An exploratory study on the oxo-enol tautomerization of selected dioxopiperazines and their sulphur-containing analogues
| Autor: | Miklós Hollósi, Gyula Szókán, Ödön Farkas, András Perczel, Márton Kajtár |
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| Rok vydání: | 1993 |
| Předmět: |
animal structures
integumentary system Stereochemistry Keto–enol tautomerism Condensed Matter Physics Ring (chemistry) Biochemistry Enol Tautomer Bond length chemistry.chemical_compound Molecular geometry chemistry Ab initio quantum chemistry methods Molecule lipids (amino acids peptides and proteins) sense organs Physical and Theoretical Chemistry skin and connective tissue diseases |
| Zdroj: | Journal of Molecular Structure: THEOCHEM. 286:131-148 |
| ISSN: | 0166-1280 |
| Popis: | The ring structures of selected dioxopiperazines and their sulphur-containing analogues undergo remarkable geometry changes during enolization as established by semiempirical (AM1) and non-empirical (HF/3-21G) MO computations. The dienols attempt to lose their “pseudo-anti-aromatic” or “anti-aromatoid” character by three plausible mechanisms: (i) changing the CX bond length; (ii) changing the NH out-of-plane angle; (iii) changing the planarity/non-planarity of the six-membered ring. The effectiveness of these three mechanisms is discussed for cyclo(Gly-Gly), cyclo(Ala-Ala), cyclo(Pro-Pro) and their dithio derivatives cyclo(Gly t -Gly t , cyclo(Ala t -Ala t ), cyclo(Pro t -Pro t ). |
| Databáze: | OpenAIRE |
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