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 language | English |
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Pages (from-to) | 665-669 |
Number of pages | 5 |
Journal | Canadian Journal of Chemistry |
Volume | 92 |
Issue number | 7 |
DOIs | |
Publication status | Published - 22 May 2014 |
Externally published | Yes |
Keywords
- 2D NMR HSQC spectroscopy
- Bis-triazenes
- Diastereotopic relationships
- Diazonium salts
- Dimethylpiperazine
- IR spectroscopy
- Mass spectrometry
- NMR spectroscopy
- Piperazine
- Triazene