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Licl-Mediated Direct Insertion of Magnesium Into Aryl, Heteroaryl and Benzylic Halides

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Dissertation zur Erlangung des Doktorgrades der Fakultät für Chemie und Pharmazie der Ludwig-Maximilians-Universität München LiCl-Mediated Direct Insertion of Magnesium Into Aryl, Heteroaryl and Benzylic Halides. Regio- and Chemoselective Synthesis of 5-Membered Ring Heterocycles. Fabian Michel Piller aus Paris, Frankreich München 2010 Erklärung Diese Dissertation wurde im Sinne von § 13 Abs. 3 der Promotionsordnung vom 29. Januar 1998 von Prof. Dr. Paul Knochel betreut. Ehrenwörtliche Versicherung Diese Dissertation wurde selbstständig, ohne unerlaubte Hilfe erarbeitet. München, am 1. März 2010 ………………………………………… Fabian Michel Piller Dissertation eingereicht am: 1. März 2010 1. Gutachter: Prof. Dr. Paul Knochel 2. Gutachter: Prof. Dr. Konstantin Karaghiosoff Mündliche Prüfung am: 7. April 2010 This work was carried out from December 2006 to February 2010 under the guidance of Prof. Dr. Paul Knochel at the Fakultät für Chemie und Pharmazie of the Ludwig-Maximilians-Universität, Munich. I would like to thank Prof. Dr. Paul Knochel for giving me the opportunity to prepare my Ph.D. thesis in his group, for the chance of working on the most elegant reaction in organic chemistry and for his invaluable support and guidance throughout this time. I am also very grateful to Prof. Dr. K. Karaghiosoff for agreeing to act as a referee, as well as to Prof. Dr. K. Wanner, Prof. Dr. H. Zipse, Prof. Dr. H. R. Pfaendler and Prof. Dr. A. Kornath for the interest shown in this manuscript and their agreement to take part in the examination. I thank Tobias Blümke, Marcel Kienle, Albrecht Metzger, Christoph Rohbogner, Andreas Wagner and Stefan Wunderlich for the careful correction of this manuscript. I thank many of the past and present members of the Knochel group for creating a wonderful ambience inside and outside of the lab. I am very grateful to Sebastian Bernhardt, Thomas Kunz, Dr. Christian Rauhut, Dr. Armin Stoll and Silvia Zimdars for being the best lab mates one could possibly wish for. Additionally, I want to thank Tobias Blümke, Dr. Andrei Gavryushin, Benjamin Haag, Albrecht Metzger and Matthias Schade for the fruitful collaboration in the field of insertion chemistry. I also thank Dr. Felix Kopp for the many nights spent with music and wine in NYC, Augsburg and Munich. My stomach would like to thank all the people that helped me avoid the gourmet food in the Mensa throughout the years. A special thank-you to all the members of the best band that ever rocked Großhadern. It was a privilege to play with you! I would also like to thank Vladimir Malakhov, Simon Matthe, Renate Schröder and Yulia Tsvik for their help in organizing everyday life in the lab and in the office, as well as the analytical team of the LMU for their invaluable help. A very special thanks goes out to my family and friends, especially to my parents and to Anja for their endless love and support throughout the time of my Ph.D. I couldn’t have done this without you! Parts of this Ph.D. Thesis have been published 1) F. M. Piller, P. Appukkuttan, A. Gavryushin, M. Helm, P. Knochel, Convenient Preparation of Polyfunctional Arylmagnesium Reagents Using a Direct Magnesium Insertion in the Presence of LiCl, Angew. Chem. Int. Ed. 2008, 47, 6802-6806; Angew. Chem. 2008, 120, 6907-6911. 2) A. Metzger, F. M. Piller, P. Knochel, Polyfunctional Benzylic Zinc Chlorides by the Direct Insertion of Magnesium in the Presence of LiCl and ZnCl2, Chem. Commun. 2008, 5824-5826. 3) P. Knochel, P. Appukkuttan, A. Gavryushin, G. Manolikakes, A. Metzger, M. Mosrin, F. M. Piller, C. J. Rohbogner, M. A. Schade, S. H. Wunderlich, Functionalization of Heterocyclic Compounds using Polyfunctional Magnesium and Zinc Reagents, Pfizer In-House Journal Synthon, 2008. 4) F. M. Piller, P. Knochel, Regio- and Chemoselective Synthesis of Fully Substituted Thiophenes, Org. Lett. 2009, 11, 445-448. 5) F. M. Piller, A. Metzger, M. A. Schade, B. A. Haag, A. Gavryushin, P. Knochel, Preparation of Polyfunctional Arylmagnesium, Arylzinc and Benzylic Zinc Reagents Using Magnesium in the Presence of LiCl, Chem. Eur. J. 2009, 15, 7192-7202. 6) T. D. Blümke, F. M. Piller, P. Knochel, Preparation of Highly Functionalized Alkylzinc Halides from Alkyl Bromides using Mg, ZnCl2 and LiCl, Chem. Commun. 2010, DOI: 10.1039/c001845g. 7) F. M. Piller, T. Bresser, M. K. R. Fischer, P. Knochel, Preparation of Functionalized Cyclic Enol Phosphates by Halogen-Magnesium Exchange and Directed Deprotonation Reactions, manuscript in preparation. 8) F. M. Piller, P. Knochel, Functionalization of Furan, Thiophene, Pyrrole and Indole Derivatives via Ortho-Magnesiation Reactions, manuscript in preparation. A. INTRODUCTION ............................................................................................................ 1 1. Overview ....................................................................................................................................................... 2 2. Preparation of Magnesium Reagents ......................................................................................................... 4 2.1. Magnesium Insertion Into Carbon-Halogen Bonds .............................................................................. 4 2.2. The Halogen-Magnesium Exchange Reaction ..................................................................................... 5 2.3. Directed Deprotonation Using Magnesium Amide Bases.................................................................... 8 3. Preparation of Zinc Reagents ................................................................................................................... 10 4. Objectives ................................................................................................................................................... 12 B. RESULTS AND DISCUSSION ..................................................................................... 15 1. LiCl-Mediated Direct Insertion of Magnesium Into Aryl, Heteroaryl and Benzylic Halides ............. 16 1.1. Magnesium Insertion in the Presence of LiCl Into Aryl and Heteroaryl Bromides ........................... 16 1.2. Preparation of Aryl- and Heteroarylzinc Reagents by Magnesium Insertion in the Presence of LiCl and ZnCl2 ........................................................................................................................................... 22 1.3. Regioselectivity of Zinc and Magnesium Insertions into Polybrominated Arenes ............................ 24 1.4. Preparation of Benzylic Zinc Reagents by the Insertion of Magnesium in the Presence of LiCl and ZnCl2 .................................................................................................................................................. 28 1.5. Preparation of Alkylzinc Reagents by the Insertion of Magnesium in the Presence of LiCl and ZnCl2 33 1.6. Larger Scale Preparations of Organomagnesium and Organozinc Reagents ..................................... 35 2. Regio- and Chemoselective Synthesis of Functionalized 5-Membered-Ring Heterocycles ................. 40 2.1. Preparation of Polyfunctional Furan, Thiophene, Indole and Pyrrole Derivatives ............................ 40 2.2. Regio- and Chemoselective Synthesis of Fully Substituted Thiophenes ........................................... 47 3. Preparation of Functionalized Enol Phosphates by Halogen-Magnesium Exchange and Directed Deprotonation Reactions .................................................................................................................................... 56 4. 1-Aryliminozinc Reagents as Acyl Anion Equivalents ........................................................................... 60 5. Summary and Outlook .............................................................................................................................. 62 5.1. LiCl-Mediated Magnesium Insertions Into Organic Halides ............................................................. 62 5.2. Regio- and Chemoselective Synthesis of Functionalized 5-Membered-Ring Heterocycles .............. 64 5.3. Preparation of Functionalized Enol Phosphates by Halogen-Magnesium Exchange and Directed Deprotonation Reactions .................................................................................................................... 66 5.4. 1-Aryliminozinc Reagents as Acyl Anion Equivalents ...................................................................... 67 C. EXPERIMENTAL SECTION ...................................................................................... 69 1. General Considerations ............................................................................................................................. 70 2. LiCl-Mediated Magnesium Insertions into Organic Halides ................................................................. 73 2.1. Magnesium Insertion in the Presence of LiCl into Aryl and Heteroaryl Bromides ........................... 73 2.1.1. Typical Procedure for the Magnesium Insertion in the Presence of LiCl (TP1) ........................... 73 2.1.2. Typical Procedure for Cross-Coupling Reactions (TP2) ............................................................... 73 2.1.3. Typical Procedure for Acylations and Allylations (TP3) .............................................................. 73 2.1.4. Preparation of Title Compounds ................................................................................................... 74 2.2. Preparation of Aryl- and Heteroarylzinc Reagents by Magnesium Insertion in the Presence of
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  • UNITED STATES PATENT OFFICE 2,677,686 PYRAZINEDERVATIVES and METHO) of PREPARING the SAME Victor K

    UNITED STATES PATENT OFFICE 2,677,686 PYRAZINEDERVATIVES and METHO) of PREPARING the SAME Victor K

    Patented May 4, 1954 2,677,686 UNITED STATES PATENT OFFICE 2,677,686 PYRAZINEDERVATIVES AND METHO) OF PREPARING THE SAME Victor K. Smith, Jr., Feari River, and Samuel Kushner, Nanuet, N. Y., assignors to American Cyanamid Company, New York, N. Y., a corpo ration of Maine No Drawing. Application 5uly 22, 1952, Serial No. 300,336 8 Claims. (C. 260-250) 2 This invention relates to mono-substituted ous layer is extracted with a solvent, such as di pyrazine. More particularly, it relates to substi ethyl ether. The ether can be concentrated and tuted-2-carbonyl pyrazine. the desired compound crystallized out Or the The role of vitamins in nutrition is well known ether can be removed and the product distilled. i and assumes greater importance as new informa 5, The reaction of the present invention may be tion is made available concerning the particular carried out at a temperature of -10° to 15° C. function of each. Recently it has been found The reaction is complete in from about a few that folic acid was effective in curing macrocytic ininutes up to about tWO hours. anemias and other blood conditions. Also, Com The process of the present invention is de pounds which are folic acid antagonistS, Such as scribed in greater particularity by the following aninopterin, have been found useful in treating specific examples which are given by way of ill abnormal blood conditions such as leukemia. lustration and not limitation. it is well established that nicotinamide is an im Eacample 1 portant, vitamin of the B complex group and its deficiency is the specific cause of pelagira.