Model complexes of products expected from N-terminal hydrolysis of polypeptides containing trifunctional amino acids. Tetraminecobalt(III) complexes of glutamic and aspartic acids

Legg, J. Ivan; Steele, Jack

doi:10.1021/ic50104a017

Cited by 20 publications

(13 citation statements)

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“…The chiral aspartato complexes were synthesized essentially as before from [(en) 2 Co(CO 3 )]Cl and (S)-aspartic acid with a charcoal catalyst in aqueous suspension, 60 but the earlier separation and isolation procedures were improved. Thus, the Λand ∆-[(en) 2 Co(S-Asp(O Ϫ )O)] ϩ cations were efficiently separated using trisodium citrate eluent on AG 50W-X2 resin and each diastereoisomer (acid form) was isolated as its dichloride salt in order to avoid the potentially hazardous perchlorate salts used earlier.…”

Section: Synthesesmentioning

confidence: 99%

“…Thus, the Λand ∆-[(en) 2 Co(S-Asp(O Ϫ )O)] ϩ cations were efficiently separated using trisodium citrate eluent on AG 50W-X2 resin and each diastereoisomer (acid form) was isolated as its dichloride salt in order to avoid the potentially hazardous perchlorate salts used earlier. 60 However, the perchlorate salt Λ(ϩ) 578 -[(en) 2 Co(S-Asp-(OH)O)](ClO 4 ) 2 was also isolated for characterization purposes and its absolute stereochemistry was established by X-ray crystallographic analysis. The isolated chloride salts, Λand ∆-[(en) 2 Co(S-Asp(OH)O)]Cl 2 , were diastereoisomerically pure but also contained some ethanol and water of crystallisation and, occasionally, slight amounts of the derivative monoethyl ester complexes.…”

Section: Synthesesmentioning

confidence: 99%

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Novel metal complex synthons for chiral 4-azaleucine, 2,3-diaminopropanoic acid and its elaboration

Barfod¹,

Bendahl²,

Hammershøi³

et al. 1999

J. Chem. Soc., Dalton Trans.

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Efficient syntheses of chiral Co() complexes with 2,3-diaminopropanoic acid (A 2 pr) have been developed. In these complexes, the amino acid zwitterion [A 2 pr(H ϩ )O Ϫ ] is bound didentate through the carboxylate and N 2 -amine groups while the N 3 -ammonio group [pK a = 7.19(2)] is unprotected. Syntheses of Λ(ϩ) 578 -and ∆(Ϫ) 578 -[(en) 2 Co-(S-A 2 pr(H ϩ )O)]Cl 3 ؒH 2 O were effected stereoretentively from the similarly didentate aspartato complexes Λand ∆-[(en) 2 Co(S-Asp(OH)O)]Cl 2 in reaction sequences transforming the unbound β-carboxyl group into an amine by Curtius rearrangement. The absolute configuration of the Λ(ϩ) 578 -[(en) 2 Co(S-Asp(OH)O)](ClO 4 ) 2 complex was determined by X-ray crystallographic analysis and defined the absolute stereochemistry of diastereoisomers and derived products. Methylation of the N 3 -amine group of Λ(ϩ) 578 -[(en) 2 Co(S-A 2 pr(H ϩ )O)]Cl 3 ؒH 2 O gave the (S)-4azaleucine complex Λ(ϩ) 578 -[(en) 2 Co(S-A 2 pr(Me 2 H ϩ )O)](C 4 F 9 SO 3 ) 3 from which enantiopure (ϩ)-(S)-2-amino-3-(dimethylamino)propanoic acid dihydrochloride hemihydrate [=(ϩ)-(S)-A 2 pr(Me 2 )ؒ2HClؒ0.5H 2 O] was obtained upon reductive removal of the protecting Co(III) centre. Racemic 4-azaleucine was easily produced by an alternative, but also metal-dependent method and the intermediate rac-(p)-[(tren)Co(A 2 pr(Me 2 H ϩ )O)]Zn 2 Cl 7 ؒ3H 2 O obtained in a simple solid-phase synthesis by selective reduction of achiral (p)-[(tren)Co(2-amino-3-(dimethylamino)acrylyl chloride)] 3ϩ ion adsorbed on AG 50W-X2 cation exchange resin. The epimerization rate of the Λ-[(en) 2 Co(S-A 2 prO)] 2ϩ complex ion was first-order in [HO Ϫ ] [k E = 3.8 × 10 Ϫ2 dm 3 mol Ϫ1 s Ϫ1 , I = 1.00 M (NaClO 4 ), 25 ЊC] with the diastereoisomer ratio K C (=[Λ-R]/[Λ-S]) = 0.77(2) at equilibrium in 10 mM NaOH. However, no epimerization was observed after at least 3 hours in 6 M HCl at 45 ЊC.

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Section: Synthesesmentioning

confidence: 99%

Section: Synthesesmentioning

confidence: 99%

Novel metal complex synthons for chiral 4-azaleucine, 2,3-diaminopropanoic acid and its elaboration

Barfod¹,

Bendahl²,

Hammershøi³

et al. 1999

J. Chem. Soc., Dalton Trans.

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“…was found between the rate of growth in control medium and in those to which 3H20 had been added. Preparation of[Iglutamyl-2-3H]glutathione (Carbonato)bis(ethylenediamine) cobalt (III) chloride, prepared by the method of Springb0rg & Schaffer (1973), was complexed with glutathione (Legg & Steele, 1971). Treatment of an aliquot of the preparation with NaBH4 released free glutathione with a recovery of 88%.…”

Section: Purity Ofglutathionementioning

confidence: 99%

The role of glutathione in amino-acid absorption. Lack of correlation between glutathione turnover and amino-acid absorption by the yeast Candida utilis

Robins¹,

Davies²

1981

Biochemical Journal

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The rate of degradation of glutathione has been determined in the yeast Candida utilis by using a method that minimizes the effect of amino-acid recycling. When yeast are grown in amino-acid-free medium, the half-life of glutathione was found to be 230 min. C. utilis was also found to absorb various L-amino acids rapidly without producing any significant decrease in the half-life of glutathione. While the gamma-glutamyl cycle is thus operating in C. utilis, the rate of degradation of glutathione is found to be 100 times too slow for the cycle to be mediating the transport of these amino acids.

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“…The reaction scheme suggested by Adamson and Gonick1 for the oxidation of ethylenediaminetetraacetatocobaltate-(II) by ferricy anide ion has been substantiated by Huchital and Wilkins2 and by work in this group. 3 The reaction involves an inner-sphere electron-transfer equilibrium step to a successor complex followed by the breakup of this complex to the final products. The driving force for the decomposition of this complex is the ring closure of the EDTA moiety.…”

Section: Introductionmentioning

confidence: 99%

Interaction of multidentate cobalt(II)-chelate complexes with ferricyanide ion. II. CoIIDTPA (diethylenetriaminepentaacetic acid)

Huchital¹,

Hodges²

1973

Inorg. Chem.

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Model complexes of products expected from N-terminal hydrolysis of polypeptides containing trifunctional amino acids. Tetraminecobalt(III) complexes of glutamic and aspartic acids

Cited by 20 publications

References 0 publications

Novel metal complex synthons for chiral 4-azaleucine, 2,3-diaminopropanoic acid and its elaboration

Novel metal complex synthons for chiral 4-azaleucine, 2,3-diaminopropanoic acid and its elaboration

The role of glutathione in amino-acid absorption. Lack of correlation between glutathione turnover and amino-acid absorption by the yeast Candida utilis

Interaction of multidentate cobalt(II)-chelate complexes with ferricyanide ion. II. CoIIDTPA (diethylenetriaminepentaacetic acid)

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