Photochemical Rearrangement of Aryl, Vinyl, and Substituted Vinyl Esters and Amides of Carboxylic Acids

Belluč, Daniel; Hrdlovič, Pavol

doi:10.1021/cr60250a001

Cited by 108 publications

(44 citation statements)

References 44 publications

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“…The precipitate was filtered off and the product was dried at 40 8C under vacuum and recrystallized from methanol to give pale yellow crystals with m. p. 174 8C, yield 62%. The prepared tetraacetyl compound (1.9 g, 3.5 mmol) was added to 211 mL of a 6 wt.-% Ba(OH) 2 solution, and was then shaken for 20 h. The solution was filtered and CO 2 Preparation of b-glucoside of phenyl salicylate (Glucoside III)…”

Section: Preparation Of Glucoside I (Gluco-p-oxybenzophenone)mentioning

confidence: 99%

“…Unfortunately, most of them turn yellow on exposure to UV light, and this limits their use as UV absorbers for colorless and transparent plastics. It is well known that the yellowing of these compounds is due to a photochemical rearrangement of the Fries type giving derivatives of dihydroxybenzophenones [2][3][4][5] . o-Hydroxybenzophenones are also long-known good photostabilizers.…”

Section: Introductionmentioning

confidence: 99%

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Glucoside derivatives as novel photostabilizers for rigid PVC

Braun

Richter

Rabie

et al. 1999

Angew. Makromol. Chem.

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Glucoside derivatives of some UV absorbers have been prepared and investigated as photostabilizers for PVC in absence and in presence of Ca‐Zn stearate. The results indicate a reasonable stabilizing effect of the glucosides compared with the parent UV absorbers. The prepared glucosides were also investigated as thermal stabilizers for PVC and exhibited good thermal stability compared with that of commercial Ca‐Zn stearate heat stabilizer.

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Section: Preparation Of Glucoside I (Gluco-p-oxybenzophenone)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Glucoside derivatives as novel photostabilizers for rigid PVC

Braun

Richter

Rabie

et al. 1999

Angew. Makromol. Chem.

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“…The photo-Fries reaction is fairly general for aromatic systems and usually leads to compounds derived from rearrangement of the initially formed biradicals to ortho and para products in a solvent cage. [7] The photo-Fries rearrangement is rather common with esters and amides and, as far as sulfur compounds are concerned, it has been observed with thiol esters [8] and sulfenanilides. [9] On the other hand, examples concerning aromatic disulfides are very rare; [10] it is also extremely unusual to encounter rearrangements exclusively affording ortho products.…”

Section: Resultsmentioning

confidence: 99%

On the Regioselectivity of Imidoyl Radical Cyclisations

Nanni¹,

Calestani

Leardini

et al. 2000

Eur. J. Org. Chem.

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The previously reported tandem cyclisation of N‐aryl α‐(2‐cyanophenyl)sulfanyl imidoyl radicals affords one quinoxaline derivative arising from exclusive 1,6‐cyclisation of the final iminyl radical onto the N‐aryl ring. When the imidoyl radicals are generated by addition of photolytically generated (2‐cyanophenyl)sulfanyl radicals to isocyanides, the reaction also gives small amounts of a by‐product that is formed by an analogous route and whose X‐ray crystallographic data are reported here. The formation of this product entails a rare ortho‐selective photo‐Fries rearrangement of the starting disulfide, followed by addition to the isocyanide and regioselective 1,5‐cyclisation of the resulting imidoyl onto only one of the two available radical acceptors, i.e. the cyano group and the sulfide moiety. Semiempirical MNDO‐d calculations were performed in order to throw some light on the factors affecting these competitive cyclisations.

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“…They proposed a free radical mechanism. Tahara [7] reported that long wavelength (780 nm) causes chain scission and short wavelength (240 nm) leads to crosslinking, whereas Bellus [8] suggested that during photodecomposition, the major reactions are rearrange- K 422 ments. Photo-aging with controlled variables, like the wavelength of light, oxygen or nitrogen atmosphere, presence of humidity and degree of prior hydrolysis was investigated by Pryde [9].…”

Section: Introductionmentioning

confidence: 99%

Photodegradation of poly(4,4?-isopropylidine diphenylene carbonate)

Gupta

Tahilyani

1988

Colloid & Polymer Sci

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The effect of UV radiation (253.7 nm) on poly(4,4'-isopropylidine diphenylene carbonate) in the presence of air has been studied by TG, UV and IR sprctroscopy and analytical methods. Thermal degradation in air is found to be a two-step process: oxidative degradation and oxidation and char formation of the crosslinked product, with activation energies of 125 and 230 kJ mol-1, respectively. UV, IR and analytical methods suggest that polycarbonate undergoes a photo-Fries process and salicylate, benzophenone and phenyl hydroxy terminal chains are produced. The results are consistent with a photo-aging mechanism in which side chain and ring photo-oxidation occur by the photoFries process, resulting in chain scission and the crosslinked reaction.

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Photochemical Rearrangement of Aryl, Vinyl, and Substituted Vinyl Esters and Amides of Carboxylic Acids

Cited by 108 publications

References 44 publications

Glucoside derivatives as novel photostabilizers for rigid PVC

Glucoside derivatives as novel photostabilizers for rigid PVC

On the Regioselectivity of Imidoyl Radical Cyclisations

Photodegradation of poly(4,4?-isopropylidine diphenylene carbonate)

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