ChemInform Abstract: SYNTHESIS OF 4‐PENTEN‐4‐OLIDES (Γ‐METHYLENE‐Γ‐BUTYROLACTONES) VIA 4‐PENTENOIC ACIDS

Guenther, Harald; Guntrum, Eberhard; Jaeger, V.

doi:10.1002/chin.198414182

Cited by 3 publications

(3 citation statements)

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“…Snider and Johnston investigated the halolactonizations of γ,δ-unsaturated acids and found that the reaction using NBS in a mixture of THF and acetic acid or bromine in methanol produces a mixture of γ-lactone and δ-lactone. 1760 There are a few other reagent combinations for the bromolactonization reaction using NBS, which include examples such as NBS/ AcOH−THF−H 2 O, 1761,1762 1765 Yeung has shown another catalytic bromolactonization of long-chain olefinic acids using NBS using a zwitterionic catalyst. 1766 This work resulted in an efficient synthetic route for medium-sized lactones.…”

Section: Use Of Nbs In Cyclization Reactionsmentioning

confidence: 99%

Use of Bromine and Bromo-Organic Compounds in Organic Synthesis

2016

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Bromination is one of the most important transformations in organic synthesis and can be carried out using bromine and many other bromo compounds. Use of molecular bromine in organic synthesis is well-known. However, due to the hazardous nature of bromine, enormous growth has been witnessed in the past several decades for the development of solid bromine carriers. This review outlines the use of bromine and different bromo-organic compounds in organic synthesis. The applications of bromine, a total of 107 bromo-organic compounds, 11 other brominating agents, and a few natural bromine sources were incorporated. The scope of these reagents for various organic transformations such as bromination, cohalogenation, oxidation, cyclization, ring-opening reactions, substitution, rearrangement, hydrolysis, catalysis, etc. has been described briefly to highlight important aspects of the bromo-organic compounds in organic synthesis.

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Section: Use Of Nbs In Cyclization Reactionsmentioning

confidence: 99%

Use of Bromine and Bromo-Organic Compounds in Organic Synthesis

2016

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“…Essentially, iodination of the acid gave 5-iodomethyl-dihydrofuran-2-one in excellent yield. Subsequent elimination with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) gave γ -angelicalactone in moderate yield (Gunther et al, 1984). 3-Methyl-5-methylene-dihydro-furan-2-one was obtained in excellent yield using the same method with 2-methylpenten-4-enoic acid as the starting material (Gunther et al, 1984).…”

Section: Synthesis Of Commercially Unavailable Chemicalsmentioning

confidence: 99%

Measurements of photo-oxidation products from the reaction of a series of alkyl-benzenes with hydroxyl radicals during EXACT using comprehensive gas chromatography

et al. 2003

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Abstract. Photo-oxidation products from the reaction of a series of alkyl-benzenes, (benzene, toluene, p-xylene and 1,3,5-trimethyl-benzene) with hydroxyl radicals in the presence of NO x have been investigated using comprehensive gas chromatography (GC×GC). A GC×GC system has been developed which utilises valve modulation and independent separations as a function of both volatility and polarity. A number of carbonyl-type compounds were identified during a series of reactions carried out at the European Photoreactor (EUPHORE), a large volume outdoor reaction chamber in Valencia, Spain. Experiments were carried as part of the EXACT project (Effects of the oXidation of Aromatic Compounds in the Troposphere). Two litre chamber air samples were cryo-focused, with a sampling frequency of 30 minutes, allowing the evolution of species to be followed over oxidation periods of 3-6 hours. To facilitate product identification, several carbonyl compounds, which were possible products of the photo-oxidation, were synthesised and used as reference standards.For toluene reactions, observed oxygenated intermediates found included the co-eluting pair α-angelicalactone/4-oxo-2-pentenal, maleic anhydride, citraconic anhydride, benzaldehyde and p-methyl benzoquinone. In the p-xylene experiment, the products identified were E/Z-hex-3-en-2,5-dione and citraconic anhydride. For 1,3,5-TMB reactions, the products identified were 3,5-dimethylbenzaldehyde, 3,5-dimethyl-3H-furan-2-one and 3-methyl-5-methylene-5H-furan-2-one. Preliminary quantification was carried out on identified compounds using liquid standards. Comparison of FTIR and GC×GC for the measurement of the parent aroCorrespondence to: J. F. Hamilton (jacquih@chemistry.leeds.ac.uk) matics generally showed good agreement. Comparison of the concentrations observed by GC×GC to concentrationtime profiles simulated using the Master Chemical Mechanism, MCMv3, demonstrates that this mechanism significantly over-predicts the concentrations of many product compounds and highlights the uncertainties which exist in our understanding of the atmospheric oxidation of aromatics.

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“…Essentially, iodination of the acid gave 5-iodomethyl-dihydrofuran-2-one in excellent yield. Subsequent elimination with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) gave γangelicalactone in moderate yield (Gunther et al, 1984). 3-Methyl-5-methylene-dihydro-furan-2-one was obtained in excellent yield using the same method with 2-methylpenten-4-enoic acid as the starting material (Gunther et al, 1984).…”

Section: Synthesis Of Commercially Unavailable Chemicalsmentioning

confidence: 99%

Measurements of photo-oxidation products from the reaction of a series of alkyl-benzenes with hydroxyl radicals during EXACT using comprehensive gas chromatography

Hamilton¹,

Lewis²,

Bloss³

et al. 2003

Preprint

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Abstract. Photo-oxidation products from the reaction of a series of alkyl-benzenes, (benzene, toluene, p-xylene and 1,3,5-trimethyl-benzene) with hydroxyl radicals in the presence of NOx have been investigated using comprehensive gas chromatography (GCXGC). A GCXGC system has been developed which utilises valve modulation and independent separations as a function of both volatility and polarity. A number of carbonyl-type compounds were identified during a series of reactions carried out at the European Photoreactor (EUPHORE), a large volume outdoor reaction chamber in Valencia, Spain. Two litre chamber air samples were cryo-focused, with a sampling frequency of 30 min, allowing the evolution of species to be followed over oxidation periods of 3–6 h. To facilitate product identification, several carbonyl compounds, which were possible products of the photo-oxidation, were synthesised and used as reference standards. For toluene reactions, observed oxygenated intermediates found included the co-eluting pair a-angelicalactone/4-oxo-2-pentenal, maleic anhydride, citraconic anhydride, benzaldehyde and p-methyl benzoquinone. In the p-xylene experiment, the products identified were E/Z-hex-3-en-2,5-dione and citraconic anhydride. For 1,3,5-TMB reactions, the products identified were 3,5-dimethylbenzaldehyde, 3,5-dimethyl-3H-furan-2-one and 3-methyl-5-methylene-5H-furan-2-one. Preliminary quantification was carried out on identified compounds using liquid standards. Comparison of FTIR and GCXGC for the measurement of the parent aromatics generally showed good agreement.

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ChemInform Abstract: SYNTHESIS OF 4‐PENTEN‐4‐OLIDES (Γ‐METHYLENE‐Γ‐BUTYROLACTONES) VIA 4‐PENTENOIC ACIDS

Abstract: Säurekatalysierte Kondensation der Allylalkohole (I) mit den Orthoestern (II) und Orthoester‐Umlagerung nach Claisen liefern Gemische der entsprechenden Pentensäureethyl‐ und ‐allylester, die ohne Isolierung zu" den Pentensäuren (III) verseift werden.

Cited by 3 publications

References 1 publication

Use of Bromine and Bromo-Organic Compounds in Organic Synthesis

Use of Bromine and Bromo-Organic Compounds in Organic Synthesis

Measurements of photo-oxidation products from the reaction of a series of alkyl-benzenes with hydroxyl radicals during EXACT using comprehensive gas chromatography

Measurements of photo-oxidation products from the reaction of a series of alkyl-benzenes with hydroxyl radicals during EXACT using comprehensive gas chromatography

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