579-18-0Relevant articles and documents
Erratum to: Design, characterization, computational studies and pharmacological evaluation of substituted-N′-[(1E) substituted- phenylmethylidene]benzohydrazide analogs (Medicinal Chemistry Research (2013) 22 (2755-2767) DOI:10.1007/s00044-012-0270-0)
Bala, Suman,Uppal, Goldie,Kamboj, Sunil,Saini, Vipin,Prasad
, p. 2698 - 2699 (2014/05/06)
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Application of complementary mass spectrometric techniques to the identification of ketoprofen phototransformation products
Kosjek, Tina,Perko, Silva,Heath, Ester,Kralj, Bogdan,Zigon, Dusan
experimental part, p. 391 - 401 (2011/11/12)
Ketoprofen (KP) is a nonsteroidal anti-inflammatory drug, which during UV irradiation rapidly transforms into benzophenone derivatives. Such transformation products may occur after topical application of KP, which is then exposed to sunlight resulting in a photo-allergic reaction. These reactions are mediated by the benzophenone moiety independently of the amount of allergen. The same reactions will also occur during wastewater or drinking water treatment albeit their effect in the aqueous environment is yet to be ascertained. In addition, only a few such transformation products have been recognised. To enable the detection and structural elucidation of the widest range of KP transformation products, this study applies complementary chromatographic and mass spectrometric techniques including gas chromatography coupled to single quadrupole or ion trap mass spectrometry and liquid chromatography hyphenated with quadrupole-time-of-flight mass spectrometry. Based on structural information gained in tandem and multiple MS experiments, and on highly accurate molecular mass measurements, chemical structures of 22 transformation products are proposed and used to construct an overall breakdown pathway. Among the identified transformation products all but two compounds retained the benzophenone moietya€"a result, which raises important issues concerning the possible toxic synergistic effects of KP and its transformation products. These findings trigger further research into water treatment technologies that would limit their entrance into environmental or drinking waters. Copyright
Chemistry and stereochemistry of benzyl-benzyl interactions in MH+ ions of dibenzyl esters upon chemical ionization and collision-induced dissociation conditions
Edelson-Averbukh,Mandelbaum
, p. 515 - 524 (2007/10/03)
Isobutane chemical ionization mass spectra of dibenzyl esters of a wide variety of aliphatic, olefinic, alicyclic and aromatic dicarboxylic acids exhibit abundant m/z 181 C14H13+ ions, indicating a highly general rearrangement process involving the formation of a new bond between the two benzyl groups. An extensive collision-induced dissociation and deuterium labeling study suggested that these ions are an almost equimolar mixture of isomeric α-o-tolylbenzyl, α-p-tolylbenzyl and p-benzylbenzyl cation structures, and this composition is identical for all the diesters examined. This structural assignment of the C14H13 ions suggests a mechanistic pathway for their generation, based on the formation of the new bond between the benzyl methylene group of the protonated benzoxycarbonyl and the phenyl ring of the other ester moiety via π- (and/or ion-neutral) and α-complexes. Stereoisomeric diesters show an unusual steric effect: trans-isomers give rise to much more abundant C14H13+ ions than the cis counterparts. This behavior is explained by stabilized proton-bridged structures of the MH+ ions of the cis-isomers.
