Optical resolution of asymmetric amines by preferential crystallization as lasalocid salts

Westley, John; Evans, R. H.; Blount, John F.

doi:10.1021/ja00460a036

Cited by 50 publications

(21 citation statements)

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“…The absolute configurations of these amines are known (9). Oxidation of the Sisomer with hydrogen peroxide and sodium tungstate (10) afforded the oxime in about 60% yield with little or no racemization as determined by nmr spectrometry in the presence of an optical shift reagent.…”

Section: Resultsmentioning

confidence: 99%

Syntheses of optically active 2-tetrahydrofuran derivatives

Bélanger¹,

Williams²

1983

Can. J. Chem.

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Section: Resultsmentioning

confidence: 99%

Syntheses of optically active 2-tetrahydrofuran derivatives

Bélanger¹,

Williams²

1983

Can. J. Chem.

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“…X-ray studies have demonstrated that lasalocid forms 1:1 monomeric complexes with 1-amino-1-phenylethane (2) for crystals grown from nonpolar solvents (22). This is in contrast to the dimeric structures (Na2X2, BaX2) observed in the crystalline state with the less bulky alkali and alkaline earth ions (4,15).…”

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confidence: 99%

“…We followed the procedure of Westley et al (22) to generate the lasalocid complexes of dopamine (3b) and R(+)-norepinephrine (3c).…”

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“…Westley and coworkers have demonstrated that lasalocid A forms crystalline complexes with primary biogenic amines (22) and this has led us to undertake structural and kinetic investigations of these complexes in solution. These amines include 2-aminoheptane (1), the phenethylamines [1-amino-l-phenylethane (2), and 1-amino-2-phenylethane (3a)], and the catecholamines [dopamine (3b) and norepinephrine (3c)] (Fig.…”

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“…2) The amine-lasalocid complexes of 1, 2, and 3a were generated by mixing equimolar ratios of the amine and lasalocid in methylene chloride solution, followed by gradual addition of n-hexane to precipitate the complexes. We followed the procedure of Westley et al (22) to generate the lasalocid complexes of dopamine (3b) and R(+)-norepinephrine (3c).…”

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Biogenic amine-ionophore interactions: Structure and dynamics of lasalocid (X537A) complexes with phenethylamines and catecholamines in nonpolar solution

Shen¹,

Patel²

1977

Proc. Natl. Acad. Sci. U.S.A.

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The ionophore lasalocid A forms 1:1 complexes with phenethylamines (1-amino-1-phenylethane and 1-amino-2-phenylethane) and catecholamines (dopamine and norepinephrine) in nonpolar solution. We have undertaken high-resolution proton nuclear magnetic resonance studies to deduce structural and kinetic information on the ionophore-biogenic amine complexes in chloroform solution. The coupling constant, chemical shift, and relaxation time data demonstrate that the lasalocid backbone conformation and the primary amine binding sites in the complexes are similar to those determined earlier for the alkali and alkaline earth complexes of this ionophore in solution. The exchange of lasalocid between the free acid (HX) and the primary amine complexes (RNH3X) in chloroform solution have been evaluated from the temperaturedependent line shapes at superconducting fields. The kinetic parameters associated with the unimolecular dissociation (RNH3X T RNH2 + HX) and the bimolecular exchange k2 (RNH3X + HX* RNH3X* + HX) reactions have been deduced from an analysis of the lifetime of the complex as a function of the reactant concentrations. The relative stability of the complex decreases in the order phenyl > n-pentyl for substituents on the carbon a to the amino group (1-amino-l-phenylethane and 2-aminoheptane) and phenyl > 3,4-dihydroxyphenyl for substituents on the carbon # to the amino group (l-amino-2-phenylethane and dopamine). These results suggest that nonpolar interactions between the biogenic amine side chain and the lasalocid molecule contribute to the stability of the complex in solution. Lasalocid A [see Fig. 1, for chemical sequence (1) and revised numbering system (2)] belongs to the family of linear carboxylic polyether antibiotics that transport alkali ions across membranes (5, 6). The backbone of these ionophores adopts a folded head-to-tail conformation stabilized by intramolecular hydrogen bonds between the carboxylic and hydroxyl groups (refs. 5 and 6 and the references therein). The ionophores complex the alkali ions through their hydroxyl, ether, carbonyl, and carboxylate groups, resulting in a hydrophobic exterior which facilitates the transport of metal ions across membranes. The conformation of lasalocid resembles a flat disc with a polar and a nonpolar face (7-10), and it differs from the other carboxylic polyether antibiotics of larger dimensions which can form polar cavities for metal ion coordination. This permits the polar face of lasalocid to coordinate ions with different radii and charges, including alkali, alkaline earth (3,4,(11)(12)(13)(14), rare earth (15), and transition (16) metal ions as well as amines (17). The alkali and alkaline earth ions are sandwiched between the polar faces of two lasalocid anions in nonpolar solution (3, 12, 13) and in crystals grown from the same medium (7-10). By contrast, monomeric structures, in which the metal ion chelates to the polar face of one lasalocid anion and solvent, are observed in polar media (4,14).A number of biological studies have implica...

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Geometry of the ether, sulphide and hydroxyl groups and structural chemistry of macrocyclic and non‐cyclic polyether compounds

Goldberg

1989

PATAI'S Chemistry of Functional Groups

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Optical resolution of asymmetric amines by preferential crystallization as lasalocid salts

Cited by 50 publications

References 4 publications

Syntheses of optically active 2-tetrahydrofuran derivatives

Syntheses of optically active 2-tetrahydrofuran derivatives

Biogenic amine-ionophore interactions: Structure and dynamics of lasalocid (X537A) complexes with phenethylamines and catecholamines in nonpolar solution

Geometry of the ether, sulphide and hydroxyl groups and structural chemistry of macrocyclic and non‐cyclic polyether compounds

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