The mechanism of the norrish type II reaction of α-keto-acids and esters

Davidson, R. S.; Goodwin, Dean; Violet, Philippe Fornier de

doi:10.1016/s0040-4039(01)92939-9

Cited by 17 publications

(10 citation statements)

References 4 publications

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Section: Results and Discussionsupporting

confidence: 92%

“…Our observations are in line with previous spectroscopic investigations on related compounds indicating that pyruvates are not likely to undergo type I α-cleavage reactions but rather react via triplet-state hydrogen transfer. 22,35,36 Hydrogels. Hydrogels are an important class of materials, especially in the field of tissue regeneration.…”

Section: Macromoleculesmentioning

confidence: 99%

“…In 1981, Davidson et al published a paper on the investigation of the Norrish type II reaction of long chain aliphatic α-ketoesters and -acids. They were able to show that intramolecular hydrogen abstraction leads to a biradical intermediate which further decomposes to alkenes and a pyruvate (Scheme a).…”

Section: Introductionmentioning

confidence: 99%

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α-Ketoesters as Nonaromatic Photoinitiators for Radical Polymerization of (Meth)acrylates

et al. 2019

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Photopolymerization of (meth)acrylate-based formulations has become a widespread method for industry due to the high energy efficiency and low curing times of this technology. Various products from simple coatings to more complex applications such as additive manufacturing technologies are based on this versatile method. Common industrial radical photoinitiators are generally based on aromatic ketones with the benzoyl chromophore as the key constituent. In medical or food packaging applications, residual photoinitiator or photoproducts migrating into the product have to be avoided, particularly for toxicological reasons. In this paper we present a new generation of nonaromatic initiator systems. Besides their good reactivity in (meth)acrylic formulations, they show good bleaching properties and high biocompatibility.

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Section: Results and Discussionsupporting

confidence: 92%

Section: Macromoleculesmentioning

confidence: 99%

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α-Ketoesters as Nonaromatic Photoinitiators for Radical Polymerization of (Meth)acrylates

et al. 2019

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“…α‐Ketoesters, ethyl pyruvate for example, are sensitive to UV‐light with an absorption maximum at around 330 nm (n‐π*). However, the molar extinction coefficient of α‐ketoesters is much lower compared to aromatic ring containing photoinitiators, the quantum yield as well as the radical reactivity is much higher …”

Section: Introductionmentioning

confidence: 99%

Biocompatible photoinitiators based on poly‐α‐ketoesters

Taschner

Gauss

Knaack

et al. 2020

Journal of Polymer Science

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Migration of photoinitiators and their photoproducts are a major problem when it comes to food packaging or applications in the medical sector. Frequent coincidence with leachables and humans can be problematic, especially over time. Therefore, a new class of biocompatible photoinitiators, the aliphatic α‐ketoesters, were selected to be immobilized. Biocompatibility and low leaching were achieved using the metabolite α‐ketoglutaric acid. Immobilization of the photoinitiator is obtained via a macromolecular or copolymerizable approach.

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“…The photoinduced dehalogenation of aromatic halocompounds by amine is well known and the generally suggested mechanism is that the radical anions produced via the exciplexes of singlet halocompounds with ground-state amines are the reaction intermediates which decompose into the aryl radicals and the halogen anions (Ohashi et al 1973;Tsujimoto et al 1975;Bunce et al 1976Bunce et al , 1978Chittin et al 1978;Davidson and Goodwin 1981;Fulara and Latowski 1990;Saeva 1990). Upon investigation of the photochemical debromination of meso-substituted bromoanthracenes (9,10-dibromo and 9-bromo compounds) by amine [triethylamine (TEA) or N,N-dimethylaniline (DMA)] in acetonitrile, we have also concluded that the reaction intermediates are the bromoanthracene radical anions produced by a diffusion-controlled reaction of the lowest excited singlet states of bromoanthracenes with the ground-state amines yielding singlet exciplexes followed by decomposition into bromoanthracene radical anions and amine radical cations (Hamanoue et al 1984b).…”

Section: Introductionmentioning

confidence: 99%

Amine-assisted photochemical dehalogenation of haloanthracenes (9-halo and 9,10-dihalo compounds) and their triplet formation

1993

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Steady-state photolysis of haloanthracenes (XA; 9,10-dichloro, 9,10-dibromo, 9-chloro and 9-bromo compounds) in acetonitrile-amine (triethylamine or N,N-dimethylaniline) causes the consecutive reactions; 9,10-dihaio compounds-*9-halo compounds-, anthracene. Although both the lowest excited singlet [~XA(S1)] and triplet [3XA(T1)] states of XA are quenched by amine, the appearance of absorption spectra due to the haloanthracene radical anions (XA"-) within the duration of nanosecond pulse excitation indicates that the intermediates for dehalogenation of XA are XA"-produced by a diffusion-controlled reaction of 1XA(SI) with the ground-state amine yielding the singlet exciplexes [l(XA-amine)*] which decompose rapidly into XA'-and the amine radical cations. Moreover, an amine-assisted formation of 3XA(T~) has been attributed to the intersystem crossing from l(XA-amine)* to the triplet exciplexes [3(XA-amine)*] followed by decomposition into 3XA(Tt) and ground-state amine. Keywords. Photochemical dehalogenation of haloanthracenes by amines; amine-assisted triplet formation of haloanthracenes; haloanthracene radical anions; 9,10-dihaio and 9-halo anthracenes.

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The mechanism of the norrish type II reaction of α-keto-acids and esters

Cited by 17 publications

References 4 publications

α-Ketoesters as Nonaromatic Photoinitiators for Radical Polymerization of (Meth)acrylates

α-Ketoesters as Nonaromatic Photoinitiators for Radical Polymerization of (Meth)acrylates

Biocompatible photoinitiators based on poly‐α‐ketoesters

Amine-assisted photochemical dehalogenation of haloanthracenes (9-halo and 9,10-dihalo compounds) and their triplet formation

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