{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,28]],"date-time":"2026-09-28T02:55:22Z","timestamp":1790564122153,"version":"4.1.0"},"reference-count":36,"publisher":"MDPI AG","issue":"21","license":[{"start":{"date-parts":[[2022,11,7]],"date-time":"2022-11-07T00:00:00Z","timestamp":1667779200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100006769","name":"Russian Scientific Foundation","doi-asserted-by":"publisher","award":["22-73-00098"],"award-info":[{"award-number":["22-73-00098"]}],"id":[{"id":"10.13039\/501100006769","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>Sterically shielded nitroxides, which demonstrate high resistance to bioreduction, are the spin labels of choice for structural studies inside living cells using pulsed EPR and functional MRI and EPRI in vivo. To prepare new sterically shielded nitroxides, a reaction of cyclic nitrones, including various 1-pyrroline-1-oxides, 2,5-dihydroimidazole-3-oxide and 4H-imidazole-3-oxide with alkynylmagnesium bromide wereused. The reaction gave corresponding nitroxides with an alkynyl group adjacent to the N-O moiety. The hydrogenation of resulting 2-ethynyl-substituted nitroxides with subsequent re-oxidation of the N-OH group produced the corresponding sterically shielded tetraalkylnitroxides of pyrrolidine, imidazolidine and 2,5-dihydroimidazole series. EPR studies revealed large additional couplings up to 4 G in the spectra of pyrrolidine and imidazolidine nitroxides with substituents in 3- and\/or 4-positions of the ring.<\/jats:p>","DOI":"10.3390\/molecules27217626","type":"journal-article","created":{"date-parts":[[2022,11,8]],"date-time":"2022-11-08T13:17:43Z","timestamp":1667913463000},"page":"7626","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":8,"title":["Synthesis of Sterically Shielded Nitroxides Using the Reaction of Nitrones with Alkynylmagnesium Bromides"],"prefix":"10.3390","volume":"27","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-3486-0335","authenticated-orcid":false,"given":"Sergey A.","family":"Dobrynin","sequence":"first","affiliation":[{"name":"N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, 630090 Novosibirsk, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mark M.","family":"Gulman","sequence":"additional","affiliation":[{"name":"N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, 630090 Novosibirsk, Russia"},{"name":"Department of Natural Sciences, Novosibirsk State University, Pirogova Str. 2, 630090 Novosibirsk, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2403-2843","authenticated-orcid":false,"given":"Denis A.","family":"Morozov","sequence":"additional","affiliation":[{"name":"N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, 630090 Novosibirsk, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8720-8768","authenticated-orcid":false,"given":"Irina F.","family":"Zhurko","sequence":"additional","affiliation":[{"name":"N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, 630090 Novosibirsk, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Andrey I.","family":"Taratayko","sequence":"additional","affiliation":[{"name":"N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, 630090 Novosibirsk, Russia"},{"name":"Department of Natural Sciences, Novosibirsk State University, Pirogova Str. 2, 630090 Novosibirsk, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yulia S.","family":"Sotnikova","sequence":"additional","affiliation":[{"name":"N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, 630090 Novosibirsk, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yurii I.","family":"Glazachev","sequence":"additional","affiliation":[{"name":"Voevodsky Institute of Chemical Kinetics and Combustion SB RAS, Institutskaya 3, 630090 Novosibirsk, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuri V.","family":"Gatilov","sequence":"additional","affiliation":[{"name":"N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, 630090 Novosibirsk, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6033-0368","authenticated-orcid":false,"given":"Igor A.","family":"Kirilyuk","sequence":"additional","affiliation":[{"name":"N. N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Lavrentiev Ave. 9, 630090 Novosibirsk, Russia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,11,7]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"78","DOI":"10.3109\/10715762.2014.979409","article-title":"Sterically shielded spin labels for in-cell EPR spectroscopy: Analysis of stability in reducing environment","volume":"49","author":"Jagtap","year":"2015","journal-title":"Free Rad. 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