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Dimerisation, rhodium complex formation and rearrangements of N-heterocyclic carbenes of indazoles
Deprotonation of indazolium salts at low temperatures gives N-heterocyclic carbenes of indazoles (indazol-3-ylidenes) which can be trapped as rhodium complexes (X-ray analysis). In the absence of Rh, the indazol-3-ylidenes spontaneously dimerize under ring cleavage of one of the N,N-bonds and ring c...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Beilstein-Institut
2014
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3999838/ https://www.ncbi.nlm.nih.gov/pubmed/24778738 http://dx.doi.org/10.3762/bjoc.10.79 |
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author | Guan, Zong Namyslo, Jan C Drafz, Martin H H Nieger, Martin Schmidt, Andreas |
author_facet | Guan, Zong Namyslo, Jan C Drafz, Martin H H Nieger, Martin Schmidt, Andreas |
author_sort | Guan, Zong |
collection | PubMed |
description | Deprotonation of indazolium salts at low temperatures gives N-heterocyclic carbenes of indazoles (indazol-3-ylidenes) which can be trapped as rhodium complexes (X-ray analysis). In the absence of Rh, the indazol-3-ylidenes spontaneously dimerize under ring cleavage of one of the N,N-bonds and ring closure to an indazole–indole spiro compound which possesses an exocyclic imine group. The E/Z isomers of the imines can be separated by column chromatography when methanol is used as eluent. We present results of a single crystal X-ray analysis of one of the E-isomers, which equilibrate in solution as well as in the solid state. Heating of the indazole–indole spiro compounds results in the formation of quinazolines by a ring-cleavage/ring-closure sequence (X-ray analysis). Results of DFT calculations are presented. |
format | Online Article Text |
id | pubmed-3999838 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2014 |
publisher | Beilstein-Institut |
record_format | MEDLINE/PubMed |
spelling | pubmed-39998382014-04-28 Dimerisation, rhodium complex formation and rearrangements of N-heterocyclic carbenes of indazoles Guan, Zong Namyslo, Jan C Drafz, Martin H H Nieger, Martin Schmidt, Andreas Beilstein J Org Chem Full Research Paper Deprotonation of indazolium salts at low temperatures gives N-heterocyclic carbenes of indazoles (indazol-3-ylidenes) which can be trapped as rhodium complexes (X-ray analysis). In the absence of Rh, the indazol-3-ylidenes spontaneously dimerize under ring cleavage of one of the N,N-bonds and ring closure to an indazole–indole spiro compound which possesses an exocyclic imine group. The E/Z isomers of the imines can be separated by column chromatography when methanol is used as eluent. We present results of a single crystal X-ray analysis of one of the E-isomers, which equilibrate in solution as well as in the solid state. Heating of the indazole–indole spiro compounds results in the formation of quinazolines by a ring-cleavage/ring-closure sequence (X-ray analysis). Results of DFT calculations are presented. Beilstein-Institut 2014-04-10 /pmc/articles/PMC3999838/ /pubmed/24778738 http://dx.doi.org/10.3762/bjoc.10.79 Text en Copyright © 2014, Guan et al. https://creativecommons.org/licenses/by/2.0https://www.beilstein-journals.org/bjoc/termsThis is an Open Access article under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The license is subject to the Beilstein Journal of Organic Chemistry terms and conditions: (https://www.beilstein-journals.org/bjoc/terms) |
spellingShingle | Full Research Paper Guan, Zong Namyslo, Jan C Drafz, Martin H H Nieger, Martin Schmidt, Andreas Dimerisation, rhodium complex formation and rearrangements of N-heterocyclic carbenes of indazoles |
title | Dimerisation, rhodium complex formation and rearrangements of N-heterocyclic carbenes of indazoles |
title_full | Dimerisation, rhodium complex formation and rearrangements of N-heterocyclic carbenes of indazoles |
title_fullStr | Dimerisation, rhodium complex formation and rearrangements of N-heterocyclic carbenes of indazoles |
title_full_unstemmed | Dimerisation, rhodium complex formation and rearrangements of N-heterocyclic carbenes of indazoles |
title_short | Dimerisation, rhodium complex formation and rearrangements of N-heterocyclic carbenes of indazoles |
title_sort | dimerisation, rhodium complex formation and rearrangements of n-heterocyclic carbenes of indazoles |
topic | Full Research Paper |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3999838/ https://www.ncbi.nlm.nih.gov/pubmed/24778738 http://dx.doi.org/10.3762/bjoc.10.79 |
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