## Abstract The NMR parameters of (−)‐physostigmine free base (1) in CD~2~Cl~2~, CDCl~3~ and DMSO‐__d__~6~ were used to determine stereospecific assignments. The vicinal homonuclear coupling constants exhibited by the internally diastereotopic pyrrolidinyl protons of the C‐ring can be interpreted a
NMR studies of the conformational behaviour and tautomerism of bis- and tris-saccharidoguanidines
✍ Scribed by Gábor Tóth; Tamás Gáti; István Pintér; József Kovács; Rainer Haessner
- Publisher
- John Wiley and Sons
- Year
- 2001
- Tongue
- English
- Weight
- 139 KB
- Volume
- 39
- Category
- Article
- ISSN
- 0749-1581
- DOI
- 10.1002/mrc.835
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✦ Synopsis
Abstract
The reaction of an acetyl‐protected symmetrical sugar carbodiimide with amines yielded the corresponding trisubstituted guanidine derivatives 2–6 with two or three sugar units. Their tautomerism, isomerism and conformational behaviour were elucidated by application of one‐ and two‐dimensional ^1^H and ^13^C NMR spectroscopy. The rate of tautomerisation was calculated from ROESY exchange measurements. Copyright © 2001 John Wiley & Sons, Ltd.
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