We found a match
Your institution may have rights to this item. Sign in to continue.
- Title
Incomparably easy migration of functionalized enol substituent in pyrrole ring.
- Authors
Sobenina, L. N.; Drichkov, V. N.; Petrova, O. V.; Ushakov, I. A.; Kashik, T. V.; Krivdin, L. B.; Rusakov, Yu. Yu.; Zykova, E. V.; Mikhaleva, A. I.; Trofimov, B. A.
- Abstract
Functionalized pyrroleьvьЄ enols, 2-(1-hydroxy-2.2-dicyanoethenyl)-1-methylpyrroles, at heating (75–135°C) unexpectedly readily rearranged in high yield into 3-isomers. Evidently the migration of the enol fragment involves a mesomeric zwitterion formed as a result of an intra- and intermolecular autoprotonation of the pyrrole ring by the acidic enol hydroxy group. Under similar conditions no migration of the ethenyl moiety occurred in 2-(1-hydroxy-2-carbamoyl-2-cyanoethenyl)-1-methylpyrroles. The quantum-chemical calculations (MP2/6-311G**) show a clear-cut distinction in the relative stability of 2- and 3-isomers of 1H- and 1-methylhydroxyethenylpyrroles: in the former case the 2-isomer is more stable, whereas in the 1-methyl-substituted compound, the 3-isomer.
- Subjects
ENOLS; PYRROLES; AZOLES; ORGANONITROGEN compounds; POLYZWITTERIONS; PROTON transfer reactions; ORGANIC chemistry
- Publication
Russian Journal of Organic Chemistry, 2008, Vol 44, Issue 2, p237
- ISSN
1070-4280
- Publication type
Article
- DOI
10.1134/S1070428008020097