𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Structural studies of benzophenanthridine alkaloid free bases by NMR spectroscopy

✍ Scribed by Pavlína Sečkářová; Radek Marek; Jiří Dostál; Roger Dommisse; Eddy L. Esmans

Publisher
John Wiley and Sons
Year
2001
Tongue
English
Weight
195 KB
Volume
40
Category
Article
ISSN
0749-1581

No coin nor oath required. For personal study only.

✦ Synopsis

The free bases of eight quaternary benzo[c]phenanthridine alkaloids (chelerythrine, sanguilutine, chelirubine, chelilutine, sanguirubine, sanguinarine, nitidine and fagaronine) were investigated by 1 H and 13 C NMR spectroscopy. The pseudobases (the 6-hydroxy-5,6-dihydro derivatives) were found to be the only products of the alkalization of these alkaloids using sodium carbonate in DMSO-d 6 solution. This observation differs from the measurements of preparative free bases in CDCl 3 solution, where the structures of the bimolecular aminoacetals were unequivocally confirmed. According to the results obtained, in biological systems, in the presence of excess of water and ions, free bases of the investigated alkaloids are assumed to adopt the pseudobase (6-hydroxy derivative) structure. In contrast, in less polar media (C 6 D 6 , CDCl 3 ), the formation of the bimolecular aminoacetal structure is preferred.

📜 SIMILAR VOLUMES

Stereochemical study of anagyrine-type q
Stereochemical study of anagyrine-type quinolizidine alkaloids by 15N and 2D NMR spectroscopy
✍ Zimin Liu; Li Yang; Zhongjian Jia; Jihong Chen 📂 Article 📅 1992 🏛 John Wiley and Sons 🌐 English ⚖ 224 KB

## Abstract The configurations of anagyrine, thermopsine and two other anagyrine‐type quinolizidine alkaloids were revised using ^15^N and 2D NMR in a 400 MHz NMR study. Their ^1^H and ^13^C NMR chemical shifts are given in detail.

ChemInform Abstract: Structural Study of
ChemInform Abstract: Structural Study of Some Fluoroborate Glasses by NMR and IR Spectroscopy.
✍ E. V. GRISHCHUK; N. P. EFRYUSHINA; V. P. DOTSENKO; E. R. GUBANOVA 📂 Article 📅 2010 🏛 John Wiley and Sons ⚖ 28 KB 👁 2 views

Structural Study of Some Fluoroborate Glasses by NMR and IR Spectroscopy. -The dependence of the structure of some glasses in the systems CaO- CaF 2 -B 2 O 3 andY 2 O 3 -MF 2 -B 2 O 3 (M: Mg, Ca, Sr) on their compositions is studied by NMR and IR-methods. The introduction of metal fluorides in B 2

Structural and conformational study of m
Structural and conformational study of macrocyclic polyethers by NMR spectroscopy and molecular modeling
✍ A. Philippon; M. Laguerre; M. Petraud; I. Pianet 📂 Article 📅 1997 🏛 John Wiley and Sons 🌐 English ⚖ 287 KB 👁 2 views

Two macrocyclic polyether isomers were obtained by radical cyclization of (E)-8-iodo-3,6-dioxaoctyl-3ethoxycarbonylpropenoate and separated by liquid-solid chromatography over silica gel. They were characterized, for the Ðrst time, by two-dimensional NMR ; notably, the HMBC experiment gave access to