePh2)2} (16633-87-7) → trans-{PtCl2(diphenylmethylphosphine)}2(2,5-dimethylpyrazine) (118515-90-5)

Conditions	Yield
In chloroform-d1 ligand and Pt complex (1:2 mol) in CDCl3 (or CD2Cl2) were stirred for 5 min; floating layer of hexane over soln.; elem. anal.;	93%

2,5-dimethyl-pyrazine (123-32-0)

Conditions	Yield
With potassium permanganate; potassium hydroxide In water at 60℃; for 7h; Reagent/catalyst;	92%
With selenium(IV) oxide In pyridine; water at 100 - 110℃; for 12h; Oxidation;	88%
With pyridine; selenium(IV) oxide In water for 48h; Reflux;	85%

Conditions	Yield
In acetonitrile ligand added to soln. of Cu salt, stirred for 5 h; filtered, washed with MeCN and Et2O, dried in vac.; elem. anal.;	92%

→ 3-(difluoro(4-methoxyphenyl)methyl)-2,5-dimethylpyrazine

Conditions	Yield
With ammonium peroxydisulfate; silver nitrate In dichloromethane; water at 50℃; for 24h; Catalytic behavior; Mechanism; Reagent/catalyst; Temperature; Solvent; Minisci Aromatic Substitution; Inert atmosphere; Sealed tube; regioselective reaction;	92%

2,5-dimethyl-pyrazine (123-32-0) + benzoic acid ethyl ester (93-89-0) + triphenylborane (960-71-4) → C25H21BN2O (1350300-40-1)

Conditions	Yield
Stage #1: 2,5-dimethyl-pyrazine; benzoic acid ethyl ester With sodium hydride In tetrahydrofuran; mineral oil at 20℃; for 24h; Reflux; Stage #2: triphenylborane In tetrahydrofuran at 20℃; for 24h; Inert atmosphere;	91%

2,5-dimethyl-pyrazine (123-32-0) + propionaldehyde (123-38-6) → 2-ethyl-3,6-dimethylpyrazine (13360-65-1)

Conditions	Yield
With ferrous(II) sulfate heptahydrate; sulfuric acid; dihydrogen peroxide In water at 50 - 60℃; for 6h;	90.88%
With ferrous(II) sulfate heptahydrate; sulfuric acid; dihydrogen peroxide In water at 0℃; Minisci Aromatic Substitution; Green chemistry;	45%

2,5-dimethyl-pyrazine (123-32-0) → 2,5-dimethylpyrazine-N,N'-dioxide (6890-38-6)

Conditions	Yield
With 3-chloro-benzenecarboperoxoic acid In ethyl acetate at 20℃; for 24h; Inert atmosphere;	90%
With Oxone In dichloromethane at 25℃; for 24h;	87.6%
With 3-chloro-benzenecarboperoxoic acid In ethyl acetate at 0 - 20℃; for 16h; Inert atmosphere;	86%

2,5-dimethyl-pyrazine (123-32-0) → 2,5-pyrazinedicarboxylic acid (122-05-4)

Conditions	Yield
With potassium permanganate; potassium hydroxide In water at 60℃; for 7h; Reagent/catalyst;	92%
With selenium(IV) oxide In pyridine; water at 100 - 110℃; for 12h; Oxidation;	88%
With pyridine; selenium(IV) oxide In water for 48h; Reflux;	85%

2,5-dimethyl-pyrazine (123-32-0) + copper(II) formate tetrahydrate (5893-61-8, 14690-98-3, 15305-21-2, 16842-73-2, 22992-79-6, 34729-06-1, 133386-02-4, 133386-04-6) → [Cu(II)2(formato)4(2,5-dimethylpyrazine)]n (874185-63-4)

Conditions	Yield
In acetonitrile ligand added to soln. of Cu salt, stirred for 5 h; filtered, washed with MeCN and Et2O, dried in vac.; elem. anal.;	92%

2,5-dimethyl-pyrazine (123-32-0) + 2,2-difluoro-2-(4-methoxyphenyl)acetic acid (1027513-97-8) → 3-(difluoro(4-methoxyphenyl)methyl)-2,5-dimethylpyrazine

Conditions	Yield
With ammonium peroxydisulfate; silver nitrate In dichloromethane; water at 50℃; for 24h; Catalytic behavior; Mechanism; Reagent/catalyst; Temperature; Solvent; Minisci Aromatic Substitution; Inert atmosphere; Sealed tube; regioselective reaction;	92%

2,5-dimethyl-pyrazine (123-32-0) → 2-methylpyrazin-5-carboxylic acid (5521-55-1)

Conditions	Yield
at 30℃; for 16h; Pseudomonas putida ATCC 33015;	90%
With potassium permanganate In water at 76 - 82℃; for 5.7h; Temperature; Industrial scale;	81.6%
With sodium tungstate; oxygen; cobalt(II) nitrate; manganese(ll) chloride In water	75.6%

2,5-dimethyl-pyrazine (123-32-0) + [Pt(μ-Cl)Cl(dimethylphenylphosphine)]2 → trans-{PtCl2(dimethylphenylphosphine)}2(2,5-dimethylpyrazine) (118515-89-2)

Conditions	Yield
In chloroform-d1 ligand and Pt complex (1:2 mol) in CDCl3 (or CD2Cl2) were stirred for 5 min; floating layer of hexane over soln.; elem. anal.;	90%

2,5-dimethyl-pyrazine (123-32-0) + 1,4-benzenedicarboxylic acid dimethyl ester (120-61-6) → C15H13BF2N2O3 (1350300-38-7)

Conditions	Yield
Stage #1: 2,5-dimethyl-pyrazine; 1,4-benzenedicarboxylic acid dimethyl ester With sodium hydride In tetrahydrofuran; mineral oil at 20℃; for 24h; Reflux; Stage #2: With boron trifluoride diethyl etherate; triethylamine In dichloromethane at 20℃; for 24h;	90%

2,5-dimethyl-pyrazine (123-32-0) + N-methylpyrrole aldehyde (1192-58-1) → (E,E)-2,5-bis[2-(1-methyl-1H-pyrrole-2-yl)-vinyl]-pyrazine (1365034-35-0)

Conditions	Yield
Stage #1: 2,5-dimethyl-pyrazine With potassium tert-butylate In N,N-dimethyl-formamide at 80℃; for 0.25h; Stage #2: N-methylpyrrole aldehyde In N,N-dimethyl-formamide at 80℃; for 4h;	89%
With potassium tert-butylate In N,N-dimethyl-formamide at 80℃; for 4h;	64%
With potassium tert-butylate In N,N-dimethyl-formamide at 0 - 20℃;	42%

2,5-dimethyl-pyrazine (123-32-0) + bis(pinacol)diborane (73183-34-3) → 2,5-dimethyl-1,4-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1,4-dihydropyrazine

Conditions	Yield
With 2,6-dichloro-4,4’-bipyridine In cyclohexane at 60℃; for 16h; Reagent/catalyst; Temperature; Glovebox; Inert atmosphere;	88%
In pentane N2; ligand and B compd. (1.1:1 molar ratio) stirred at room temp. for 2 h;	0%

2,5-dimethyl-pyrazine (123-32-0) + copper(II) perchlorate hexahydrate + sodium thiocyanide (540-72-7) → 2,5-dimethylpyrazinobisthiocyanatodicopper(I)

Conditions	Yield
In water addn. of an aq. soln. of Cu(ClO4)2*6H2O to an aq. soln. of 2,5-dimethylpyrazine, addn. of an aq. soln. of NaSCN to the mixt. and stirring; filtration of the yellow solid and washing with water and acetone;	87%

2,5-dimethyl-pyrazine (123-32-0) + (4-methylphenyl)(oxo)acetic acid (7163-50-0) → 3,6-dimethyl-2-(4-methyl)benzoylpyrazine

Conditions	Yield
With dipotassium peroxodisulfate; silver orthophosphate In dichloromethane; water at 40℃; for 2h;	87%

2,5-dimethyl-pyrazine (123-32-0) → pyrazinamide (98-96-4) + 2,5-pyrazinedicarboxamide (41110-27-4)

Conditions	Yield
With ammonium hydroxide; air; antimony(III) trioxide; titanium(IV) oxide; molybdenum(VI) oxide at 440℃; Oxidation; ammonolysis; demethylation;	A 5% B 86%

2,5-dimethyl-pyrazine (123-32-0) + benzoic acid ethyl ester (93-89-0) → C13H11BF2N2O (1350300-37-6)

Conditions	Yield
Stage #1: 2,5-dimethyl-pyrazine; benzoic acid ethyl ester With sodium hydride In tetrahydrofuran; mineral oil at 20℃; for 24h; Reflux; Stage #2: With boron trifluoride diethyl etherate; triethylamine In dichloromethane at 20℃; for 24h;	86%

2,5-dimethyl-pyrazine (123-32-0) + 4-dimethylamino-benzaldehyde (100-10-7) → 4,4′-(1E,1′E)-2,2′-(pyrazine-2,5-diyl)bis(ethene-2,1-diyl)bis(N,N-dimethylaniline) (502846-08-4)

Conditions	Yield
Stage #1: 2,5-dimethyl-pyrazine With potassium tert-butylate In N,N-dimethyl-formamide at 80℃; for 0.25h; Stage #2: 4-dimethylamino-benzaldehyde In N,N-dimethyl-formamide at 80℃; for 4h;	86%
With potassium tert-butylate In N,N-dimethyl-formamide at 80℃; for 4h;	72%
With potassium tert-butylate In N,N-dimethyl-formamide at 0 - 20℃;	52%
With potassium tert-butylate In N,N-dimethyl-formamide at 0℃;	52%

2,5-dimethyl-pyrazine (123-32-0) + (4-isopropylbenzaldehyde) (122-03-2) → 2,5-bis(4-isopropylstyryl)pyrazine

Conditions	Yield
Stage #1: 2,5-dimethyl-pyrazine With potassium tert-butylate In N,N-dimethyl-formamide at 80℃; for 0.25h; Stage #2: (4-isopropylbenzaldehyde) In N,N-dimethyl-formamide at 80℃; for 4h;	86%

2,5-dimethyl-pyrazine (123-32-0) + 2-(3,4-dimethylphenyl)-2,2-difluoroacetic acid → 3-((3,4-dimethylphenyl)difluoromethyl)-2,5-dimethylpyrazine

Conditions	Yield
With ammonium peroxydisulfate; silver nitrate In dichloromethane; water at 50℃; for 24h; Minisci Aromatic Substitution; Inert atmosphere; Sealed tube; regioselective reaction;	86%

2,5-dimethyl-pyrazine (123-32-0) → 2,5-dimethyl-pyrazine 1-oxide (6890-37-5)

Conditions	Yield
With sodium peroxoborate In acetic acid for 6h; Reflux;	85%
With 3,3-dimethyldioxirane In acetone at 25℃; for 0.333333h;	82%
Stage #1: 2,5-dimethyl-pyrazine With acetic acid at 0℃; Stage #2: With dihydrogen peroxide In water at 20 - 60℃;	68%
With sodium peroxoborate tetrahydrate; acetic acid at 80℃; for 6h;	60%
With dihydrogen peroxide; acetic acid

Upstream product

• 2435-46-3 3,6-dimethyl-pyrazine-2-carboxylic acid 
• 64-19-7 acetic acid 
• 17344-99-9 AlaOEt 
• 78-96-6 3-amino-2-propanol 
• 56-81-5 glycerol 
• 306-44-5 propanone 1-oxime 
• 106-55-8 2,5-dimethylpiperazine 
• 7737-16-8 N-acetamidoacetone 
• 95-89-6 2,5-dimethyl-3-chloropyrazine 
• 557-20-0 diethylzinc 
• 930-61-0 2,4-dimethyl-2-imidazoline 
• 67-66-3 chloroform 
• 72725-80-5 2-<2-Hydroxy-2-(p-methoxyphenyl)ethyl>-5-methylpyrazine 
• 60175-11-3 1-ethoxycarbonylamino-2,5-dimethyl-pyrazinium betaine 

Downstream Products

• 40790-29-2 3-butyl-2,5-dimethylpyrazine 
• 14667-55-1 2,3,5-trimethylpyrazine 
• 13360-65-1 2-ethyl-3,6-dimethylpyrazine 
• 127301-93-3 2,5-bis-(4-methyl-styryl)-pyrazine 
• 142772-07-4 2-methyl-5-(4-nitro-styryl)-pyrazine 
• 115339-36-1 2-methyl-5-styryl-pyrazine 
• 21899-24-1 2,5-(E,E)-distyrylpyrazine 
• 102441-65-6 2,5-bis[2-(4-methoxyphenyl)ethenyl]pyrazine 
• 13134-38-8 3,6-dimethylpyrazin-2-yl amine 
• 5521-55-1 2-methylpyrazin-5-carboxylic acid 
• 103150-78-3 diethyl pyrazine-2,5-dicarboxylate 
• 6890-38-6 2,5-dimethylpyrazine-N,N'-dioxide 
• 106860-97-3 2,5-dimethyl-3-phenyl-pyrazine 
• 122-05-4 2,5-pyrazinedicarboxylic acid 

Relevant articles and documents

One-pot synthesis of 2-hydroxymethyl-5-methylpyrazine from renewable 1,3-dihydroxyacetone

An efficient and green method for the synthesis of 2-hydroxymethyl-5-methylpyrazine was achieved from biomass derived 1,3-dihydroxyacetone and diammonium phosphate via a one-pot reaction. The product yield was as high as 72% under optimized conditions of pH = 8.0-9.1 at 90 °C for 1 hour in a dioxane and water mixture as a solvent. A possible reaction mechanism was proposed according to the reaction kinetics, NMR and in situ ATR-IR characterization studies.

SYNTHESIS AND CATALYTIC OXIDATION OF 2,5-DIMETHYLPYRAZINE

The classical method for obtaining 2,5-dimethylpyrazine by cyclization of aminoacetone has been improved by use of ammonium persulfate in place of mercuric chloride in the stage of catalytic oxidation of 2,5-dimethyldihydropyrazine.Catalytic vapor phase oxidation of 2,5-dimethylpyrazine gave 5-methylpyrazine-2-aldehyde and pyrazine-2,5-dialdehyde.

Comparison of pyrazines formation in methionine/glucose and corresponding Amadori rearrangement product model

The generation of pyrazines in a binary methionine/glucose (Met/Glc) mixture and corresponding methionine/glucose-derived Amadori rearrangement product (MG-ARP) was studied. Quantitative analyses of pyrazines and methional revealed that MG-ARP generated more methional compared to Met/Glc, whereas lower content and fewer species of pyrazines were observed in the MG-ARP model. Comparing the availability of α-dicarbonyl compounds generated from the Met/Glc model, methylglyoxal (MGO) was a considerably effective α-dicarbonyl compound for the formation of pyrazines during MG-ARP degradation, but glyoxal (GO) produced from MG-ARP did not effectively participate in the corresponding formation of pyrazines due to the asynchrony on the formation of GO and recovered Met. Diacetyl (DA) content was not high enough to form corresponding pyrazines in the MG-ARP model. The insufficient interaction of precursors and rapid drops in pH limited the formation of pyrazines during MG-ARP degradation. Increasing reaction temperature could reduce the negative inhibitory effect by promoting the content of precursors.

Ir-Catalyzed Reversible Acceptorless Dehydrogenation/Hydrogenation of N-Substituted and Unsubstituted Heterocycles Enabled by a Polymer-Cross-Linking Bisphosphine

The polystyrene-cross-linking bisphosphine ligand PS-DPPBz was effective for the Ir-catalyzed reversible acceptorless dehydrogenation/hydrogenation of N-heterocycles. Notably, this protocol is applicable to the dehydrogenation of N-substituted indoline derivatives with various N-substituents with different electronic and steric natures. A reaction pathway involving oxidative addition of an N-adjacent C(sp3)-H bond to a bisphosphine-coordinated Ir(I) center is proposed for the dehydrogenation of N-substituted substrates.

Synthesis of Pyrazines and Quinoxalines via Acceptorless Dehydrogenative Coupling Routes Catalyzed by Manganese Pincer Complexes

Base-metal catalyzed dehydrogenative self-coupling of 2-amino alcohols to selectively form functionalized 2,5-substituted pyrazine derivatives is presented. Also, 2-substituted quinoxaline derivatives are synthesized by dehydrogenative coupling of 1,2-diaminobenzene and 1,2-diols. In both cases, water and hydrogen gas are formed as the sole byproducts. The reactions are catalyzed by acridine-based pincer complexes of earth-abundant manganese.