Wiechert, Rudolf

Kerb Ulrich, Sauer Gerhard, Wiechert Rudolf, Henderson David, Nishino Yukishige, Beier Sybille US Patent No. 4,591,585 May 27, 1986 Assigned to Schering Aktiengesellschaft (Berlin and Bergkamen, DE)... 

Stereochemistry-Congresses. 2. Organic compounds-Synthesis-Congresses. I. Wiechert, Rudolf, 1928-. Ottow, E. (Eckhard), 1953-. III. Schollkopf, K. (Klaus), 1953-. IV. Schulz, B.-G. (Bemd-Gunter), 1950-. 

Roaderich Siissmuth Rudolf-Wiechert-Professor fiir Biologische Chemie, Technische Universitaat Berlin, Institut Fiir Chemie/FG Organische Chemie, Strasse des 17. Juni 124, D-10623 Berlin, Germany (e-mail suessmuth chem.tu-berlin.de)... 

Around 1970, chemists at Schering (Ulrich Eder, Gerhard Sauer, Rudolf Wiechert) and concurrently at Hoffmann-La Roche (Zoltan Hajos, David Parrish) had found an improved Michael addition of 2-ethylcyclopentane-l,3-di-one [61] to methyl vinyl ketone. If water is used in place of methanol, and catalytic amounts of potassium hydroxide are present, then the yield is increased from 54 to 81%. [62, 63] The higher homologues can be synthesised in an analogous manner as well. [64] Robinson annulation, in presence of 30 mole% proline, leads in good yield to a bicydic hydroxy-ketone. After dehydration, crystallisation and reduction with sodium borohydride, the enantiomerically pure bicydic ketone is obtained, which is required for Coreys synthesis. 

It is noteworthy that Rudolf Wiechert (Fig. 6.18) at Scheringhad already synthesised drospirenone back in the 1970s. [72] However, it took around 25 years before the pharmacological potential of this compound was fiiUy recognised and the drug received market approval. From a chemical viewpoint, drospirenone is an attractive molecule. Unusual structural characteristics are the two cyclopropane rings and the spirolactone moiety. In contrast to the previous... 

Stereoselektive synthesis lectures honouring Prof. Dr. Dr. h.c. Rudolf Wiechert/E. Ottow, K. Schbllkopf, B.-G. Schulz (Hrsg.). p.cm. Papers from a one-day symposium in honor of Wiechert s 65th birthday. Includes bibliographical references and index. 

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