Pinacol

Last updated
Pinacol
Pinacol-2D-skeletal.png
Pinacol-1-from-xtal-3D-bs-17.png
Names
Preferred IUPAC name
2,3-Dimethylbutane-2,3-diol
Other names
2,3-Dimethyl-2,3-butanediol
Tetramethylethylene glycol
1,1,2,2-Tetramethylethylene glycol
Pinacone
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.000.849 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 200-933-5
PubChem CID
UNII
  • InChI=1S/C6H14O2/c1-5(2,7)6(3,4)8/h7-8H,1-4H3 Yes check.svgY
    Key: IVDFJHOHABJVEH-UHFFFAOYSA-N Yes check.svgY
  • CC(C)(O)C(C)(C)O
  • CC(C)(O)C(C)(C)O
Properties
C6H14O2
Molar mass 118.174 g/mol
AppearanceWhite solid
Density 0.967 g/cm3
Melting point 40 to 43 °C (104 to 109 °F; 313 to 316 K)
Boiling point 171 to 173 °C (340 to 343 °F; 444 to 446 K)
Hazards
GHS labelling:
GHS-pictogram-acid.svg GHS-pictogram-exclam.svg
Warning
H228, H315, H319, H335
P210, P240, P241, P261, P264, P271, P280, P302+P352, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P370+P378, P403+P233, P405, P501
Flash point 77 °C (171 °F; 350 K)
Safety data sheet (SDS) External MSDS
Related compounds
Related compounds
Pinacolone
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Pinacol is a white solid organic compound. It is a diol that has hydroxyl groups (-OH) on vicinal carbon atoms.

Contents

Preparation

It may be produced by the pinacol coupling reaction from acetone: [1]

Pinacol coupling of acetone.png

Reactions

As a vicinal-diol, it can rearrange to pinacolone by the pinacol rearrangement, e.g. by heating with sulfuric acid: [2]

800px-Pinacol rearragement.png

Pinacol can be used with borane and boron trichloride to produce useful synthetic intermediates such as pinacolborane, bis(pinacolato)diboron, [3] and pinacolchloroborane.

See also

Related Research Articles

Sharpless asymmetric dihydroxylation is the chemical reaction of an alkene with osmium tetroxide in the presence of a chiral quinine ligand to form a vicinal diol. The reaction has been applied to alkenes of virtually every substitution, often high enantioselectivities are realized. Asymmetric dihydroxylation reactions are also highly site selective, providing products derived from reaction of the most electron-rich double bond in the substrate.

Oxime

An oxime is a chemical compound belonging to the imines, with the general formula RR'C=NOH, where R is an organic side-chain and R' may be hydrogen, forming an aldoxime, or another organic group, forming a ketoxime. O-substituted oximes form a closely related family of compounds. Amidoximes are oximes of amides with general structure R1C(=NOH)NR2R3.

A diol is a chemical compound containing two hydroxyl groups. An aliphatic diol is also called a glycol. This pairing of functional groups is pervasive, and many subcategories have been identified.

Sodium amide Chemical compound

Sodium amide, commonly called sodamide, is the inorganic compound with the formula NaNH2. It is a salt composed of the sodium cation and the azanide anion. This solid, which is dangerously reactive toward water, is white, but commercial samples are typically gray due to the presence of small quantities of metallic iron from the manufacturing process. Such impurities do not usually affect the utility of the reagent. NaNH2 conducts electricity in the fused state, its conductance being similar to that of NaOH in a similar state. NaNH2 has been widely employed as a strong base in organic synthesis.

Permanganate Chemical compound

A permanganate is the general name for a chemical compound containing the manganate(VII) ion, MnO
4
, the conjugate base of permanganic acid. Because the manganese atom is in the +7 oxidation state, the permanganate(VII) ion is a strong oxidizing agent. The ion has tetrahedral geometry. Permanganate solutions are purple in color and are stable in neutral or slightly alkaline media. The exact chemical reaction is dependent upon the organic contaminants present and the oxidant utilized. For example, trichloroethane (C2H3Cl3) is oxidized by permanganate ions to form carbon dioxide (CO2), manganese dioxide (MnO2), hydrogen ions (H+), and chloride ions (Cl).

<i>N</i>-Bromosuccinimide Molecule

N-Bromosuccinimide or NBS is a chemical reagent used in radical substitution, electrophilic addition, and electrophilic substitution reactions in organic chemistry. NBS can be a convenient source of Br, the bromine radical.

A pinacol coupling reaction is an organic reaction in which a carbon–carbon bond is formed between the carbonyl groups of an aldehyde or a ketone in presence of an electron donor in a free radical process. The reaction product is a vicinal diol. The reaction is named after pinacol, which is the product of this reaction when done with acetone as reagent. The reaction is usually a homocoupling but intramolecular cross-coupling reactions are also possible. Pinacol was discovered by Wilhelm Rudolph Fittig in 1859.

Favorskii rearrangement

The Favorskii rearrangement is principally a rearrangement of cyclopropanones and α-halo ketones that leads to carboxylic acid derivatives. In the case of cyclic α-halo ketones, the Favorskii rearrangement constitutes a ring contraction. This rearrangement takes place in the presence of a base, sometimes hydroxide, to yield a carboxylic acid but most of the time either an alkoxide base or an amine to yield an ester or an amide, respectively. α,α'-Dihaloketones eliminate HX under the reaction conditions to give α,β-unsaturated carbonyl compounds.

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.

The Bamberger rearrangement is the chemical reaction of phenylhydroxylamines with strong aqueous acid, which will rearrange to give 4-aminophenols. It is named for the German chemist Eugen Bamberger (1857–1932).

(Bis(trifluoroacetoxy)iodo)benzene Chemical compound

(Bis iodo)benzene, C
6
H
5
I(OCOCF
3
)
2
, is a hypervalent iodine compound used as a reagent in organic chemistry. It can be used to carry out the Hofmann rearrangement under acidic conditions.

Pinacol rearrangement

The pinacol–pinacolone rearrangement is a method for converting a 1,2-diol to a carbonyl compound in organic chemistry. The 1,2-rearrangement takes place under acidic conditions. The name of the rearrangement reaction comes from the rearrangement of pinacol to pinacolone.

Hexafluoroacetone Chemical compound

Hexafluoroacetone (HFA) is a chemical compound with the formula (CF3)2CO. It is structurally similar to acetone; however, its reactivity is markedly different. It a colourless, hygroscopic, nonflammable, highly reactive gas characterized by a musty odour. The most common form of this substance is hexafluoroacetone sesquihydrate (1.5 H2O), which is a hemihydrate of hexafluoropropane-2,2-diol (F
3
C)
2
C(OH)
2
, a geminal diol.

The semipinacol rearrangement is a rearrangement reaction in organic chemistry involving a heterosubstituted alcohol of the type R1R2(HO)C–C(X)R3R4. The hetero substituent can be a halogen (Cl, Br, I), a tosylate, a mesylate or a thiol group. This reaction proceeds by removal of the leaving group X forming a carbocation as electron deficient center. One of the adjacent alkyl groups then migrates to the positive carbon in a 1,2-shift. Simultaneously with the shift, a pi bond forms from the oxygen to carbon, assisting in driving the migrating group off its position. The result is a ketone or aldehyde. In another definition all semipinacol rearrangements "share a common reactive species in which an electrophilic carbon center, including but not limited to carbocations, is vicinal to an oxygen-containing carbon and can drive the 1,2-migration of a C–C or C–H bond to terminate the process, generating a carbonyl group ".

Boronic acid

A boronic acid is a compound related to boric acid in which one of the three hydroxyl groups is replaced by an alkyl or aryl group. As a compound containing a carbon–boron bond, members of this class thus belong to the larger class of organoboranes. Boronic acids act as Lewis acids. Their unique feature is that they are capable of forming reversible covalent complexes with sugars, amino acids, hydroxamic acids, etc.. The pKa of a boronic acid is ~9, but they can form tetrahedral boronate complexes with pKa ~7. They are occasionally used in the area of molecular recognition to bind to saccharides for fluorescent detection or selective transport of saccharides across membranes.

Pinacolone Chemical compound

Pinacolone (3,3-dimethyl-2-butanone) is an important ketone in organic chemistry. It is a colorless liquid and has a slight peppermint- or camphor- odor. It is a precursor to triazolylpinacolone in the synthesis of the fungicide triadimefon and in synthesis of the herbicide metribuzin. The molecule is an unsymmetrical ketone. The α-methyl group can participate in condensation reactions. The carbonyl group can undergo the usual reactions. It is a Schedule 3 compound under the Chemical Weapons Convention 1993, due to being related to pinacolyl alcohol, which is used in the production of soman. It is also a controlled export in Australia Group member states.

Bis(pinacolato)diboron Chemical compound

Bis(pinacolato)diboron is a covalent compound containing two boron atoms and two pinacolato ligands. It has the formula [(CH3)4C2O2B]2; the pinacol groups are sometimes abbreviated as "pin", so the structure is sometimes represented as B2pin2. It is a colourless solid that is soluble in organic solvents. It is a commercially available reagent for making pinacol boronic esters for organic synthesis. Unlike some other diboron compounds, B2pin2 is not moisture-sensitive and can be handled in air.

3,4-Dihydropyran (DHP) is a heterocyclic compound with the formula C5H8O. The six-membered C5O ring has the unsaturation adjacent to oxygen. The isomeric 3,6-dihydropyran has a methylene separating the double bond and oxygen. DHP is used for protecting group for alcohols. It is a colorless liquid.

An insertion reaction is a chemical reaction where one chemical entity interposes itself into an existing bond of typically a second chemical entity e.g.:

Miyaura borylation, also known as the Miyaura borylation reaction, is a named reaction in organic chemistry that allows for the generation of boronates from vinyl or aryl halides with the cross-coupling of bis(pinacolato)diboron in basic conditions with a catalyst such as PdCl2(dppf). The resulting borylated products can be used as coupling partners for the Suzuki reaction.

References

  1. Roger Adams and E. W. Adams. "Pinacol Hydrate". Organic Syntheses .; Collective Volume, vol. 1, p. 459
  2. G. A. Hill and E. W. Flosdorf (1941). "Pinacolone". Organic Syntheses .; Collective Volume, vol. 1, p. 462
  3. Tatsuo Ishiyama; Miki Murata; Taka-aki Ahiko; Norio Miyaura (2004). "Bis(pinacolato)diboron". Organic Syntheses .; Collective Volume, vol. 10, p. 115