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Application of 1H NMR selective and biselective relaxation times. III—conformational analysis of quinidine in solution

✍ Scribed by Torei Sai; Narao Takao; Makiko Sugiura

Publisher
John Wiley and Sons
Year
1992
Tongue
English
Weight
380 KB
Volume
30
Category
Article
ISSN
0749-1581

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✦ Synopsis

Abstract

A relaxation method was applied to quinidine (1) where cross‐relaxations (σ~ij~) were obtained by ^1^H selective and biselective T~1~ measurements and correlation times for molecular reorientation (τ~c~) were evaluated from the frequency dependence of the non‐selective T~1.~ The interproton distances (r~ij~) were estimated using these σ~ij~ and τ~c~ values, and the conformation of 1 was determined by comparing the estimated r~ij~ values with those calculated from the molecular model. The resulting proposed conformation had the following dihedral angles: ∠ C‐11C‐10C‐3–C‐4 = 150°, ∠ C‐4′C‐9C‐8C‐7 = 50° and ∠ C‐9′C‐4′C‐9C‐8 = 70°. The conformation of the side‐chain (∠ C‐11C‐10C‐3C‐4) is different from the results for the crystal by x‐ray analyses.

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