Theoretical and experimental studies on ring closure reactions of 4(5)-chloro-5(4)-hydroxyalkylamino-6-nitro-3 (2H)-pyridazinones

Olivér Éliás, László Károlyházy, G. Stájer, F. Fülöp, Klára Czakó, Veronika Harmath, Orsolya Barabás, Katalin Keseru, P. Mátyus

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Cyclization of the title compounds with sodium ethoxide may proceed in various ways to afford differently fused pyridazino ring systems. Theoretical considerations based on frontier molecular orbital (FMO) analysis of 4-chloro-5-hydroxyalkylamino-6-nitropyridazinones were in agreement with experimental results in most cases. Formation of pyridazino[3,4] annelated systems was predicted and observed from 5-hydroxyethylamines and their N-benzyl analogs. However, in the ring closure reaction of the 5-N-benzyl-N-hydroxypropylamino derivative, besides [3,4] annelation, another cyclization also occurred to form a pyridazino[4,5-b]oxazepine derivative as minor product, whereas the 5-hydroxypropylamino derivative without an N-benzyl group gave a [3,4]-fused bicyclic compound, and a 6-ethoxy monocyclic derivative. The next homologue, i.e. the 5-hydroxybutylamino derivative, underwent only an intermolecular nucleophilic substitution reaction to give 6-ethoxypyridazinone derivative. In the cases of the 4-regioisomers, the N-benzyl derivatives could only be cyclized, and pyridazino[4,5] annelated systems were obtained. Structures of new compounds were proven by spectroscopic methods and microanalytical data. For a regioisomeric pair of pyridazino[4,5-b]oxazepines, X-ray analyzes were also carried out.

Original languageEnglish
Pages (from-to)75-96
Number of pages22
JournalJournal of Molecular Structure: THEOCHEM
Volume545
DOIs
Publication statusPublished - Jul 9 2001

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Oxazepines
Cyclization
closures
Theoretical Models
Derivatives
rings
molecular orbitals
sodium
X-Rays
substitutes
analogs
products
x rays
Molecular orbitals
Substitution reactions
Sodium
X rays

Keywords

  • Ab initio method
  • AM1 method
  • FMO theory
  • Pyridazino[3,4]- and pyridazino[4,5]-ring systems
  • X-ray analysis

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Computational Theory and Mathematics
  • Atomic and Molecular Physics, and Optics

Cite this

Theoretical and experimental studies on ring closure reactions of 4(5)-chloro-5(4)-hydroxyalkylamino-6-nitro-3 (2H)-pyridazinones. / Éliás, Olivér; Károlyházy, László; Stájer, G.; Fülöp, F.; Czakó, Klára; Harmath, Veronika; Barabás, Orsolya; Keseru, Katalin; Mátyus, P.

In: Journal of Molecular Structure: THEOCHEM, Vol. 545, 09.07.2001, p. 75-96.

Research output: Contribution to journalArticle

Éliás, Olivér ; Károlyházy, László ; Stájer, G. ; Fülöp, F. ; Czakó, Klára ; Harmath, Veronika ; Barabás, Orsolya ; Keseru, Katalin ; Mátyus, P. / Theoretical and experimental studies on ring closure reactions of 4(5)-chloro-5(4)-hydroxyalkylamino-6-nitro-3 (2H)-pyridazinones. In: Journal of Molecular Structure: THEOCHEM. 2001 ; Vol. 545. pp. 75-96.
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abstract = "Cyclization of the title compounds with sodium ethoxide may proceed in various ways to afford differently fused pyridazino ring systems. Theoretical considerations based on frontier molecular orbital (FMO) analysis of 4-chloro-5-hydroxyalkylamino-6-nitropyridazinones were in agreement with experimental results in most cases. Formation of pyridazino[3,4] annelated systems was predicted and observed from 5-hydroxyethylamines and their N-benzyl analogs. However, in the ring closure reaction of the 5-N-benzyl-N-hydroxypropylamino derivative, besides [3,4] annelation, another cyclization also occurred to form a pyridazino[4,5-b]oxazepine derivative as minor product, whereas the 5-hydroxypropylamino derivative without an N-benzyl group gave a [3,4]-fused bicyclic compound, and a 6-ethoxy monocyclic derivative. The next homologue, i.e. the 5-hydroxybutylamino derivative, underwent only an intermolecular nucleophilic substitution reaction to give 6-ethoxypyridazinone derivative. In the cases of the 4-regioisomers, the N-benzyl derivatives could only be cyclized, and pyridazino[4,5] annelated systems were obtained. Structures of new compounds were proven by spectroscopic methods and microanalytical data. For a regioisomeric pair of pyridazino[4,5-b]oxazepines, X-ray analyzes were also carried out.",
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T1 - Theoretical and experimental studies on ring closure reactions of 4(5)-chloro-5(4)-hydroxyalkylamino-6-nitro-3 (2H)-pyridazinones

AU - Éliás, Olivér

AU - Károlyházy, László

AU - Stájer, G.

AU - Fülöp, F.

AU - Czakó, Klára

AU - Harmath, Veronika

AU - Barabás, Orsolya

AU - Keseru, Katalin

AU - Mátyus, P.

PY - 2001/7/9

Y1 - 2001/7/9

N2 - Cyclization of the title compounds with sodium ethoxide may proceed in various ways to afford differently fused pyridazino ring systems. Theoretical considerations based on frontier molecular orbital (FMO) analysis of 4-chloro-5-hydroxyalkylamino-6-nitropyridazinones were in agreement with experimental results in most cases. Formation of pyridazino[3,4] annelated systems was predicted and observed from 5-hydroxyethylamines and their N-benzyl analogs. However, in the ring closure reaction of the 5-N-benzyl-N-hydroxypropylamino derivative, besides [3,4] annelation, another cyclization also occurred to form a pyridazino[4,5-b]oxazepine derivative as minor product, whereas the 5-hydroxypropylamino derivative without an N-benzyl group gave a [3,4]-fused bicyclic compound, and a 6-ethoxy monocyclic derivative. The next homologue, i.e. the 5-hydroxybutylamino derivative, underwent only an intermolecular nucleophilic substitution reaction to give 6-ethoxypyridazinone derivative. In the cases of the 4-regioisomers, the N-benzyl derivatives could only be cyclized, and pyridazino[4,5] annelated systems were obtained. Structures of new compounds were proven by spectroscopic methods and microanalytical data. For a regioisomeric pair of pyridazino[4,5-b]oxazepines, X-ray analyzes were also carried out.

AB - Cyclization of the title compounds with sodium ethoxide may proceed in various ways to afford differently fused pyridazino ring systems. Theoretical considerations based on frontier molecular orbital (FMO) analysis of 4-chloro-5-hydroxyalkylamino-6-nitropyridazinones were in agreement with experimental results in most cases. Formation of pyridazino[3,4] annelated systems was predicted and observed from 5-hydroxyethylamines and their N-benzyl analogs. However, in the ring closure reaction of the 5-N-benzyl-N-hydroxypropylamino derivative, besides [3,4] annelation, another cyclization also occurred to form a pyridazino[4,5-b]oxazepine derivative as minor product, whereas the 5-hydroxypropylamino derivative without an N-benzyl group gave a [3,4]-fused bicyclic compound, and a 6-ethoxy monocyclic derivative. The next homologue, i.e. the 5-hydroxybutylamino derivative, underwent only an intermolecular nucleophilic substitution reaction to give 6-ethoxypyridazinone derivative. In the cases of the 4-regioisomers, the N-benzyl derivatives could only be cyclized, and pyridazino[4,5] annelated systems were obtained. Structures of new compounds were proven by spectroscopic methods and microanalytical data. For a regioisomeric pair of pyridazino[4,5-b]oxazepines, X-ray analyzes were also carried out.

KW - Ab initio method

KW - AM1 method

KW - FMO theory

KW - Pyridazino[3,4]- and pyridazino[4,5]-ring systems

KW - X-ray analysis

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