Diazocinones: Synthesis and conformational analysis

Lori I. Robins, Richard D. Carpenter, James C. Fettinger, Makhluf J. Haddadin, Dino S. Tinti, Mark J. Kurth

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

1,2,4,5-Tetrazines (prepared from aryl nitriles) condense with isoxazolylcyclobutanones (prepared from 3-benzenesulfonyl-3-vinylcyclobutanol) in methanolic KOH to give conformationally restricted 6-isoxazol-5-yl-6,7- dihydro-5H-[1,2]diazocin-4-ones. The solution 1H NMR spectra of dihydrodiazocinone 1a with phenyl moieties at C3 and C8 reveal two conformations of the eight-membered heterocycle that are non-interconverting on the NMR time scale at ambient temperature. The kinetics of the conversion process, followed by 1H NMR between 21 and 70 °C in DMSO solution, yield an activation energy of ∼21 kcal/mol relative to the kinetic conformer and show an equilibrated ratio of ∼5:1 of the thermodynamic to the kinetic conformers. The electronic structure calculations on a model dihydrodiazocinone predict geometries for the two conformations. One of these geometries agrees with the X-ray crystallographic analysis of the thermodynamic conformation of 1a.

Original languageEnglish (US)
Pages (from-to)2480-2485
Number of pages6
JournalJournal of Organic Chemistry
Volume71
Issue number6
DOIs
StatePublished - Mar 17 2006

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Conformations
Nuclear magnetic resonance
Kinetics
Thermodynamics
Nitriles
Geometry
Dimethyl Sulfoxide
Electronic structure
Activation energy
X rays
Temperature
azastene

ASJC Scopus subject areas

  • Organic Chemistry

Cite this

Robins, L. I., Carpenter, R. D., Fettinger, J. C., Haddadin, M. J., Tinti, D. S., & Kurth, M. J. (2006). Diazocinones: Synthesis and conformational analysis. Journal of Organic Chemistry, 71(6), 2480-2485. https://doi.org/10.1021/jo052577a

Diazocinones : Synthesis and conformational analysis. / Robins, Lori I.; Carpenter, Richard D.; Fettinger, James C.; Haddadin, Makhluf J.; Tinti, Dino S.; Kurth, Mark J.

In: Journal of Organic Chemistry, Vol. 71, No. 6, 17.03.2006, p. 2480-2485.

Research output: Contribution to journalArticle

Robins, LI, Carpenter, RD, Fettinger, JC, Haddadin, MJ, Tinti, DS & Kurth, MJ 2006, 'Diazocinones: Synthesis and conformational analysis', Journal of Organic Chemistry, vol. 71, no. 6, pp. 2480-2485. https://doi.org/10.1021/jo052577a
Robins LI, Carpenter RD, Fettinger JC, Haddadin MJ, Tinti DS, Kurth MJ. Diazocinones: Synthesis and conformational analysis. Journal of Organic Chemistry. 2006 Mar 17;71(6):2480-2485. https://doi.org/10.1021/jo052577a
Robins, Lori I. ; Carpenter, Richard D. ; Fettinger, James C. ; Haddadin, Makhluf J. ; Tinti, Dino S. ; Kurth, Mark J. / Diazocinones : Synthesis and conformational analysis. In: Journal of Organic Chemistry. 2006 ; Vol. 71, No. 6. pp. 2480-2485.
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