2,3,5-Trimethylpyrazine

Last updated
2,3,5-Trimethylpyrazine
2,3,5-trimethylpyrazine.png
Names
IUPAC name
2,3,5-Trimethylpyrazine
Other names
Pyrazine, 2,3,5-trimethyl-;2,3,5-Trimethyl pyrazine;2,3,5-Trimethyl pyrazine (natural);2,3,5-Trimethylpyrazine;2,3,6-Trimethylpyrazine;5-23-05-00419 (Beilstein Handbook Reference);AI3-34442;BRN 0002423;CCRIS 2932;FEMA No. 3244;Pyrazine, trimethyl-;Trimethylpyrazine
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.035.178 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 238-712-0
PubChem CID
UNII
  • InChI=1S/C7H10N2/c1-5-4-8-6(2)7(3)9-5/h4H,1-3H3
    Key: IAEGWXHKWJGQAZ-UHFFFAOYSA-N
  • CC1=CN=C(C(=N1)C)C
Properties
C7H10N2
Molar mass 122.171 g·mol−1
Appearancecolourless to slightly yellow liquid
Odor roasted nut, baked potato odour
Density 0.979 g mL−1
Boiling point 173.1 °C (343.6 °F; 446.2 K)
Alcohol, oils, water (1.521e+004 mg/L at 25 °C (est)
1.5030 to 1.5050
Hazards
GHS labelling:
GHS-pictogram-flamme.svg GHS-pictogram-exclam.svg
Warning
H226, H302
P210, P233, P240, P241, P242, P243, P264, P270, P280, P301+P312, P303+P361+P353, P330, P370+P378, P403+P235, P501
Flash point 54.4 °C (129.9 °F; 327.5 K)
Lethal dose or concentration (LD, LC):
806 mg/kg rat
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

2,3,5-Trimethylpyrazine (chemical formula C7H10N2) is one of the most broadly used edible synthesis fragrances. It comes from baked food, fried barley, potatoes, and peanuts. 2,3,5-Trimethylpyrazine is used for the flavor in cocoa, coffee, chocolate, potato, cereal, and fried nuts.

Contents

Physical properties

The specific gravity depends on the quality and the producer and ranges from 0.967 to 0.987.

Synthesis

2,3,5-Trimethylpyrazine can be synthesized from 2,3-butanedione and 1,2-diaminopropane. First, 1,2-diaminopropane is synthesized by amination of isopropanolamine in the presence of ammonia and a hydrogenation catalyst: Raney Ni. The effect of the amount of Raney Ni catalyst, the molar ratio of materials, reactions are as follows: the molar ratio of isopropanolamine to ammomia is 1:3.5,the reaction temperature is 160 °C, the reaction is 5 hours, the molar ratio of hydrogen to isopropanolamine is 1:5. Then the reaction consists of synthesis of 2,3,5-trimethyl-5,6-dihydropyrazine and 2,3,5-trimethylpyrazine. The optimum conditions of 2,3,5-trimethyl-5,6-dihydropropyrazine synthesis are established:2,3-butanedione which is mixed with anhydrous ethyl alcohol (the mass ratio of anhydrous ethyl alcohol to 2,3-butanedione was 5:1) is dropped to the mixture of anhydrous ethyl alcohol and 1,2-diaminopropane (the mass ratio of anhydrous ethyl alcohol to 1,2-diaminopropane was 6:1) at the even pace for four hours, the molar ratio of 2,3-butanedione to 1,2-diaminopropane is 1:1.1, the condensation reaction temperature is -5 °C. The best dehydrogen oxidation conditions are as follows: air is used as oxidant, the molar ration of potassium hydroxide and 2,3,5-Trimethyl-5,6-dihydro-pyrazine is 3:1, the mass ratio of ethanol to 2,3,5-trimethyl-5,6-dihydro-pyrazine 10:1,reaction temperature 68 °C, reaction time seven hours. [1]

There are several other ways to synthesis 2,3,5-trimethylpyrazine:

RXN 1.png
RXN 2.png
RXN 3.png
RXN 4.png

Use limit in food

FEMA (mg/kg)
Soft drinks 5.0~10
Candy 5.0~10
Baked food 5.0~10
Cereal 2.0
Seasoning 2.0
Meat 2.0
Dairy 1.0
Soup 2.0

Related Research Articles

<span class="mw-page-title-main">Ethanol</span> Organic compound (CH₃CH₂OH)

Ethanol is an organic compound. It is an alcohol with the chemical formula C2H6O. Its formula can also be written as CH3−CH2−OH or C2H5OH. Ethanol is a volatile, flammable, colorless liquid with a characteristic wine-like odor and pungent taste. It is a psychoactive recreational drug, and the active ingredient in alcoholic drinks.

<span class="mw-page-title-main">Aldol condensation</span> Type of chemical reaction

An aldol condensation is a condensation reaction in organic chemistry in which two carbonyl moieties react to form a β-hydroxyaldehyde or β-hydroxyketone, and this is then followed by dehydration to give a conjugated enone.

<span class="mw-page-title-main">Fischer–Speier esterification</span>

Fischer esterification or Fischer–Speier esterification is a special type of esterification by refluxing a carboxylic acid and an alcohol in the presence of an acid catalyst. The reaction was first described by Emil Fischer and Arthur Speier in 1895. Most carboxylic acids are suitable for the reaction, but the alcohol should generally be primary or secondary. Tertiary alcohols are prone to elimination. Contrary to common misconception found in organic chemistry textbooks, phenols can also be esterified to give good to near quantitative yield of products. Commonly used catalysts for a Fischer esterification include sulfuric acid, p-toluenesulfonic acid, and Lewis acids such as scandium(III) triflate. For more valuable or sensitive substrates other, milder procedures such as Steglich esterification are used. The reaction is often carried out without a solvent or in a non-polar solvent to facilitate the Dean-Stark method. Typical reaction times vary from 1–10 hours at temperatures of 60-110 °C.

In organic chemistry, hydroformylation, also known as oxo synthesis or oxo process, is an industrial process for the production of aldehydes from alkenes. This chemical reaction entails the net addition of a formyl group and a hydrogen atom to a carbon-carbon double bond. This process has undergone continuous growth since its invention: production capacity reached 6.6×106 tons in 1995. It is important because aldehydes are easily converted into many secondary products. For example, the resulting aldehydes are hydrogenated to alcohols that are converted to detergents. Hydroformylation is also used in speciality chemicals, relevant to the organic synthesis of fragrances and drugs. The development of hydroformylation is one of the premier achievements of 20th-century industrial chemistry.

Methylamine is an organic compound with a formula of CH3NH2. This colorless gas is a derivative of ammonia, but with one hydrogen atom being replaced by a methyl group. It is the simplest primary amine.

<span class="mw-page-title-main">Ethyl acetate</span> Organic compound (CH₃CO₂CH₂CH₃)

Ethyl acetate is the organic compound with the formula CH3CO2CH2CH3, simplified to C4H8O2. This colorless liquid has a characteristic sweet smell and is used in glues, nail polish removers, and in the decaffeination process of tea and coffee. Ethyl acetate is the ester of ethanol and acetic acid; it is manufactured on a large scale for use as a solvent.

<span class="mw-page-title-main">Trimethylaluminium</span> Chemical compound

Trimethylaluminium is one of the simplest examples of an organoaluminium compound. Despite its name it has the formula Al2(CH3)6 (abbreviated as Al2Me6 or TMA), as it exists as a dimer. This colorless liquid is pyrophoric. It is an industrially important compound, closely related to triethylaluminium.

Chloral, also known as trichloroacetaldehyde or trichloroethanal, is the organic compound with the formula Cl3CCHO. This aldehyde is a colourless liquid that is soluble in a wide range of solvents. It reacts with water to form chloral hydrate, a once widely used sedative and hypnotic substance.

<span class="mw-page-title-main">Sodium ethoxide</span> Ionic compound made of a C2H5–O anion and a sodium cation

Sodium ethoxide, also referred to as sodium ethylate, is the ionic, organic compound with the formula C2H5ONa, or NaOEt. It is a white solid, although impure samples appear yellow or brown. It dissolves in polar solvents such as ethanol. It is commonly used as a strong base.

<span class="mw-page-title-main">Hantzsch ester</span> Chemical compound

Hantzsch ester refers to an organic compound with the formula HN(MeC=C(CO2Et))2CH2 where Me = methyl (CH3) and Et = ethyl (C2H5). It is a light yellow solid. The compound is an example of a 1,4-dihydropyridine. It is named after Arthur Rudolf Hantzsch who described its synthesis in 1881. The compound is a hydride donor, e.g., for reduction of imines to amines. It is a synthetic analogue of NADH, a naturally occurring dihydropyridine.

<span class="mw-page-title-main">Trimethylsilyl chloride</span> Chemical compound

Trimethylsilyl chloride, also known as chlorotrimethylsilane is an organosilicon compound (silyl halide), with the formula (CH3)3SiCl, often abbreviated Me3SiCl or TMSCl. It is a colourless volatile liquid that is stable in the absence of water. It is widely used in organic chemistry.

Tetrahydropyran (THP) is the organic compound consisting of a saturated six-membered ring containing five carbon atoms and one oxygen atom. It is named by reference to pyran, which contains two double bonds, and may be produced from it by adding four hydrogens. In 2013, its preferred IUPAC name was established as oxane. The compound is a colourless volatile liquid. Derivatives of tetrahydropyran are, however, more common. 2-Tetrahydropyranyl (THP-) ethers derived from the reaction of alcohols and 3,4-dihydropyran are commonly used as protecting groups in organic synthesis. Furthermore, a tetrahydropyran ring system, i.e., five carbon atoms and an oxygen, is the core of pyranose sugars, such as glucose.

<span class="mw-page-title-main">Carbonate ester</span> Chemical group (R–O–C(=O)–O–R)

In organic chemistry, a carbonate ester is an ester of carbonic acid. This functional group consists of a carbonyl group flanked by two alkoxy groups. The general structure of these carbonates is R−O−C(=O)−O−R' and they are related to esters, ethers and also to the inorganic carbonates.

<span class="mw-page-title-main">Ortho ester</span> Chemical group with the structure RC(OR)3

In organic chemistry, an ortho ester is a functional group containing three alkoxy groups attached to one carbon atom, i.e. with the general formula RC(OR′)3. Orthoesters may be considered as products of exhaustive alkylation of unstable orthocarboxylic acids and it is from these that the name 'ortho ester' is derived. An example is ethyl orthoacetate, CH3C(OCH2CH3)3, more correctly known as 1,1,1-triethoxyethane.

<span class="mw-page-title-main">Triethyl orthoformate</span> Chemical compound

Triethyl orthoformate is an organic compound with the formula HC(OC2H5)3. This colorless volatile liquid, the orthoester of formic acid, is commercially available. The industrial synthesis is from hydrogen cyanide and ethanol.

<span class="mw-page-title-main">Etonitazene</span> Chemical compound

Etonitazene, also known as EA-4941 or CS-4640, is a benzimidazole opioid, first reported in 1957, that has been shown to have approximately 1,000 to 1,500 times the potency of morphine in animals.

The Chichibabin pyridine synthesis is a method for synthesizing pyridine rings. The reaction involves the condensation reaction of aldehydes, ketones, α,β-Unsaturated carbonyl compounds, or any combination of the above, with ammonia. It was reported by Aleksei Chichibabin in 1924. Methyl-substituted pyridines, which show widespread uses among multiple fields of applied chemistry, are prepared by this methodology.

<span class="mw-page-title-main">Methylpentynol</span> Chemical compound

Methylpentynol is a tertiary hexynol with hypnotic/sedative and anticonvulsant effects and an exceptionally low therapeutic index. It was discovered by Bayer in 1913 and was used shortly thereafter for the treatment of insomnia, but its use was quickly phased out in response to newer drugs with far more favorable safety profiles.

<span class="mw-page-title-main">Trimethyl phosphite</span> Chemical compound

Trimethyl phosphite is an organophosphorus compound with the formula P(OCH3)3, often abbreviated P(OMe)3. It is a colorless liquid with a highly pungent odor. It is the simplest phosphite ester and finds used as a ligand in organometallic chemistry and as a reagent in organic synthesis. The molecule features a pyramidal phosphorus(III) center bound to three methoxy groups.

<span class="mw-page-title-main">Oxazoline</span> Chemical compound

Oxazoline is a five-membered heterocyclic organic compound with the formula C3H5NO. It is the parent of a family of compounds called oxazolines, which contain non-hydrogenic substituents on carbon and/or nitrogen. Oxazolines are the unsaturated analogues of oxazolidines, and they are isomeric with isoxazolines, where the N and O are directly bonded. Two isomers of oxazoline are known, depending on the location of the double bond.

References

  1. "2,3,5-三甲基吡嗪的合成研究" [Study on the synthesis of 2,3,5-trimethylpyrazine].{{cite journal}}: Cite journal requires |journal= (help)

Additional references