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Updated: Aug 9, 2026

Structure and Coordination Determination of Peptide-metal Complexes Using 1D and 2D 1H NMR
Published on: December 16, 2013
Conformational study of eight-membered diazocine turn mimics by two-dimensional NMR spectroscopy
J W Bean1, J Briand, J L Burgess
1Department of Physical & Structural Chemistry, SmithKline Beecham Pharmaceuticals, King of Prussia, PA 19406-0939.
Abstract:
The eight-membered ring conformations of two diazocine turn mimics, methyl-[2,5-dioxo-3-(S)-(3-omega-tosyl-guanidino-propyl)-4-methyl-octahy dro- 1,4-diazocin-1-yl]acetate (I) and methyl-[2,5-dioxo-3-(S)-(3-omega-tosyl-guanidino-propyl)-octahydro-1,4- diazocin-1-yl]acetate (II), were determined using torsion angle constraints derived from 3J(C,H) coupling constants extracted from 13C-filtered TOCSY spectra with 13C in natural abundance. For I, the torsion angle constraints derived from 3J(C,H) coupling constants were in agreement with torsion angle constraints derived from 3J(H,H) coupling constants extracted from a P.E. COSY spectrum. Similar 3J(C,H) coupling constants were found for I and II, and they shared an identical eight-membered ring conformation characterized by two cis-amide bonds and a staggered conformation of the trimethylene group in which the H3 proton is proximal to both the H6 and H8 protons.
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