Metallkomplexe mit biologisch wichtigen Liganden, LXXXIV [1] Halbsandwich-Komplexe von Rhodium(III), Iridium(III), Cobalt(III), Ruthenium(II), Ruthenium(III) und Chrom(III) mit Aminosäureester-Liganden Metal Complexes with Biologically Important Ligands, LXXXIV [1] Half-Sandwich Complexes o f Rhodium(III), Iridium(III), Cobalt(III), Ruthenium(II), Ruthenium(III) and Chromium(III) with Amino Acid Ester Ligands

1996 ◽  
Vol 51 (2) ◽  
pp. 187-200 ◽  
Author(s):  
Ralph Bergs ◽  
Roland Krämer ◽  
Michael Maurus ◽  
Bernhard Schreiner ◽  
Reinhold Urban ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Ester ◽  
Amino Acid Esters ◽  
Ethoxy Group ◽  
Exchange Reactions ◽  
Chelate Complexes ◽  
X Ray ◽  
Ester Exchange ◽  
Half Sandwich ◽  
Acid Esters

Abstract A series of cyclopentadienyl and pentamethylcyclopentadienyl complexes of cobalt, rhodium, iridium, ruthenium and chromium with a-amino-acid esters (L) as ligands was prepared and characterized: Cp*(Cl)2M(L) (1, 2: M = Rh, Ir), Cp(I)2Co(L) (4), [Cp(Ph3P)2Ru(L)]+BF- (6), [Cp(OC)(Ph3P)Ru]+BF- (7) and the paramagnetic compounds Cp*(Cl)2Ru(L) (8) and Cp(Br)2Cr(L) (9). AlaOMe and HisOMe form N ,O and N,N chelate complexes [Cp*(Cl)M(alaOMe)]+BF-4 (3: M = Rh, Ir), [Cp(I)Co(hisOMe)]+BF4. Cp*Co(CO)I2 and GlyOMe gave the N,O-dipeptide ester complex Cp*(I)Co(glyglyOMe)]+BF-4 (5). The crystal structures of Cp(I)2Co(glyOEt) and Cp*(Cl)2Ru(alaOMe) were determined by X-ray diffrac­tion. The complexes 1 and 2 undergo ester exchange reactions with CD3OD. [Cp*MCl2]2 (M = Rh, Ir) catalyze the exchange of the ethoxy group in Me2NCH2CO2Et by CD3OD.

Metal complexes of biologically important ligands, LXXVIII. Synthesis of palladium complexes of ferrocenyl-substituted amino acid derivatives

1995 ◽  
Vol 73 (7) ◽  
pp. 1164-1174 ◽  
Author(s):  
Doris Freiesleben ◽  
Kurt Polborn ◽  
Christian Robl ◽  
Karlheinz Sünkel ◽  
Wolfgang Beck
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Metal Complexes ◽  
Palladium Complexes ◽  
Amino Acid Derivatives ◽  
Amino Acid Esters ◽  
X Ray Diffraction ◽  
Chelate Complexes ◽  
X Ray ◽  
Acid Esters

Schiff bases from ferrocene aldehyde and α-amino acidates react with PdCl2 or Na2PdCl4 to give N,O-chelate complexes (2a–e, 3). The related N-ferrocenylmethylen-α-amino acid esters give, with Pd(OAc)2, cyclopalladated acetate-bridged complexes (4a,b). N,O-chelate complexes (5–7) are obtained from Na2PdCl4 with N-ferrocenylmethyl prolinate and-alaninate as well as with N,N-dibenzyl glycinate. The ethyl ester of N,N-dibenzylglycine and Pd(OAc)2 form the cyclopalladated acetate-bridged complex 8, while the ester of N-monobenzylglycine and Na2PdCl4 affords trans-PdCl2(L)2 with a monodentate N-coordinated ligand. The structures of 2a, 4a, 5, 7, and 9 were determined by X-ray diffraction. Keywords: ferrocene, amino acids, palladium(II) complexes, crystal structures.

Metallkomplexe von biologisch wichtigen Liganden, CVI [1]. Metallkomplexe von Donor-substituierten Oxazolin-5-onen sowie von Bis(oxazolin-5-onen) / Metal Complexes of Biologically Important Ligands CVI [1], Metal Complexes of Donor Substituted Oxazolones and of Bis(oxazolones)

1998 ◽  
Vol 53 (9) ◽  
pp. 965-972 ◽  
Author(s):  
Markus Prem ◽  
Werner Bauer ◽  
Kurt Polbom ◽  
Wolfgang Beck
Keyword(s):  
Amino Acid ◽  
Metal Complexes ◽  
Nucleophilic Addition ◽  
Metal Salts ◽  
Amino Acid Esters ◽  
X Ray Diffraction ◽  
Chelate Complexes ◽  
X Ray ◽  
Close Proximity ◽  
Acid Esters

A series of chelate complexes 1-12 of Cu(II), Ni(II), Pd(II), and Ru(III) with the anion of 2-(2′-hydroxyphenyl)-5(4H)-oxazolone and with 2-(2′-aminophenyl)-5(4H)-oxazolone were prepared from metal salts or from chloro-bridged complexes [(R3P)MCl2]2 (M = Pd, Pt) and [(p-cymene)RuCl2]2. Nucleophilic addition of α-amino acid esters to the bis-chelate complexes M(oxophenyloxazolone)2(M = Ni, Cu) gave the dipeptide derivatives 13-18. Dinuclear Pd(II) and Pt(II) chelate complexes 19-23 were obtained from phenylene- and ethylenebridged bis(oxazolones). The structures of (Et3P)(Cl)Pd(O,N-oxophenyloxazolone) (6) and of Cl2(Et3P)Pt(2,2′-phenylene-bis(4-methyloxazolone)Pt(PEt3)Cl2 (20) were determined by X-ray diffraction. In complex 20 a close proximity of two phenylene H atoms to the metal is observed.

Organometallic Half-Sandwich Complexes Promote the Formation of Linear Oligopeptides from Amino Acid Esters

1996 ◽  
Vol 2 (12) ◽  
pp. 1518-1526 ◽  
Author(s):  
Christian Robl ◽  
Michael Maurus ◽  
Karlheinz Sünkel ◽  
Wolfgang Beck ◽  
Roland Krämer ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Esters ◽  
Sandwich Complexes ◽  
Half Sandwich ◽  
Acid Esters

Metallkomplexe mit biologisch wichtigen Liganden, CXV. Addition von α-Aminosäureestern an [CpFe(CO)3]+: Carbamoylkomplexe Cp(OC)2Fe-C(O)NHCHRCO2R’ und Kristallstruktur von Cp(OC)2Fe-C(O)NHCH2CO2Et / Metal Complexes of Biologically Important Ligands, CXV. Addition of α-Amino Acid Esters to [CpFe(CO)3]+: Carbamoyl Complexes Cp(OC)2Fe-C(O)NHCHRCO2R' and Crystal Structure of Cp(OC)2Fe-C(O)NHCH2CO2Et

1999 ◽  
Vol 54 (3) ◽  
pp. 385-388 ◽  
Author(s):  
Reinhold Urban ◽  
Kurt Polbom ◽  
Wolfgang Beck
Keyword(s):  
Crystal Structure ◽  
Amino Acid ◽  
Metal Complexes ◽  
Amino Acid Esters ◽  
X Ray Diffraction ◽  
Carbonyl Ligand ◽  
X Ray ◽  
Acid Esters

α-Amino acid esters can be added to a carbonyl ligand of [CpFe(CO)3]+CF3SO3- to give the carbamoyl complexes Cp(OC)2Fe-C(O)NHCHRCO2R′ (R = H, Me, CHMe2, CH2Ph; R′ = Et, Me). This type of reaction may be useful for the marking of peptides at the amino end. The crystal structure of Cp(OC)2Fe-C(O)NHCH2CO2Et was determined by X-ray diffraction.

Diphenylphosphino -α -aminosäureester als Liganden in Palladium(II)-und Platin(II)-Komplexen [1] / Diphenylphosphino-α-Amino Acid Esters as Ligands in Palladium(II) and Platinum(II) Complexes [1]

1983 ◽  
Vol 38 (3) ◽  
pp. 365-369 ◽  
Author(s):  
Herbert Trampisch ◽  
Wolfgang Beck
Keyword(s):  
Amino Acid ◽  
Amino Acid Esters ◽  
Chelate Complexes ◽  
Acid Esters

Abstract cis-Dichlorobis(chlorodiphenylphosphine)palladium-and platinum(II) react with N-alkyl-α-amino acid esters to give the complexes MCl2[Ph2PN(R)C(H)(R')CO2Me]2 (M = Pd, Pt; R = CH2Ph, i-C3H7; R' = CH3, CH2Ph). With lysine ester dimeric, bis(chelate) complexes(M = Pd, Pt; R = CH3, C2H5) have been isolated. The reaction of cis-MCl2(PPh2Cl)2 with cysteine and serine methylester affords the complexes MCl2[Ph2P(X)CH2C(H)(NH2)CO2CH3]2 (M = Pd, Pt; X = O, S).

Amino Acid Ester Prodrugs of Acyclovir

1992 ◽  
Vol 3 (3) ◽  
pp. 157-164 ◽  
Author(s):  
L. M. Beauchamp ◽  
G. F. Orr ◽  
P. de Miranda ◽  
T. Bumette ◽  
T. A. Krenitsky
Keyword(s):  
Amino Acid ◽  
Parent Compound ◽  
Parent Drug ◽  
Amino Acid Ester ◽  
Amino Acid Esters ◽  
Simplex Virus ◽  
Ester Prodrug ◽  
Acid Esters

Eighteen amino acid esters of the antiherpetic drug, acyclovir, were synthesized as potential prodrugs for oral administration. The esters were examined for in vitro antiviral activity against herpes simplex virus Type 1 (HSV-1). They were found to have less potency than the parent compound. Their efficiencies as prodrugs were evaluated in rats by measuring the urinary recovery of acyclovir. Ten prodrugs produced greater amounts of the parent drug in the urine. The L-amino acid esters were better prodrugs than the corresponding D- or D, L-isomers, suggesting the involvement of a stereoselective transporter. The L-valyl ester, 256U87, was the best prodrug. Sixty three per cent of its administered dose was excreted as acyclovir in the urine, a considerable improvement over acyclovir itself, for which this value was 19%. Since 256U87 was stable in aqueous solutions, its conversion to acyclovir in vivo was probably enzyme catalyzed. This L-valyl ester prodrug of acyclovir is now undergoing clinical evaluation.

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