Study of a δ-hydroxy ketone-hemiketal equilibrium by 2D-NMR exchange spectroscopy for the antibiotic grisorixin: involvement in cationic transport through membranes

doi:10.1016/0300-9084(89)90142-9

Biochimie

Volume 71, Issue 1, January 1989, Pages 125-135

https://doi.org/10.1016/0300-9084(89)90142-9 Get rights and content

Abstract

Study of a δ-hydroxyketone-hemiketal equilibrium in the polyether antibiotic grisorixin was performed with 2D-NMR spectroscopy. The efficiency of ¹³C chemical exchange spectroscopy for the assignment of ¹H and ¹³C resonances, in the 2 forms, was shown, making possible a conformational investigation of both forms.

This equilibrium was observed for grisorixin in solvents of varying polarity, such as CD₂Cl₂, CDCl₃, CD₃CN, or CD₃OD, but not in C₆D₁₂ or C₆D₆. Other related antibiotics with the same terminal heterocycle were described only in the closed hemiacetalic structure.

The low ionic fluxes measured in a bulk chloroformic membrane for grisorixin were explained by this equilibrium, which competed unfavorably with the cation capture process at the water-chloroform interface. This equilibrium would not be present in a phospholipidic bilayer membrane containing the ionophore, published experimental results are taken into account.

The peculiar tautomeric equilibrium observed for grisorixin could be linked to the specific axial stereochemistry of the C7-C8 bond, which creates tension in the globular conformation.

References (29)

J.W. Westley
P. Gachon et al.
J. Antibiotics
(1975)
J. Bolte et al.
Stud. Phys. Theor. Chem.
(1983)
M. Chapel et al.
J. Antibiotics
(1979)
G. Amblard et al.
J. Membr. Biol.
(1985)
J. Jeener et al.
J. Chem. Phys.
(1979)
Y. Huang et al.
J. Am. Chem. Soc.
(1981)
R. Benn
Angew. Chem. Int Ed.
(1982)
J.C. Beloeil et al.
J. Org. Chem.
(1984)
A. Cuer et al.
Nouv. J. Chem.
(1985)

J.E. Whiting et al.

Canad. J. Chem.

(1971)

C.D. Hurd et al.

J. Am. Chem. Soc.

(1952)

T. Fehr et al.

J. Antibiotics

(1977)

T. Fehr et al.

J. Antibiotics

(1979)

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Study of a δ-hydroxy ketone-hemiketal equilibrium by 2D-NMR exchange spectroscopy for the antibiotic grisorixin: involvement in cationic transport through membranes

Abstract

J. Antibiotics

Stud. Phys. Theor. Chem.

J. Antibiotics

J. Membr. Biol.

J. Chem. Phys.

J. Am. Chem. Soc.

Angew. Chem. Int Ed.

J. Org. Chem.

Nouv. J. Chem.

Canad. J. Chem.

J. Am. Chem. Soc.

J. Antibiotics

J. Antibiotics