caa a22 4500 467919135 CHVBK 20180406152911.0 cr unu---uuuuu 170328e20060101xx s 000 0 eng 10.1007/s00706-005-0406-8 doi (NATIONALLICENCE)springer-10.1007/s00706-005-0406-8 Azasteroids. Reaction of Chiral N , N -Maleoyl Amino Acids with 1-(1-Trimethylsiloxyvinyl)-3,4-dihydronaphthalene [Elektronische Daten] [Anja Bodtke, Milton T. Stubbs, Hans-Hartwig Otto] Summary.: The cycloaddition between N,N-maleoyl amino acid esters and 1-(1-trimethylsiloxyvinyl)-3,4-dihydronaphthalene gave 11-(trimethylsiloxy) derivatives of 16-azaestra-1,3,5(10)-trienes. These were transformed by desilylation into the parent 11-oxo-derivatives, which reacted with hydroxylamines to 11-hydroxyimino derivatives. The stereochemistry of the products was elucidated using different NMR methods, HPLC, CD, X-ray structure analysis, and calculations. It was found that mixtures of diastereoisomers were obtained from these cycloadditions. Reactions using chiral maleoyl amino acid derivatves did not change this result. The chiral center did not provoke stereoselectivity, probably caused by the flexibility of the chiral side chain. A directing influence of the side chain was found only in reactions with derivatives of phenylalanine. This might be explained as an interaction between the aromatic system and the carbonyl groups of the imide moiety. This interaction kept the aromatic ring in its position in the final product, and was found in the X-ray crystallographic analysis, and agreed with results of calculations. Springer-Verlag/Wien, 2006 Keywords. Azasteroids nationallicence 2-Trialkylsiloxy-1,3-diene nationallicence Maleimides, chiral nationallicence Diels-Alder reaction nationallicence Crystallographic structure analysis nationallicence Bodtke Anja Department of Pharmaceutical/Medicinal Chemistry (PMC), Institute of Pharmacy, Ernst-Moritz-Arndt-University, 17487, Greifswald, Germany aut Stubbs Milton T. Institute of Physical Biotechnology, University of Halle, 06099, Halle, Germany aut Otto Hans-Hartwig Department of Pharmaceutical/Medicinal Chemistry (PMC), Institute of Pharmacy, Ernst-Moritz-Arndt-University, 17487, Greifswald, Germany aut Monatshefte für Chemie / Chemical Monthly Springer-Verlag 137/1(2006-01-01), 83-103 0026-9247 137:1<83 2006 137 706 https://doi.org/10.1007/s00706-005-0406-8 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00706-005-0406-8 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Bodtke Anja Department of Pharmaceutical/Medicinal Chemistry (PMC), Institute of Pharmacy, Ernst-Moritz-Arndt-University, 17487, Greifswald, Germany aut NATIONALLICENCE 700 1- Stubbs Milton T. Institute of Physical Biotechnology, University of Halle, 06099, Halle, Germany aut NATIONALLICENCE 700 1- Otto Hans-Hartwig Department of Pharmaceutical/Medicinal Chemistry (PMC), Institute of Pharmacy, Ernst-Moritz-Arndt-University, 17487, Greifswald, Germany aut NATIONALLICENCE 773 0- Monatshefte für Chemie / Chemical Monthly Springer-Verlag 137/1(2006-01-01), 83-103 0026-9247 137:1<83 2006 137 706 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer