Analysis of the proton, carbon, and nitrogen NMR spectra of cis,cis- and cis,trans-1,3,5-triaminocyclohexane

✍ Scribed by Chin Yu; Charles L. Dumoulin; George C. Levy

• Publisher: John Wiley and Sons
• Year: 1985
• Tongue: English
• Weight: 588 KB
• Volume: 23
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.1260231114

✦ Synopsis

The proton spectrum of the isomeric mixture of &,cis-and cis,trans-1,3,5-triamino~clohexane was assigned with a 2D COSY experiment. Using Forrest's modified equation and the 2D J spectrum results, the conformations of the two isomers were analysed. The six-membered ring of the cis,trans isomer is flattened by 1,3-diaxial interactions between two amino substituents; in the &,cis isomer, ring pucker is increased owing to non-bonded interaction between the equatorial amino groups and adjacent methylene protons. The -C and "N spin-lattice relaxation of the two isomeric 1,3,5-triaminocyclohexanes was also measured at different pH values; NH, groups rotate faster with decreasing pH. Rotatiodjump rates and barriers are reported, determined from the NzDD ratios between "N and -C nuclei.