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...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Beilstein-Institut
2014-04-01
|
| Series: | Beilstein Journal of Organic Chemistry |
| Subjects: | |
| Online Access: | https://doi.org/10.3762/bjoc.10.79 |
| id |
doaj-e27ac3cf27e9421ca90ac0ed33e8a36a |
|---|---|
| record_format |
Article |
| spelling |
doaj-e27ac3cf27e9421ca90ac0ed33e8a36a2021-02-02T00:12:41ZengBeilstein-InstitutBeilstein Journal of Organic Chemistry1860-53972014-04-0110183284010.3762/bjoc.10.791860-5397-10-79Dimerisation, rhodium complex formation and rearrangements of N-heterocyclic carbenes of indazolesZong Guan0Jan C. Namyslo1Martin H. H. Drafz2Martin Nieger3Andreas Schmidt4Clausthal University of Technology, Institute of Organic Chemistry, Leibnizstrasse 6, D-38678 Clausthal-Zellerfeld, GermanyClausthal University of Technology, Institute of Organic Chemistry, Leibnizstrasse 6, D-38678 Clausthal-Zellerfeld, GermanyClausthal University of Technology, Institute of Organic Chemistry, Leibnizstrasse 6, D-38678 Clausthal-Zellerfeld, GermanyUniversity of Helsinki, Laboratory of Inorganic Chemistry, Department of Chemistry, P.O. Box 55 (A.I. Virtasen aukio 1), FIN-00014 University of Helsinki, FinlandClausthal University of Technology, Institute of Organic Chemistry, Leibnizstrasse 6, D-38678 Clausthal-Zellerfeld, GermanyDeprotonation 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.https://doi.org/10.3762/bjoc.10.79E/Z isomerismindazol-3-ylidenemesomeric betainepyrazolequinazolineRh complex |
| collection |
DOAJ |
| language |
English |
| format |
Article |
| sources |
DOAJ |
| author |
Zong Guan Jan C. Namyslo Martin H. H. Drafz Martin Nieger Andreas Schmidt |
| spellingShingle |
Zong Guan Jan C. Namyslo Martin H. H. Drafz Martin Nieger Andreas Schmidt Dimerisation, rhodium complex formation and rearrangements of N-heterocyclic carbenes of indazoles Beilstein Journal of Organic Chemistry E/Z isomerism indazol-3-ylidene mesomeric betaine pyrazole quinazoline Rh complex |
| author_facet |
Zong Guan Jan C. Namyslo Martin H. H. Drafz Martin Nieger Andreas Schmidt |
| author_sort |
Zong Guan |
| title |
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_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_sort |
dimerisation, rhodium complex formation and rearrangements of n-heterocyclic carbenes of indazoles |
| publisher |
Beilstein-Institut |
| series |
Beilstein Journal of Organic Chemistry |
| issn |
1860-5397 |
| publishDate |
2014-04-01 |
| 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. |
| topic |
E/Z isomerism indazol-3-ylidene mesomeric betaine pyrazole quinazoline Rh complex |
| url |
https://doi.org/10.3762/bjoc.10.79 |
| work_keys_str_mv |
AT zongguan dimerisationrhodiumcomplexformationandrearrangementsofnheterocycliccarbenesofindazoles AT jancnamyslo dimerisationrhodiumcomplexformationandrearrangementsofnheterocycliccarbenesofindazoles AT martinhhdrafz dimerisationrhodiumcomplexformationandrearrangementsofnheterocycliccarbenesofindazoles AT martinnieger dimerisationrhodiumcomplexformationandrearrangementsofnheterocycliccarbenesofindazoles AT andreasschmidt dimerisationrhodiumcomplexformationandrearrangementsofnheterocycliccarbenesofindazoles |
| _version_ |
1724314331435237376 |