2,6-Lutidine

Last updated
2,6-Lutidine [1]
2,6-Lutidine.svg
Names
Preferred IUPAC name
2,6-Dimethylpyridine
Other names
Lutidine
Identifiers
3D model (JSmol)
105690
ChEBI
ChemSpider
ECHA InfoCard 100.003.262 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 203-587-3
2863
PubChem CID
UNII
UN number 2734
  • InChI=1S/C7H9N/c1-6-4-3-5-7(2)8-6/h3-5H,1-2H3
    Key: OISVCGZHLKNMSJ-UHFFFAOYSA-N
  • CC1=CC=CC(C)=N1
Properties
C7H9N
Molar mass 107.153 g/mol
Appearancecolorless oily liquid
Density 0.9252
Melting point −5.8 °C (21.6 °F; 267.3 K)
Boiling point 144 °C (291 °F; 417 K)
27.2% at 45.3 °C
Acidity (pKa)6.72 [2]
−71.72×10−6 cm3/mol
Hazards
NFPA 704 (fire diamond)
NFPA 704.svgHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 3: Liquids and solids that can be ignited under almost all ambient temperature conditions. Flash point between 23 and 38 °C (73 and 100 °F). E.g. gasolineInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
2
3
0
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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2,6-Lutidine is a natural heterocyclic aromatic organic compound with the formula (CH3)2C5H3N. It is one of several dimethyl-substituted derivative of pyridine, all of which are referred to as lutidines. It is a colorless liquid with mildly basic properties and a pungent, noxious odor.

Contents

Occurrence and production

It was first isolated from the basic fraction of coal tar and from bone oil. [1]

A laboratory route involves condensation of ethyl acetoacetate, formaldehyde, and an ammonia source to give a bis(carboxy ester) of a 2,6-dimethyl-1,4-dihydropyridine, which, after hydrolysis, undergoes decarboxylation. [3]

It is produced industrially by the reaction of formaldehyde, acetone, and ammonia. [2]

Uses

2,6-Lutidine has been evaluated for use as a food additive owing to its nutty aroma when present in solution at very low concentrations.

Due to the steric effects of the two methyl groups, 2,6-lutidine is less nucleophilic than pyridine. Protonation of lutidine gives lutidinium, [(CH3)2C5H3NH]+, salts of which are sometimes used as a weak acid because the conjugate base (2,6-lutidine) is so weakly coordinating. In a similar implementation, 2,6-lutidine is thus sometimes used in organic synthesis as a sterically hindered mild base. [4] One of the most common uses for 2,6-lutidine is as a non-nucleophilic base in organic synthesis. It takes part in the formation of silyl ethers as shown in multiple studies. [5] [6]

Oxidation of 2,6-lutidine with air gives 2,6-diformylpyridine:

C5H3N(CH3)2 + 2 O2 → C5H3N(CHO)2 + 2 H2O

Biodegradation

The biodegradation of pyridines proceeds via multiple pathways. [7] Although pyridine is an excellent source of carbon, nitrogen, and energy for certain microorganisms, methylation significantly retards degradation of the pyridine ring. In soil, 2,6-lutidine is significantly more resistant to microbiological degradation than any of the picoline isomers or 2,4-lutidine. [8] Estimated time for complete degradation was over 30 days. [9]

See also

Toxicity

Like most alkylpyridines, the LD50 of 2,6-dimethylpyridine is modest, being 400 mg/kg (oral, rat). [2]

Related Research Articles

<span class="mw-page-title-main">Ester</span> Compound derived from an acid

In chemistry, an ester is a functional group derived from an acid in which the hydrogen atom (H) of at least one acidic hydroxyl group of that acid is replaced by an organyl group. Analogues derived from oxygen replaced by other chalcogens belong to the ester category as well. According to some authors, organyl derivatives of acidic hydrogen of other acids are esters as well, but not according to the IUPAC.

Demethylation is the chemical process resulting in the removal of a methyl group (CH3) from a molecule. A common way of demethylation is the replacement of a methyl group by a hydrogen atom, resulting in a net loss of one carbon and two hydrogen atoms.

<span class="mw-page-title-main">Imine</span> Organic compound or functional group containing a C=N bond

In organic chemistry, an imine is a functional group or organic compound containing a carbon–nitrogen double bond. The nitrogen atom can be attached to a hydrogen or an organic group (R). The carbon atom has two additional single bonds. Imines are common in synthetic and naturally occurring compounds and they participate in many reactions.

<span class="mw-page-title-main">Anisole</span> Organic compound (CH₃OC₆H₅) also named methoxybenzene

Anisole, or methoxybenzene, is an organic compound with the formula CH3OC6H5. It is a colorless liquid with a smell reminiscent of anise seed, and in fact many of its derivatives are found in natural and artificial fragrances. The compound is mainly made synthetically and is a precursor to other synthetic compounds. Structurally, it is an ether with a methyl and phenyl group attached. Anisole is a standard reagent of both practical and pedagogical value.

The Simmons–Smith reaction is an organic cheletropic reaction involving an organozinc carbenoid that reacts with an alkene to form a cyclopropane. It is named after Howard Ensign Simmons, Jr. and Ronald D. Smith. It uses a methylene free radical intermediate that is delivered to both carbons of the alkene simultaneously, therefore the configuration of the double bond is preserved in the product and the reaction is stereospecific.

<i>tert</i>-Butyl alcohol Chemical compound

tert-Butyl alcohol is the simplest tertiary alcohol, with a formula of (CH3)3COH (sometimes represented as t-BuOH). Its isomers are 1-butanol, isobutanol, and butan-2-ol. tert-Butyl alcohol is a colorless solid, which melts near room temperature and has a camphor-like odor. It is miscible with water, ethanol and diethyl ether.

Silyl ethers are a group of chemical compounds which contain a silicon atom covalently bonded to an alkoxy group. The general structure is R1R2R3Si−O−R4 where R4 is an alkyl group or an aryl group. Silyl ethers are usually used as protecting groups for alcohols in organic synthesis. Since R1R2R3 can be combinations of differing groups which can be varied in order to provide a number of silyl ethers, this group of chemical compounds provides a wide spectrum of selectivity for protecting group chemistry. Common silyl ethers are: trimethylsilyl (TMS), tert-butyldiphenylsilyl (TBDPS), tert-butyldimethylsilyl (TBS/TBDMS) and triisopropylsilyl (TIPS). They are particularly useful because they can be installed and removed very selectively under mild conditions.

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

Phenyllithium is an organometallic agent with the empirical formula C6H5Li. It is most commonly used as a metalating agent in organic syntheses and a substitute for Grignard reagents for introducing phenyl groups in organic syntheses. Crystalline phenyllithium is colorless; however, solutions of phenyllithium are various shades of brown or red depending on the solvent used and the impurities present in the solute.

<span class="mw-page-title-main">Lutidine</span> Index of chemical compounds with the same name

Lutidine is the trivial name used to describe the chemical compounds which are dimethyl derivatives of pyridine. Their chemical properties resemble those of pyridine, although the presence of the methyl groups may prohibit some of the more straightforward reactions. Lutidine comes in several isomers:

<i>tert</i>-Butyllithium Chemical compound

tert-Butyllithium is a chemical compound with the formula (CH3)3CLi. As an organolithium compound, it has applications in organic synthesis since it is a strong base, capable of deprotonating many carbon molecules, including benzene. tert-Butyllithium is available commercially as solutions in hydrocarbons (such as pentane); it is not usually prepared in the laboratory.

<span class="mw-page-title-main">Palladium on carbon</span> Chemical compound

Palladium on carbon, often referred to as Pd/C, is a form of palladium used as a catalyst. The metal is supported on activated carbon to maximize its surface area and activity.

<span class="mw-page-title-main">Dakin oxidation</span> Organic redox reaction that converts hydroxyphenyl aldehydes or ketones into benzenediols

The Dakin oxidation (or Dakin reaction) is an organic redox reaction in which an ortho- or para-hydroxylated phenyl aldehyde (2-hydroxybenzaldehyde or 4-hydroxybenzaldehyde) or ketone reacts with hydrogen peroxide (H2O2) in base to form a benzenediol and a carboxylate. Overall, the carbonyl group is oxidised, whereas the H2O2 is reduced.

<span class="mw-page-title-main">Tebbe's reagent</span> Chemical compound

Tebbe's reagent is the organometallic compound with the formula (C5H5)2TiCH2ClAl(CH3)2. It is used in the methylidenation of carbonyl compounds, that is it converts organic compounds containing the R2C=O group into the related R2C=CH2 derivative. It is a red solid that is pyrophoric in the air, and thus is typically handled with air-free techniques. It was originally synthesized by Fred Tebbe at DuPont Central Research.

Pivalic acid is a carboxylic acid with a molecular formula of (CH3)3CCO2H. This colourless, odiferous organic compound is solid at room temperature. Two abbreviations for pivalic acid are t-BuC(O)OH and PivOH. The pivalyl or pivaloyl group is abbreviated t-BuC(O).

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

Trimethylsilyl trifluoromethanesulfonate (TMSOTf) is an organosilicon compound with the formula (CH3)3SiO3SCF3. It is a colorless moisture-sensitive liquid. It is the trifluoromethanesulfonate derivative of trimethylsilyl. It is mainly used to activate ketones and aldehydes in organic synthesis.

In organic chemistry, thiocarboxylic acids or carbothioic acids are organosulfur compounds related to carboxylic acids by replacement of one of the oxygen atoms with a sulfur atom. Two tautomers are possible: a thione form and a thiol form. These are sometimes also referred to as "carbothioic O-acid" and "carbothioic S-acid" respectively. Of these the thiol form is most common.

<i>tert</i>-Butyldimethylsilyl chloride Chemical compound

tert-Butyldimethylsilyl chloride is an organosilicon compound with the formula (Me3C)Me2SiCl (Me = CH3). It is commonly abbreviated as TBSCl or TBDMSCl. It is a chlorosilane containing two methyl groups and a tert-butyl group. As such it is more bulky that trimethylsilyl chloride. It is a colorless or white solid that is soluble in many organic solvents but reacts with water and alcohols. The compound is used to protect alcohols in organic synthesis.

<span class="mw-page-title-main">2,4-Lutidine</span> Chemical compound

2,4-Lutidine is a heterocyclic organic compound with the formula (CH3)2C5H3N. It is one of several dimethyl-substituted derivatives of pyridine, all of which are referred to as lutidines. It is a colorless liquid with mildly basic properties and a pungent, noxious odor. The compound has few uses.

<span class="mw-page-title-main">3,5-Lutidine</span> Chemical compound

3,5-Lutidine is a heterocyclic organic compound with the formula (CH3)2C5H3N. It is one of several dimethyl-substituted derivatives of pyridine, all of which are referred to as lutidines. It is a colorless liquid with mildly basic properties and a pungent odor. The compound is a precursor to the drug omeprazole.

Hydroxymethylation is a chemical reaction that installs the CH2OH group. The transformation can be implemented in many ways and applies to both industrial and biochemical processes.

References

  1. 1 2 The Merck Index: An Encyclopedia of Chemicals, Drugs, and Biologicals (11th ed.), Merck, 1989, ISBN   091191028X ,5485
  2. 1 2 3 Shimizu, Shinkichi; Watanabe, Nanao; Kataoka, Toshiaki; Shoji, Takayuki; Abe, Nobuyuki; Morishita, Sinji; Ichimura, Hisao (2007). "Pyridine and Pyridine Derivatives". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.a22_399. ISBN   978-3527306732.
  3. ↑ Singer, Alvin; McElvain, S. M. (1934). "2,6-Dimethylpyridine". Organic Syntheses. 14: 30. doi:10.15227/orgsyn.014.0030.
  4. ↑ Prudhomme, Daniel R.; Park, Minnie; Wang, Zhiwei; Buck, Jason R.; Rizzo, Carmelo J. (2000). "Synthesis of 2′-Deoxyribonucleosides: Β-3′,5′-Di-o-benzoylthymidine". Org. Synth. 77: 162. doi:10.15227/orgsyn.077.0162.
  5. ↑ Corey, E. J.; Cho, H.; Rücker, C.; Hua, D. H. (1981). "Studies with trialkylsilyltriflates: new syntheses and applications". Tetrahedron Letters. 22 (36): 3455–3458. doi:10.1016/s0040-4039(01)81930-4.
  6. ↑ Franck, Xavier; Figadère, Bruno; Cavé, André (1995). "Mild deprotection of tert-butyl and tert-amyl ethers leading either to alcohols or to trialkylsilyl ethers". Tetrahedron Letters. 36 (5): 711–714. doi:10.1016/0040-4039(94)02340-H. ISSN   0040-4039.
  7. ↑ Philipp, Bodo; Hoff, Malte; Germa, Florence; Schink, Bernhard; Beimborn, Dieter; Mersch-Sundermann, Volker (2007). "Biochemical Interpretation of Quantitative Structure-Activity Relationships (QSAR) for Biodegradation of N-Heterocycles: A Complementary Approach to Predict Biodegradability". Environmental Science & Technology. 41 (4): 1390–1398. Bibcode:2007EnST...41.1390P. doi:10.1021/es061505d. PMID   17593747.
  8. ↑ Sims, G. K.; Sommers, L. E. (1985). "Degradation of pyridine derivatives in soil". Journal of Environmental Quality. 14 (4): 580–584. Bibcode:1985JEnvQ..14..580S. doi:10.2134/jeq1985.00472425001400040022x.
  9. ↑ Sims, G. K.; Sommers, L. E. (1986). "Biodegradation of Pyridine Derivatives in Soil Suspensions". Environmental Toxicology and Chemistry. 5 (6): 503–509. doi:10.1002/etc.5620050601.
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