{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,12]],"date-time":"2026-02-12T10:43:27Z","timestamp":1770893007542,"version":"3.50.1"},"reference-count":20,"publisher":"Wiley","issue":"24","license":[{"start":{"date-parts":[[2023,10,31]],"date-time":"2023-10-31T00:00:00Z","timestamp":1698710400000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":["analyticalsciencejournals.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Rapid Comm Mass Spectrometry"],"published-print":{"date-parts":[[2023,12,30]]},"abstract":"\n Rationale<\/jats:title>\n \n Product ion studies and stable isotope deuterium labeling experiments provide useful data for understanding the electron ionization (EI)\u2010mass spectroscopy (MS) fragmentation of methoxymethylene substituted benzoate esters. The methoxymethylene ether is regioisomeric with the ethoxy group and represents the two possible ether substituents of a benzene ring of C\n 2<\/jats:sub>\n H\n 5<\/jats:sub>\n O. Structural confirmation of these synthetic precursor materials via gas chromatography (GC)\n \u2013<\/jats:bold>\n EI\u2010MS revealed unexpected fragment ions. The synthesis and EI\u2010MS evaluation of some homologs and deuterated derivatives allowed for the characterization of these unique ions and their fragmentation pathways. The relative effects of the position of the oxygen of the ether side chain are the subject of this investigation.\n <\/jats:p>\n <\/jats:sec>\n \n Methods<\/jats:title>\n The desired compounds were prepared from 4\u2010chloromethylbenzoyl chloride by alkoxide displacement followed by transesterifications and the deuterated analogs were prepared similarly. The compounds were separated by capillary GC and their MS fragmentation evaluated in EI, MS\/MS and chemical ionization experiments.<\/jats:p>\n <\/jats:sec>\n \n Results<\/jats:title>\n \n The methoxymethylene\u2010substituted benzoate esters yield major fragment ions from the loss of the alkyl group from the ether as well as alkoxy group loss from the ester or ether portion of the molecule. The loss of the alkyl group from the ether followed by loss of the ester alkoxy group as the corresponding alcohol yielded the unique cation at\n m\/z<\/jats:italic>\n 133 for all compounds. The identity of the major ions was confirmed by product ion and deuterium labeling studies and possible mechanisms of fragment ion formation are described.\n <\/jats:p>\n <\/jats:sec>\n \n Conclusions<\/jats:title>\n \n The aliphatic oxygen of the alkoxymethylene group plays a much more active role in the EI\u2010MS fragment formation profile than the direct aromatic ring linked oxygen of the ethoxy group. Thus, yielding a greater variety of characteristic fragments. The\n m\/z<\/jats:italic>\n 133 ion is unique to this class of compounds and does not have an equivalent pathway for the regioisomeric ethoxy series.\n <\/jats:p>\n <\/jats:sec>","DOI":"10.1002\/rcm.9654","type":"journal-article","created":{"date-parts":[[2023,10,31]],"date-time":"2023-10-31T08:52:09Z","timestamp":1698742329000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":3,"title":["Electron ionization fragmentation studies for a series of 4\u2010methoxymethylene benzoate esters"],"prefix":"10.1002","volume":"37","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2694-7561","authenticated-orcid":false,"given":"Younis","family":"Abiedalla","sequence":"first","affiliation":[{"name":"Department of Drug Discovery and Development, Harrison College of Pharmacy Auburn University Auburn Alabama USA"},{"name":"Department of Medicinal Chemistry, Faculty of Pharmacy Omar Al\u2010Mukhtar University El\u2010Beida Al Bayda' Libya"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4063-605X","authenticated-orcid":false,"given":"C. Randall","family":"Clark","sequence":"additional","affiliation":[{"name":"Department of Drug Discovery and Development, Harrison College of Pharmacy Auburn University Auburn Alabama USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2023,10,31]]},"reference":[{"key":"e_1_2_6_2_1","doi-asserted-by":"publisher","DOI":"10.1002\/rcm.8593"},{"key":"e_1_2_6_3_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.talanta.2017.04.067"},{"key":"e_1_2_6_4_1","doi-asserted-by":"publisher","DOI":"10.1021\/ac500316x"},{"key":"e_1_2_6_5_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.forc.2021.100314"},{"key":"e_1_2_6_6_1","doi-asserted-by":"publisher","DOI":"10.1255\/ejms.1185"},{"key":"e_1_2_6_7_1","doi-asserted-by":"publisher","DOI":"10.1007\/s11419\u2010015\u20100270\u20100"},{"key":"e_1_2_6_8_1","volume-title":"PiHKAL: A chemical love story","author":"Shulgin A","year":"1991"},{"key":"e_1_2_6_9_1","doi-asserted-by":"publisher","DOI":"10.1016\/s0091\u20103057(97)00323\u20107"},{"key":"e_1_2_6_10_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.forc.2019.100164"},{"key":"e_1_2_6_11_1","doi-asserted-by":"publisher","DOI":"10.1093\/chromsci\/bms031"},{"key":"e_1_2_6_12_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.forsciint.2010.03.033"},{"key":"e_1_2_6_13_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.forsciint.2008.12.003"},{"key":"e_1_2_6_14_1","doi-asserted-by":"publisher","DOI":"10.1093\/chromsci\/46.8.671"},{"key":"e_1_2_6_15_1","doi-asserted-by":"publisher","DOI":"10.18434\/T4D303"},{"key":"e_1_2_6_16_1","unstructured":"McLaffertyFW TurecekF.Interpretation of mass spectra.4th edition(1993).University Science Books (Pages138\u2013140)."},{"key":"e_1_2_6_17_1","doi-asserted-by":"publisher","DOI":"10.1002\/dta.1417"},{"key":"e_1_2_6_18_1","doi-asserted-by":"publisher","DOI":"10.1002\/rcm.7603"},{"key":"e_1_2_6_19_1","doi-asserted-by":"publisher","DOI":"10.1093\/chromsci\/bmw159"},{"key":"e_1_2_6_20_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.forc.2020.100245"},{"key":"e_1_2_6_21_1","doi-asserted-by":"publisher","DOI":"10.1002\/rcm.7171"}],"container-title":["Rapid Communications in Mass Spectrometry"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/analyticalsciencejournals.onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/rcm.9654","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,26]],"date-time":"2025-10-26T12:44:51Z","timestamp":1761482691000},"score":1,"resource":{"primary":{"URL":"https:\/\/analyticalsciencejournals.onlinelibrary.wiley.com\/doi\/10.1002\/rcm.9654"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,10,31]]},"references-count":20,"journal-issue":{"issue":"24","published-print":{"date-parts":[[2023,12,30]]}},"alternative-id":["10.1002\/rcm.9654"],"URL":"https:\/\/doi.org\/10.1002\/rcm.9654","archive":["Portico"],"relation":{},"ISSN":["0951-4198","1097-0231"],"issn-type":[{"value":"0951-4198","type":"print"},{"value":"1097-0231","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,10,31]]},"assertion":[{"value":"2023-07-06","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2023-10-02","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2023-10-31","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}],"article-number":"e9654"}}