𝔖 Bobbio Scriptorium
✦   LIBER   ✦

NMR and theoretical conformational studies of the anticholinergic physostigmine

✍ Scribed by Norma F. Santos-Sánchez; Martha S. Morales-Ríos; Pedro Joseph-Nathan

Publisher
John Wiley and Sons
Year
2001
Tongue
English
Weight
139 KB
Volume
39
Category
Article
ISSN
0749-1581

No coin nor oath required. For personal study only.

✦ Synopsis

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 as arising from an interconverting profile of conformations at the fast exchange limit. Physostigmine undergoes epimerization in solution via inversion of the labile chirotopic and stereogenic N1 nitrogen atom, which results in the formation of (N − R,S)‐N1Me diastereoisomers. Protonation at the N1 nitrogen leads to the (N − S)‐N1 Me diastereoisomer of the corresponding salt of 1. Four conformational archetypes were calculated by molecular mechanics based on X‐ray crystallographically determined physostigmine. Copyright © 2001 John Wiley & Sons, Ltd.

📜 SIMILAR VOLUMES

Experimental and theoretical NMR and IR
Experimental and theoretical NMR and IR studies of the side-chain orientation effects on the backbone conformation of dehydrophenylalanine residue
✍ Aneta M. Buczek; Tomasz Ptak; Teobald Kupka; Małgorzata A. Broda 📂 Article 📅 2011 🏛 John Wiley and Sons 🌐 English ⚖ 285 KB

## Abstract Conformation of __N__‐acetyl‐(__E__)‐dehydrophenylalanine __N__′, __N__′‐dimethylamide (Ac‐(__E__)‐ΔPhe‐NMe~2~) in solution, a member of (__E__)‐α, β‐dehydroamino acids, was studied by NMR and infrared spectroscopy and the results were compared with those obtained for (__Z__) isomer. To

NMR studies of the conformational behavi
NMR studies of the conformational behaviour and tautomerism of bis- and tris-saccharidoguanidines
✍ Gábor Tóth; Tamás Gáti; István Pintér; József Kovács; Rainer Haessner 📂 Article 📅 2001 🏛 John Wiley and Sons 🌐 English ⚖ 139 KB

## 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 t

Conformational studies of monoterpenes.
Conformational studies of monoterpenes. II–conformational studies of bicyclo[3.1.1]heptane derivatives by 13C NMR
✍ Collette M. Holden; David Whittaker 📂 Article 📅 1975 🏛 John Wiley and Sons 🌐 English ⚖ 316 KB

## Abstract The carbon‐13 spectra of seventeen bicyclo[3.1.1]‐heptane derivatives have been recorded and assigned. Study of the C‐6 and C‐7 chemical shifts permits the conformations to be assigned to the bridged chair, Y‐shaped, or bridged boat conformations. The spectrum of verbenone is anomalous

A 1H NMR and theoretical investigation o
A 1H NMR and theoretical investigation of the conformations of some monosubstituted cyclobutanes
✍ Raymond J. Abraham; Paul Leonard; Cláudio F. Tormena 📂 Article 📅 2010 🏛 John Wiley and Sons 🌐 English ⚖ 195 KB

## Abstract The complete analysis of the complex ^1^H NMR spectra of some monosubstituted cyclobutanes was achieved to give all the ^1^H chemical shifts and ^__n__^__J__~HH~ (__n__ = 2, 3 and 4) coupling constants in these molecules. The substituent chemical shifts of the substituents in the cyclob