- Mass spectrometric characterization of organosulfates related to secondary organic aerosol from isoprene
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Rationale: A considerable fraction of atmospheric particulate fine matter consists of organosulfates, with some of the most polar ones originating from the oxidation of isoprene. Their structural characterization provides insights into the nature of gas-phase precursors as well as into formation pathways. Methods: The structures of unknown polar organosulfates present in ambient particulate fine matter were characterized using liquid chromatography/(-) electrospray ionization mass spectrometry (LC/(-)ESI-MS), including ion trap MSn and accurate mass measurements, derivatization of the carbonyl group into 2,4-dinitrophenylhydrazones, detailed interpretation of the MS data, and in a selected case comparison of their LC and MS behavior with that of synthesized reference compounds. Results: Polar organosulfates with molecular weights (MWs) of 156, 170, 184 and 200 were attributed to/or confirmed as derivatives of glycolic acid (156), lactic acid (170), 1,2-dihydroxy-3-butanone (184), glycolic acid glycolate (200), 2-methylglyceric acid (200), and 2,3-dihydroxybutanoic acid (200). In the case of the MW 184 compound an unambiguous assignment was obtained through synthesis of reference compounds. Conclusions: A more complete structural characterization of polar organosulfates that originate from isoprene secondary organic aerosol was achieved. An important atmospheric finding is the presence of an organosulfate that is related to methyl vinyl ketone, a major gas-phase oxidation product of isoprene. In addition, minor polar organosulfates related to crotonaldehyde were identified. Copyright
- Safi Shalamzari, Mohammad,Ryabtsova, Oxana,Kahnt, Ariane,Vermeylen, Reinhilde,Hérent, Marie-France,Quetin-Leclercq, Jo?lle,Van Der Veken, Pieter,Maenhaut, Willy,Claeys, Magda
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- Acetalization of α,β-unsaturated carbonyl compounds catalyzed by complexes of Pt(II)
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A class of cationic diphosphine complexes of Pt(II) are sufficiently Lewis acidic to catalyze the acetalization of aldehydes and ketones. α,β-Unsaturated substrates can be easily acetalized with ethylene glycol under mild conditions in high yield and avoiding side reactions leading to formation of undesired by-products arising from the nucleophilic addition to the carbon-carbon double bond conjugated to the carbonyl group. A comparison of the behavior of a Pt complex with respect to PTSA as catalysts under identical conditions shows the superior selectivity of the former in many cases.
- Nieddu, Enrico,Cataldo, Maurizio,Pinna, Francesco,Strukul, Giorgio
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- Practical synthesis of functionalized terminal alkynes, 3,3,3-triethoxypropyne and ketal protected prop-2-ynones
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Practical and economical synthesis of synthetically valuable 3,3,3-triethoxypropyne, ketal protected phenyl and methyl substituents prop-2-ynones is described. Bromination and subsequent 18-crown-6 catalyzed elimination of triethylorthoacrylate and ketal
- Karanfil, Abdullah,Eskici, Mustafa
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supporting information
p. 2342 - 2351
(2017/12/12)
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- The effects of ring size and substituents on the rates of acid-catalysed hydrolysis of five- and six-membered ring cyclic ketone acetals
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A series of sterically similar five- and six-membered ring cyclic diol-derived ketone acetals have been prepared and their rates of acid-catalysed hydrolysis examined. The rates of hydrolysis are substantially affected by acetal ring conformational stereoelectronic effects and resonance effects depending upon the substituents on the parent ketone; an A1 mechanism of hydrolysis explains the observed effects. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
- Knowles, Jonathan P.,Whiting, Andrew
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p. 3365 - 3368
(2008/02/10)
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- Synthesis of phosphono analogues of dihydroxyacetone phosphate and glyceraldehyde 3-phosphate
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The present paper describes the synthetic routes of six phosphono analogues of dihydroxyacetone phosphate and five phosphono analogues of glyceraldehyde 3-phosphate through α-, β- and γ-hydroxyphosphonate esters precursors containing a protected carbonyl
- Page, Patrick,Blonski, Casimir,Perie, Jacques
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p. 1403 - 1412
(2007/10/03)
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- Palladium-Catalyzed Three Carbon Chain Extension Reactions with Acrolein Acetals. A Convenient Synthesis of Conjugated Dienals
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A variety of vinylic halides has been found to react with acrolein or methacrolein acetals and amines with palladium catalysts to form 5-amino 3-enal acetals and/or dienal acetals.The reaction products yield 2,4-dienals on treatment with aqueous acids, in moderate to good yields.Crotonaldehyde dimethyl acetal also undergoes the reaction, but only in low yields. 3-Buten-2-one ethylene ketal reacted well under the same conditions, however, and Hofmann elimination and hydrolysis of the product amine gave (E,E)-3,5-heptadien-2-one in 90percent yield.
- Patel, Babu A.,Kim, Jin-Il I.,Bender, Diana D.,Kao, Lien-Chung,Heck, Richard F.
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p. 1061 - 1067
(2007/10/02)
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