The keto-enol tautomerism and the redox conversions of α-ketol fatty acids

Grechkin, Alexander N.; Kuramshin, R. A.; Safonova, E.Y.; Mukhtarova, Lucia S.; Latypov, Shamil K.; Il'yasov, A. V.

doi:10.1016/0009-3084(93)90006-o

Cited by 7 publications

(2 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

Section: Unsaturated Fas With the Double Bond At The βγ-Positionmentioning

confidence: 99%

“…Thus, when the aliphatic double bond is lost, e.g., after epoxidation, the product loses its UV absorbance between 200 and 240 nm. Since oxo-fatty acids are subject to keto-enol tautomerism, they tend to attenuate or even lose their UV spectrum when the equilibrium is shifted toward the oxo-form [30]. It should be noted that the percentage conversions refer to the total amount of products formed (i.e., roughly the substrate converted); therefore, high percentages of the products may not correspond to large total amounts of product.…”

Section: Unsaturated Fas With the Double Bond At The βγ-Positionmentioning

confidence: 99%

See 1 more Smart Citation

Conversion of Unsaturated Short- to Medium-Chain Fatty Acids by Unspecific Peroxygenases (UPOs)

Karich,

Salzsieder,

Kluge

et al. 2023

Applied Microbiology

View full text Add to dashboard Cite

Eighteen short- to medium-chain monounsaturated fatty acids were screened for hydroxylation and epoxidation using eleven different peroxygenase preparations. Most of these unspecific peroxygenases (UPOs) are secreted by fungal species of the dark-spored basidiomycetous families Psathyrellaceae and Strophariaceae, two belonged to the white-spored genus Marasmius (Marasmiaceae), and one belonged to the ascomycetous family Chaetomiaceae. The fatty acids (FAs) studied were categorized into three groups based on the position of the double bond: (i) terminal unsaturated FAs (between ω and ω-1), (ii) α-β-unsaturated FAs (between C2 and C3), and (iii) β-γ-unsaturated FAs (between C3 and C4). Their chain lengths ranged from three to nine carbon atoms. FAs with a terminal double bond were significantly oxidized by only two UPOs, namely CglUPO and CraUPO (peroxygenases from Chaetomium globosum and Coprinellus radians, respectively), producing different products. FAs with internal double bonds were converted by all tested UPOs. While epoxides were observed as products in the case of α-β-unsaturated fatty acids, only CglUPO formed β-γ-epoxides from the corresponding FAs. The product pattern of the other UPOs for β-γ-unsaturated FAs was quite similar. On the other hand, the product pattern for oxidized α-β-unsaturated FAs was more variable and, in some cases, specific to a particular UPO. For example, in the reaction with trans-2-nonenoic acid, the enzymes clustered into six groups based on the formed products.

show abstract

Section: Unsaturated Fas With the Double Bond At The βγ-Positionmentioning

confidence: 99%

Section: Unsaturated Fas With the Double Bond At The βγ-Positionmentioning

confidence: 99%

Conversion of Unsaturated Short- to Medium-Chain Fatty Acids by Unspecific Peroxygenases (UPOs)

Karich,

Salzsieder,

Kluge

et al. 2023

Applied Microbiology

View full text Add to dashboard Cite

show abstract

Peroxyl Radicals in Synthesis

Boukouvalas¹,

Haynes²

2001

Radicals in Organic Synthesis

View full text Add to dashboard Cite

This chapter covers organic compounds prepared via intermediates which are alkyl peroxyl radicals (ROO') generated either by addition of ground state (triplet) oxygen to carbon-centered radicals, or by hydrogen atom abstraction from the corresponding hydroperoxides (ROOH). While some earlier work is briefly mentioned, the focus is primarily on new developments, published over the past decade or so. The emphasis is heavily on synthetic applications rather than physical, biological and environmental aspects of peroxyl radical chemistry. A book exclusively devoted to the latter topics has recently been published [l]. Some preparatively relevant pathways involving peroxyl radicals have been previously discussed in the context of reviews on the oxidation of organic molecules [2-41 and the synthesis of organic peroxides [5][6][7][8]. The present survey is clearly distinguished in scope; it is intended to cover a more diverse array of peroxyl radical pathways and to highlight recent applications in the field of natural product synthesis. The aim is to alert not only the peroxide specialist, but also the synthetic chemist in general, since the first-formed peroxidic products can be used as relay intermediates in the synthesis of nonperoxidic compounds. Autoxidation of HydrocarbonsThe oxidation of hydrocarbons and other organic molecules with oxygen or air is usually referred to as autoxidation [4, 7a, 91. This entirely atom-economical process (Eq. 1, Scheme 1) is ca. 18-24 kcal/mol exothermic and irreversible at temperatures below 250°C. Although the initiation step (Eq. 2) is not well understood [2, lo], it is clear that a chain radical process is involved, with addition of molecular oxygen to R as the initial propagation step (Eq. 3 ) . At oxygen pressures above 100 mm Hg, the reaction of R' with 0 2 proceeds with rate constants approaching the diffusioncontrol limit [7a, 9a]. The second propagation step involves hydrogen atom abstrac- Radicals in Organic Synthesis Edited

show abstract

Clavulones and related tert-hydroxycyclopentenone fatty acids: occurrence, physiological activity and problem of biogenetic origin

Grechkin

1995

Journal of Lipid Mediators and Cell Signalling

View full text Add to dashboard Cite

The keto-enol tautomerism and the redox conversions of α-ketol fatty acids

Cited by 7 publications

References 17 publications

Conversion of Unsaturated Short- to Medium-Chain Fatty Acids by Unspecific Peroxygenases (UPOs)

Conversion of Unsaturated Short- to Medium-Chain Fatty Acids by Unspecific Peroxygenases (UPOs)

Peroxyl Radicals in Synthesis

Clavulones and related tert-hydroxycyclopentenone fatty acids: occurrence, physiological activity and problem of biogenetic origin

Contact Info

Product

Resources

About