Synthesis of N-[2-(2-pyridyl)ethyl]-17a-aza-d-homosteroids and their biomimetic copper-mediated ligand hydroxylations with molecular oxygen
✍ Scribed by Angéla Magyar; Bruno Schönecker; János Wölfling; Gyula Schneider; Wolfgang Günther; Helmar Görls
- Book ID
- 104359889
- Publisher
- Elsevier Science
- Year
- 2003
- Tongue
- English
- Weight
- 258 KB
- Volume
- 14
- Category
- Article
- ISSN
- 0957-4166
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✦ Synopsis
Starting with the oximes of 3-O-methylestrone and 3-O-methyl-13a-estrone we have synthesized 17a-aza steroids as chiral trans-and cis-fused piperidines via a Beckmann rearrangement. These could then be transformed to the corresponding N- [2-(2-pyridyl)ethyl]-17a-aza-steroids. Copper(I) complexes of these bidentate ligands bind and activate molecular oxygen. While the cis-azasteroids are inert towards hydroxylation, in the trans-series hydroxylation occurs b to the N-atom on the ring (C-16) and in the side chain: The former hydroxylation is completely stereoselective with only the (16R)-epimer being produced while the latter oxidation occurs with low stereoselectivity. The influence of how the copper(I) complexes were prepared on the oxidation behavior is discussed.