Synthesis of N-[2-(2-pyridyl)ethyl]-17a-aza-d-homosteroids and their biomimetic copper-mediated ligand hydroxylations with molecular oxygen

Magyar, Angéla; Schönecker, Bruno; Wölfling, János; Schneider, Gyula; Günther, Wolfgang; Görls, Helmar

doi:10.1016/s0957-4166(03)00362-8

Cited by 9 publications

(2 citation statements)

References 28 publications

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“…[7] Very recently, however, two examples of b-hydroxylation of nonactivated CÀH bonds using method A have been described. [8,9] We were able to show that 17-IMPY-3-methoxy-estra-1,3,5(10)-triene (1, Scheme 1) can be stereo-and regioselectively hydroxylated in the 12b-position (g-hydroxylation) in nearly 50 % yield using method B. [7] To investigate the stereochemical implications of this interesting reaction employing IMPY ligands, we describe herein two new 17-IMPY steroidal ligands 3 and 6 (Scheme 2) and the IMPY derivative of (R)-camphor 12 (Scheme 3).…”

Section: Resultsmentioning

confidence: 99%

“…It seems to be much more difficult to hydroxylate nonactivated CÀH bonds. The work of Thompson (N,N,N',N'-tetraethyl ethylenediamine [5] ) and Reglier and co-workers {N,N-bis[2-(2-pyridyl)ethyl]aminopropane [6] and -cyclopentane [6] }, our own work {17b-N-[2-(2-pyridyl)ethyl]amino-, 17b-(2-pyridylmethyl)amino steroids, [7] and a 17 a-aza-N-[2-(2-pyridyl)ethyl]amino steroid [8] }, and work by Masuda et al [cis,cis-1,3,5-tris(isobutylamino)-cyclohexane [9] ] is summarized in Figure 1. Using conformationally more restricted bidentate ligands incorporating an iminomethyl-or iminoethyl-2-pyridine moiety at the 17-position of a steroid molecule, we have observed for the first time a regio-and stereospecific ghydroxylation of a nonactivated CH 2 group.…”

Section: Introductionmentioning

confidence: 90%

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Intramolecular γ‐Hydroxylations of Nonactivated CH Bonds with Copper Complexes and Molecular Oxygen

Schönecker

Zheldakova

Lange

et al. 2004

Chemistry A European J

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Copper(I) complexes incorporating the isomeric bidentate ligands IMPY (iminomethyl-2-pyridines) or AMPY (aminomethylene-2-pyridines) are quite unusual in their ability to bind and activate molecular oxygen. Using these complexes, hydroxylations of nonactivated CH, CH2, or CH3 groups in the gamma-position in relation to the imino-nitrogen atom, and with a specific orientation of one H atom with respect to the binuclear Cu-O species, can be achieved in synthetically useful yields. Through mechanistic studies employing conformationally well-defined molecules (for example, cyclic isoprenoids), coupled with solid-state X-ray structure analyses and force-field calculations, we postulate a seven-membered transition state for this reaction in which six atoms lie approximately in a plane. This plane is defined by the positions of the lone pairs on the nitrogen atoms, as well as the copper and the oxygen atoms. For a successful hydroxylation, one hydrogen atom should be located close to this plane. Prediction of the stereochemical course of these reactions is possible based on a simple geometrical criterion. The convenient introduction of IMPY and AMPY groups as auxiliaries into oxo and primary amino compounds and the simple hydrolysis after the hydroxylation procedure has allowed the synthesis of 3-hydroxy-1-oxo and 3-hydroxy-1-amino compounds. If desired, the 3-hydroxy-1-IMPY and -1-AMPY compounds can be reduced with NaBH4 to obtain 3-hydroxy-1-aminomethylpyridines. For a successful hydroxylation procedure, the method employed for the synthesis of the CuI complexes is very important. Starting either from CuI salts or from CuII salts with a subsequent reduction with benzoin/triethylamine may turn out to be the better way, depending on the ligand and the molecular structure.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 90%

Intramolecular γ‐Hydroxylations of Nonactivated CH Bonds with Copper Complexes and Molecular Oxygen

Schönecker

Zheldakova

Lange

et al. 2004

Chemistry A European J

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Rearrangements of Hydroxylamines, Oximes and Hydroxamic Acids

Pereira

Santos²

2010

Patai's Chemistry of Functional Groups

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Introduction The [3,3]‐Sigmatropic Rearrangements The [2,3]‐Sigmatropic Rearrangements The Dyotropic Rearrangements The B amberger Rearrangements The B eckmann Rearrangements The N eber Rearrangements The L ossen Rearrangement Other Rearrangements

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A new dioxime ligand and its trinuclear copper(II) complex: Synthesis, characterization and optical properties

Karipçin

Dede

Çağlar

et al. 2007

Optics Communications

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Synthesis of N-[2-(2-pyridyl)ethyl]-17a-aza-d-homosteroids and their biomimetic copper-mediated ligand hydroxylations with molecular oxygen

Cited by 9 publications

References 28 publications

Intramolecular γ‐Hydroxylations of Nonactivated CH Bonds with Copper Complexes and Molecular Oxygen

Intramolecular γ‐Hydroxylations of Nonactivated CH Bonds with Copper Complexes and Molecular Oxygen

Rearrangements of Hydroxylamines, Oximes and Hydroxamic Acids

A new dioxime ligand and its trinuclear copper(II) complex: Synthesis, characterization and optical properties

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