Isovaleraldehyde Explained

Isovaleraldehyde organic compound, also known as 3-methylbutanal, with the formula (CH₃)₂CHCH₂CHO. It is an aldehyde, a colorless liquid at STP,^[1] and found in low concentrations in many types of food.^[2] Commercially it is used as a reagent for the production of pharmaceuticals, perfumes and pesticides.

Synthesis

Synthetic routes for the production of isovaleraldehyde vary. One method is by the hydroformylation of isobutene:

A small amount of 2,2-dimethylpropanal (side product is also generated.

Another method of production involves the isomerization of 3-methylbut-3-en-1-ol using CuO–ZnO as a catalyst. A mixture of 3-methylbut-3-en-1-ol and 3-methylbut-2-en-1-ol may also be used. These starting materials are obtained from a reaction between isobutene and formaldehyde:

CH₃CH₃CCH₂ + CH₂O → (CH₃)₂CHCH₂CHO

Finally, in beer the compound is produced via a reaction between the amino acid leucine and reductones in the malt.^[3]

Occurrences and uses

As it can be derived from leucine, the occurrence of isovaleraldehyde is not limited to beer. The compound has found to be a flavor component in many different types of foods. It is described as having a malty flavor and has been found in cheese, coffee, chicken, fish, chocolate, olive oil, and tea.^[4] The compound is used as a reactant in the synthesis of a number of compounds. Notably it is used to synthesize 2,3-dimethylbut-2-ene, and is then converted to 2,3-dimethylbutane-2,3-diol and methyl tert-butyl ketone, better known as pinacolone. Pinacolone itself is then used in synthesis for number of pesticides. Additionally, a range of pharmaceuticals, such as butizide, are synthesized from isovaleraldehyde and its corresponding acid. It is a common reagent or building block in organic synthesis.^{[5] [6]}

Acid-catalyzed cyclic trimerization of Isovaleraldehyde gives 2,4,6-Triisobutyl-1,3,5-trioxane [68165-40-2]. This is a flavouring agent that can be used in confectionary, tobacco, and other foodstuffs, toothpastes and the like.^[7] It is described as imparting a creamy, dairy, vanilla chocolate and berry flavour.

According to IFF, isovaleraldehyde is used as a food flavorant additive.^[8]

Notes and References

1. Book: Lewis . R. J. Sr. . Hawley's Condensed Chemical Dictionary . 15th . John Wiley . New York, NY . 2007 . 719.
2. Encyclopedia: Cserháti . T. . Forgács . E. . Encyclopedia of Food Sciences and Nutrition . 2nd . Flavor (Flavour) Compounds: Structures and Characteristics . Elsevier Science . 2003 . 2509–2517.
3. Encyclopedia: Bamforth . C. W. . Encyclopedia of Food Sciences and Nutrition . 2nd . Chemistry of Brewing . 2003 . 440–447.
4. Encyclopedia: Owuor . P. O. . Encyclopedia of Food Sciences and Nutrition . 2nd . Tea: Analysis and Tasting . 2003 . 5757–5762.
5. 10.15227/orgsyn.092.0320. Organocatalyzed Direct Asymmetric α-Hydroxymethylation of Aldehydes . 2015 . Boeckman . Robert . Douglas J.. Tusch. Kyle F.. Biegasiewiczjournal=Organic Syntheses . 92 . 320–327 . free .
6. 10.15227/orgsyn.091.0175. Enantioselective Organocatalytic α-Arylation of Aldehydes . 2014 . Poulsen . Pernille . Mette. Overgaard. Kim L.. Jensen. Karl Anker. Jørgensenjournal=Organic Syntheses . 91 . 175–184 . free .
7. Donald Arthur Withycombe, et al., (1978 to International Flavors and Fragrances Inc).
8. http://lmrnaturals.iff.com/en/site-services/flavor-online-compendium-iframe#3-methylbutyraldehyde