Thermal rearrangement of spiro[naphthalene(naphthopyranofurazan)]oxides to spiro[naphthalene(phenalenofurazan)oxides. A probable furazan oxide triggered tandem isomerisation process
| dc.contributor.author | Supsana, P. | en |
| dc.contributor.author | Liaskopoulos, T. | en |
| dc.contributor.author | Skoulika, S. | en |
| dc.contributor.author | Kolocouris, A. | en |
| dc.contributor.author | Tsoungas, P. G. | en |
| dc.contributor.author | Varvounis, G. | en |
| dc.date.accessioned | 2015-11-24T16:51:28Z | |
| dc.date.available | 2015-11-24T16:51:28Z | |
| dc.identifier.issn | 0040-4020 | - |
| dc.identifier.uri | https://olympias.lib.uoi.gr/jspui/handle/123456789/9737 | |
| dc.rights | Default Licence | - |
| dc.subject | furazan oxides | en |
| dc.subject | spiro[naphthalene(phenalenofurazan)oxides | en |
| dc.subject | spiro compounds | en |
| dc.subject | thermal rearrangement | en |
| dc.subject | no-donor | en |
| dc.subject | heterocyclic rearrangements | en |
| dc.subject | photosensitive polyimide | en |
| dc.subject | orthosiphon-aristatus | en |
| dc.subject | sulfo groups | en |
| dc.subject | furoxans | en |
| dc.subject | benzofuroxans | en |
| dc.subject | derivatives | en |
| dc.subject | cyclization | en |
| dc.subject | oximes | en |
| dc.title | Thermal rearrangement of spiro[naphthalene(naphthopyranofurazan)]oxides to spiro[naphthalene(phenalenofurazan)oxides. A probable furazan oxide triggered tandem isomerisation process | en |
| heal.abstract | Thermal rearrangement of (+/-)-spiro {naphthalene-1(2H)4'-(naphtho-[2', 1': 2,3]pyrano[4,5-c]furazan)]-2-one-11'-oxides in DMF or acetic anhydride at 140 degrees C gave an isomeric mixture of (+/-)-spiro {naphthalene-1 (2H), 1'-(5'-hydroxyphenalene[1,2-c]furazan)}-2-one-2'-oxides and 4'-oxides. The rearranged structure was confirmed from X-ray analysis and was consistent with the through space NOE data. The rearrangement is suggested to be an overall tandem isomerization process. Using variable temperature H-1 NMR spectroscopy the lower limit for the isomerisation barrier for a pair of tautomers was calculated to be 22 kcal mol(-1) at 423 K. The isomerisation equilibrium for a pair of isomers was studied by variable temperature 1H NMR. The lower limit for the isomerisation barrier was calculated to be 22 kcal mol(-1) at 423 K. This low value may be indicative of the difficulty encountered in separating the isomers by chromatography. Semiempirical AMI and molecular mechanics calculations suggest that the (+/-)-spiro {naphthalene-1(2H), 1'-(5'-hydroxyphenalene[1,2-c]-furazan) 1-2-one-2'-oxides are more stable than their 4'-oxide counterparts, in accordance to the X-ray structure. The lower population of the 4'-oxide isomers relative to that of the 2'-oxide isomers was explained in terms of an unfavourable intramolecular steric interaction found in the low energy structure of the former. (c) 2005 Elsevier Ltd. All rights reserved. | en |
| heal.access | campus | - |
| heal.fullTextAvailability | TRUE | - |
| heal.identifier.primary | DOI 10.1016/j.tet.2005.03.068 | - |
| heal.identifier.secondary | <Go to ISI>://000229722000014 | - |
| heal.identifier.secondary | http://ac.els-cdn.com/S0040402005005077/1-s2.0-S0040402005005077-main.pdf?_tid=dcf57f9c-34ac-11e3-b0de-00000aab0f6c&acdnat=1381740459_e1bafe7a887e02992acfe83809a91108 | - |
| heal.journalName | Tetrahedron | en |
| heal.journalType | peer reviewed | - |
| heal.language | en | - |
| heal.publicationDate | 2005 | - |
| heal.publisher | Elsevier | en |
| heal.recordProvider | Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας | el |
| heal.type | journalArticle | - |
| heal.type.el | Άρθρο Περιοδικού | el |
| heal.type.en | Journal article | en |
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