Salicylaldehyde

Last updated
Salicylic aldehyde
Skeletal formula Salicylaldehyde.svg
Skeletal formula
Ball-and-stick model Salicylaldehyde-3D-balls-B.png
Ball-and-stick model
Names
Preferred IUPAC name
2-Hydroxybenzaldehyde [1]
Other names
Salicylaldehyde
Salicylic aldehyde
o-Hydroxybenzaldehyde
Identifiers
3D model (JSmol)
471388
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.001.783 OOjs UI icon edit-ltr-progressive.svg
EC Number
  • 201-961-0
3273
KEGG
PubChem CID
UNII
  • InChI=1S/C7H6O2/c8-5-6-3-1-2-4-7(6)9/h1-5,9H Yes check.svgY
    Key: SMQUZDBALVYZAC-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/C7H6O2/c8-5-6-3-1-2-4-7(6)9/h1-5,9H
    Key: SMQUZDBALVYZAC-UHFFFAOYAD
  • O=Cc1ccccc1O
Properties
C7H6O2
Molar mass 122.123 g·mol−1
Density 1.146 g/cm3
Melting point −7 °C (19 °F; 266 K)
Boiling point 196 to 197 °C (385 to 387 °F; 469 to 470 K)
-64.4·10−6 cm3/mol
Hazards [2]
GHS labelling:
GHS-pictogram-exclam.svg GHS-pictogram-pollu.svg
Warning
H302, H315, H317, H319, H335, H411
P280, P305+P351+P338
Safety data sheet (SDS) [2]
Related compounds
Related compounds
 Salicylic acid
Benzaldehyde
Salicylaldoxime
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Yes check.svgY  verify  (what is  Yes check.svgYX mark.svgN ?)

Salicylic aldehyde (2-hydroxybenzaldehyde) is an organic compound with the formula C6H4OH(CHO). [3] [4] Along with 3-hydroxybenzaldehyde and 4-hydroxybenzaldehyde, it is one of the three isomers of hydroxybenzaldehyde. This colorless oily liquid has a bitter almond odor at higher concentration. Salicylaldehyde is a precursor to coumarin and a variety of chelating agents.

Contents

Production

Salicylaldehyde is produced by condensation of phenol with formaldehyde to give hydroxybenzyl alcohol, which is oxidized to the aldehyde. [4] Salicylaldehydes in general are prepared by ortho-selective formylation reactions from the corresponding phenol, for instance by the Duff reaction, Reimer–Tiemann reaction, or by treatment with paraformaldehyde in the presence of magnesium chloride and a base. [5] [6]

Reimer-Tiemann Reaction Scheme.png

Natural occurrences

Salicylaldehyde is a characteristic aroma component of buckwheat. [7] Salicylaldehyde also occurs in the larval defensive secretions of several leaf beetle species that belong the subtribe Chrysomelina. [8] An example for a leaf beetle species that produces salicylaldehyde is the red poplar leaf beetle Chrysomela populi .

Reactions and applications

Salicylaldehyde is mainly used commercially as a precursor to coumarin. The conversion entails condensation with acetic anhydride ("Perkin synthesis"). [4]

Catechol, benzofuran, a salicylaldehydimine (R = alkyl or aryl), 3-carbethoxycoumarin Salicylaldehyde Derivatives.svg
Catechol, benzofuran, a salicylaldehydimine (R = alkyl or aryl), 3-carbethoxycoumarin
  1. Oxidation with hydrogen peroxide gives catechol (1,2-dihydroxybenzene) (Dakin reaction). [9]
  2. Etherification with chloroacetic acid followed by cyclisation gives the heterocycle benzofuran (coumarone). [10] The first step in this reaction to the substituted benzofuran is called the Rap–Stoermer condensation after E. Rap (1895) and R. Stoermer (1900). [11] [12]
  3. Salicylaldehyde is converted to chelating ligands by condensation with amines. With ethylenediamine, it condenses to give the ligand salen. Hydroxylamine gives salicylaldoxime.
  4. Condensation with diethyl malonate gives 3-carbethoxycoumarin (a derivative of coumarin) by an aldol condensation. [13]

Internal hydrogen bonding

Due to the ortho positioning of the hydroxy- and aldehyde groups, an internal hydrogen bond is formed between the groups. The hydroxy group serves here as the hydrogen bond donor, and the aldehyde as hydrogen bond acceptor. This internal hydrogen is not found in the other hydroxybenzaldehyde isomers. When the aldehyde is reacted with an amine to form an imine, the internal hydrogen bond is even stronger. [14] In addition, tautomerisation further increases the stability of the compound. [15] The internal hydrogen bond also ensures that the aldehyde (or corresponding imine) is held into the same plane, making the whole molecule essentially flat. [16]

Related Research Articles

<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">Benzofuran</span> Heterocyclic compound consisting of fused benzene and furan rings

Benzofuran is the heterocyclic compound consisting of fused benzene and furan rings. This colourless liquid is a component of coal tar. Benzofuran is the structural nucleus of many related compounds with more complex structures. For example, psoralen is a benzofuran derivative that occurs in several plants.

In organic chemistry, the Knoevenagel condensation reaction is a type of chemical reaction named after German chemist Emil Knoevenagel. It is a modification of the aldol condensation.

The Vilsmeier–Haack reaction (also called the Vilsmeier reaction) is the chemical reaction of a substituted formamide (1) with phosphorus oxychloride and an electron-rich arene (3) to produce an aryl aldehyde or ketone (5):

The Duff reaction or hexamine aromatic formylation is a formylation reaction used in organic chemistry for the synthesis of benzaldehydes with hexamine as the formyl carbon source. The method is generally inefficient. The reaction is named after James Cooper Duff.

<span class="mw-page-title-main">Iminium</span> Polyatomic ion of the form >C=N< and charge +1

In organic chemistry, an iminium cation is a polyatomic ion with the general structure [R1R2C=NR3R4]+. They are common in synthetic chemistry and biology.

<i>o</i>-Phenylenediamine Chemical compound

o-Phenylenediamine (OPD) is an organic compound with the formula C6H4(NH2)2. This aromatic diamine is an important precursor to many heterocyclic compounds. OPD is a white compound although samples appear darker owing to oxidation by air. It is isomeric with m-phenylenediamine and p-phenylenediamine.

<span class="mw-page-title-main">Reimer–Tiemann reaction</span> Chemical reaction for ortho-formylation of phenols

The Reimer–Tiemann reaction is a chemical reaction used for the ortho-formylation of phenols. with the simplest example being the conversion of phenol to salicylaldehyde. The reaction was first reported by Karl Reimer and Ferdinand Tiemann.

<span class="mw-page-title-main">1,4-Benzoquinone</span> Chemical compound

1,4-Benzoquinone, commonly known as para-quinone, is a chemical compound with the formula C6H4O2. In a pure state, it forms bright-yellow crystals with a characteristic irritating odor, resembling that of chlorine, bleach, and hot plastic or formaldehyde. This six-membered ring compound is the oxidized derivative of 1,4-hydroquinone. The molecule is multifunctional: it exhibits properties of a ketone, being able to form oximes; an oxidant, forming the dihydroxy derivative; and an alkene, undergoing addition reactions, especially those typical for α,β-unsaturated ketones. 1,4-Benzoquinone is sensitive toward both strong mineral acids and alkali, which cause condensation and decomposition of the compound.

<span class="mw-page-title-main">Carbonyl condensation</span> Organic reaction of carbonyl compounds with amines to imines

In organic chemistry, alkylimino-de-oxo-bisubstitution is the organic reaction of carbonyl compounds with amines to imines. The reaction name is based on the IUPAC Nomenclature for Transformations. The reaction is acid catalyzed and the reaction type is nucleophilic addition of the amine to the carbonyl compound followed by transfer of a proton from nitrogen to oxygen to a stable hemiaminal or carbinolamine. With primary amines, water is lost in an elimination reaction to an imine. With aryl amines, especially stable Schiff bases are formed.

<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.

The Gattermann reaction (also known as the Gattermann formylation and the Gattermann salicylaldehyde synthesis) is a chemical reaction in which aromatic compounds are formylated by a mixture of hydrogen cyanide (HCN) and hydrogen chloride (HCl) in the presence of a Lewis acid catalyst such as aluminium chloride (AlCl3). It is named for the German chemist Ludwig Gattermann and is similar to the Friedel–Crafts reaction.

The Hoesch reaction or Houben–Hoesch reaction is an organic reaction in which a nitrile reacts with an arene compound to form an aryl ketone. The reaction is a type of Friedel-Crafts acylation with hydrogen chloride and a Lewis acid catalyst.

In nitrile reduction a nitrile is reduced to either an amine or an aldehyde with a suitable chemical reagent.

Amide reduction is a reaction in organic synthesis where an amide is reduced to either an amine or an aldehyde functional group.

Rieche formylation is a type of formylation reaction. The substrates are electron rich aromatic compounds, such as mesitylene or phenols, with dichloromethyl methyl ether acting as the formyl source. The catalyst is titanium tetrachloride and the workup is acidic. The reaction is named after Alfred Rieche who discovered it in 1960.

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

Propionaldehyde or propanal is the organic compound with the formula CH3CH2CHO. It is the 3-carbon aldehyde. It is a colourless, flammable liquid with a pungent and fruity odour. It is produced on a large scale industrially.

<span class="mw-page-title-main">Imidoyl chloride</span>

Imidoyl chlorides are organic compounds that contain the functional group RC(NR')Cl. A double bond exist between the R'N and the carbon centre. These compounds are analogues of acyl chloride. Imidoyl chlorides tend to be highly reactive and are more commonly found as intermediates in a wide variety of synthetic procedures. Such procedures include Gattermann aldehyde synthesis, Houben-Hoesch ketone synthesis, and the Beckmann rearrangement. Their chemistry is related to that of enamines and their tautomers when the α hydrogen is next to the C=N bond. Many chlorinated N-heterocycles are formally imidoyl chlorides, e.g. 2-chloropyridine, 2, 4, and 6-chloropyrimidines.

<span class="mw-page-title-main">Anthracene-9-carbaldehyde</span> Chemical compound

Anthracene-9-carbaldehyde is the most common monoaldehyde derivative of anthracene. It is a yellow solid that is soluble in common organic solvents. It is prepared by Vilsmeier formylation of anthracene. The compound is also used as a building block for supramolecular assemblies. Hydrogenation of 9-anthracenecarboxaldehyde gives 9-anthracenemethanol.

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. ↑ "Front Matter". Nomenclature of Organic Chemistry : IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 652. doi:10.1039/9781849733069-FP001. ISBN   978-0-85404-182-4.
  2. 1 2 Sigma-Aldrich Co., Salicylaldehyde. Retrieved on 2018-05-24.
  3. ↑ Merck Index, 11th Edition, 8295
  4. 1 2 3 Maliverney, Christian; Mulhauser, Michel (2000). "Hydroxybenzaldehydes". Kirk-Othmer Encyclopedia of Chemical Technology. doi:10.1002/0471238961.0825041813011209.a01. ISBN   978-0-471-48494-3.
  5. ↑ Trond Vidar Hansen; Lars Skattebøl (2005). "Ortho-Formylation of Phenols; Preparation of 3-Bromosalicylaldehyde". Organic Syntheses . 82: 64. doi:10.15227/orgsyn.089.0220 .
  6. ↑ Brühne, F.; Wright, E. "Benzaldehyde". Ullmann's Encyclopedia of Industrial Chemistry . Weinheim: Wiley-VCH. doi:10.1002/14356007.a03_463.pub2. ISBN   978-3527306732.{{cite encyclopedia}}: CS1 maint: multiple names: authors list (link)
  7. ↑ Janeš, D.; Kreft, S. (2008). "Salicylaldehyde is a characteristic aroma component of buckwheat groats". Food Chemistry . 109 (2): 293–298. doi:10.1016/j.foodchem.2007.12.032. PMID   26003350.
  8. ↑ Pauls, G., Becker, T., et al. (2016). Two Defensive Lines in Juvenile Leaf Beetles; Esters of 3-nitropropionic Acid in the Hemolymph and Aposematic Warning. Journal of Chemical Ecology 42 (3) 240-248.
  9. ↑ Dakin, H. D. (1923). "Catechol" (PDF). Organic Syntheses . 3: 28; Collected Volumes, vol. 1, p. 149.
  10. ↑ Burgstahler, A. W.; Worden, L. R. (1966). "Coumarone". Organic Syntheses . 46: 28. doi:10.15227/orgsyn.046.0028 {{cite journal}}: CS1 maint: multiple names: authors list (link).
  11. ↑ Rap, E. (November 1895). "Sull' α-Benzoilcumarone" [On the α-Benzoylcoumaron]. Gazzetta Chimica Italiana . 2 (4): 285–290.
  12. ↑ Stoermer, R. (1900). "Synthesen und Abbaureactionen in der Cumaronreihe". Liebig's Annalen der Chemie . 312 (3): 237–336. doi:10.1002/jlac.19003120302.
  13. ↑ Horning, E. C.; Horning, M. G.; Dimmig, D. A. (1948). "3-Carbethoxycoumarin". Organic Syntheses . 28: 24. doi:10.15227/orgsyn.028.0024 {{cite journal}}: CS1 maint: multiple names: authors list (link).
  14. ↑ Schoustra, S.K.; Asadi, V.; Zuilhof, H.; Smulders, M.M.J. (2023). "Internal hydrogen bonding of imines to control and enhance the dynamic mechanical properties of covalent adaptable networks". European Polymer Journal . 195: 112209. doi: 10.1016/j.eurpolymj.2023.112209 .
  15. ↑ Metzler, C.M.; Cahill, A.; Metzler, D.E. (1980). "Equilibriums and absorption spectra of Schiff bases". J. Am. Chem. Soc. 102 (19): 6075–6082. doi:10.1021/ja00539a017.
  16. ↑ Kandambeth, S.; Shinde, D.B; Panda, M.K.; Lukose, B.; Heine, T.; Banerjee, R. (2013). "Enhancement of Chemical Stability and Crystallinity in Porphyrin-Containing Covalent Organic Frameworks by Intramolecular Hydrogen Bonds". Angew. Chem. Int. Ed. 52 (49): 13052–13056. doi: 10.1002/anie.201306775 .
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