Triazene derivatives of (1, x)-diazacycloalkanes. Part X. Synthesis and characterization of a series of 1,4-di[2-aryl-1-diazenyl]- trans -2,5-dimethylpiperazines

Vanessa Renee Little, Reid Tingley, Keith Vaughan

Research output: Contribution to journalArticleResearchpeer-review

Abstract

A series of 1,4-di[2-aryl-1-diazenyl]-trans-2,5-dimethylpiperazines(5a-5m), have been synthesized by the reaction of trans-2,5-dimethylpiperazine with two equivalents of the appropriate diazonium salt. The products have been characterized by IR and NMR spectroscopy, and the molecular composition has been verified by high-resolution EI mass spectrometry with accurate mass measurement of the molecular ion. The presence of stereocenters at C2 and C5 of the piperazine ring in the bis-triazene (5) creates two unique pairs of diastereotopic protons in the methylene groups at positions 3 and 6 of the piperazine ring, as evidenced by the complexity of the NMR spectra, which nevertheless can be fully assigned in some cases, such as the anisyl-(5i) and phenyl-(5j) derivatives. The assignment of the proton and carbon signals in the tolyl-derivative (5h) has been aided by the use of 2D NMR HSQC spectroscopy. These results compare favorably with assignments of proton and carbon signals reported previously for triazenes of type 1 and bis-triazenes of types 3 and 4b.

Original languageEnglish
Pages (from-to)665-669
Number of pages5
JournalCanadian Journal of Chemistry
Volume92
Issue number7
DOIs
Publication statusPublished - 22 May 2014
Externally publishedYes

Keywords

  • 2D NMR HSQC spectroscopy
  • Bis-triazenes
  • Diastereotopic relationships
  • Diazonium salts
  • Dimethylpiperazine
  • IR spectroscopy
  • Mass spectrometry
  • NMR spectroscopy
  • Piperazine
  • Triazene

Cite this

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title = "Triazene derivatives of (1, x)-diazacycloalkanes. Part X. Synthesis and characterization of a series of 1,4-di[2-aryl-1-diazenyl]- trans -2,5-dimethylpiperazines",
abstract = "A series of 1,4-di[2-aryl-1-diazenyl]-trans-2,5-dimethylpiperazines(5a-5m), have been synthesized by the reaction of trans-2,5-dimethylpiperazine with two equivalents of the appropriate diazonium salt. The products have been characterized by IR and NMR spectroscopy, and the molecular composition has been verified by high-resolution EI mass spectrometry with accurate mass measurement of the molecular ion. The presence of stereocenters at C2 and C5 of the piperazine ring in the bis-triazene (5) creates two unique pairs of diastereotopic protons in the methylene groups at positions 3 and 6 of the piperazine ring, as evidenced by the complexity of the NMR spectra, which nevertheless can be fully assigned in some cases, such as the anisyl-(5i) and phenyl-(5j) derivatives. The assignment of the proton and carbon signals in the tolyl-derivative (5h) has been aided by the use of 2D NMR HSQC spectroscopy. These results compare favorably with assignments of proton and carbon signals reported previously for triazenes of type 1 and bis-triazenes of types 3 and 4b.",
keywords = "2D NMR HSQC spectroscopy, Bis-triazenes, Diastereotopic relationships, Diazonium salts, Dimethylpiperazine, IR spectroscopy, Mass spectrometry, NMR spectroscopy, Piperazine, Triazene",
author = "Little, {Vanessa Renee} and Reid Tingley and Keith Vaughan",
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Triazene derivatives of (1, x)-diazacycloalkanes. Part X. Synthesis and characterization of a series of 1,4-di[2-aryl-1-diazenyl]- trans -2,5-dimethylpiperazines. / Little, Vanessa Renee; Tingley, Reid; Vaughan, Keith.

In: Canadian Journal of Chemistry, Vol. 92, No. 7, 22.05.2014, p. 665-669.

Research output: Contribution to journalArticleResearchpeer-review

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T1 - Triazene derivatives of (1, x)-diazacycloalkanes. Part X. Synthesis and characterization of a series of 1,4-di[2-aryl-1-diazenyl]- trans -2,5-dimethylpiperazines

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AU - Tingley, Reid

AU - Vaughan, Keith

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Y1 - 2014/5/22

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AB - A series of 1,4-di[2-aryl-1-diazenyl]-trans-2,5-dimethylpiperazines(5a-5m), have been synthesized by the reaction of trans-2,5-dimethylpiperazine with two equivalents of the appropriate diazonium salt. The products have been characterized by IR and NMR spectroscopy, and the molecular composition has been verified by high-resolution EI mass spectrometry with accurate mass measurement of the molecular ion. The presence of stereocenters at C2 and C5 of the piperazine ring in the bis-triazene (5) creates two unique pairs of diastereotopic protons in the methylene groups at positions 3 and 6 of the piperazine ring, as evidenced by the complexity of the NMR spectra, which nevertheless can be fully assigned in some cases, such as the anisyl-(5i) and phenyl-(5j) derivatives. The assignment of the proton and carbon signals in the tolyl-derivative (5h) has been aided by the use of 2D NMR HSQC spectroscopy. These results compare favorably with assignments of proton and carbon signals reported previously for triazenes of type 1 and bis-triazenes of types 3 and 4b.

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