Acid-catalysed epimerization of indolo[2,3-a]quinolizidine derivatives: Role of the nitrogen lone pairs in the mechanism
| Autor: | Arto Tolvanen, Martin Brunner, Mauri Lounasmaa, Harri Suomalainen, Mathias Berner |
|---|---|
| Rok vydání: | 1998 |
| Předmět: |
Quinolizidine
010405 organic chemistry Stereochemistry Organic Chemistry chemistry.chemical_element biochemical phenomena metabolism and nutrition 010402 general chemistry 01 natural sciences Biochemistry Nitrogen Quinolizidines 3. Good health 0104 chemical sciences chemistry.chemical_compound chemistry Drug Discovery polycyclic compounds Lactam Trifluoroacetic acid Epimer Lone pair |
| Zdroj: | Tetrahedron. 54:10205-10216 |
| ISSN: | 0040-4020 |
| Popis: | The role of the nitrogen lone pairs in the mechanism of the acid-catalysed epimerization of indolo[2,3- a ]quinolizidines is investigated using lactams as model compounds. Deethyleburnamonine ( 3 ) did not epimerize with trifluoroacetic acid (TFA), whereas deethyldihydroeburnamenine ( 7 ) underwent epimerization smoothly. Under treatment with TFA, lactams 12 and 13 both epimerized with ease to a mixture of lactams 12 and 13 . An analogous equilibrium was achieved when the experiment was repeated with lactams 18 and 19 . Intermediate 20 was trapped (Zn reduction) in the acid-catalysed epimerization of lactam 12 , allowing conclusions about the mechanism. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect