Synthetic Studies toward the Partial Ergot Alkaloid LY228729, a Potent 5HT1A Receptor Agonist
摘要:
Synthetic studies on LY228729 (3) afforded two innovative approaches for the construction of this class of partial ergoline 5HT(1a) receptor agonists. The first synthesis is based upon a diastereoselective epoxidation of racemic olefin 5, followed by ring opening and covalent resolution to furnish the key amino alcohol 8. Aziridination of amino alcohol 8, with subsequent tandem hydrogenolysis of the benzylic aziridine and auxiliary bonds, provided access to the optically active primary amine 13. A novel catalytic carboxamidation reaction installed the requisite side chain, Alternatively, the chiral pool was drawn upon for the single stereogenic center by virtue of L-tryptophan, albeit by a more circuitous route than expected. L-Tryptophan was differentially protected and reduced to the indoline diastereomers 26a,b which were separated by fractional crystallization. The two indoline diastereoisomers were independently cyclized by a Friedel-Crafts protocol, which under thermodynamic control afforded enantiomeric ketones 30a. The ketone was deoxygenated with a two-step reduction protocol to intersect the initial route and complete the second total synthesis. The two routes offer complementary access to this exciting class of partial ergot alkaloids.
Tryptophan (Trp) and tryptophan derivatives are C2-arylated. A C–Hactivation process allows the preparation of both protected and unprotected arylated-Trp amino acids, directly from the amino acid precursor and aryl iodides. The obtained compounds are suitable for standard solid-phase peptide synthesis.
Synthesis of nucleotide–amino acid conjugates designed for photo-CIDNP experiments by a phosphotriester approach
作者:Tatyana V Abramova、Olga B Morozova、Vladimir N Silnikov、Alexandra V Yurkovskaya
DOI:10.3762/bjoc.9.326
日期:——
Conjugates of 2'-deoxyguanosine, L-tryptophan and benzophenone designed to study pathways of fast radical reactions by the photo ChemicallyInducedDynamicNuclearPolarization (photo-CIDNP) method were obtained by the phosphotriester block liquid phase synthesis. The phosphotriester approach to the oligonucleotide synthesis was shown to be a versatile and economic strategy for preparing the required
Tyrosine Kinase Inhibitors. 6. Structure−Activity Relationships among <i>N</i>- and 3-Substituted 2,2‘-Diselenobis(1<i>H</i>-indoles) for Inhibition of Protein Tyrosine Kinases and Comparative <i>in Vitro</i> and <i>in Vivo</i> Studies against Selected Sulfur Congeners
作者:H. D. Hollis Showalter、Anthony D. Sercel、Boguslawa M. Leja、Craig D. Wolfangel、Linda A. Ambroso、William L. Elliott、David W. Fry、Alan J. Kraker、Curtis T. Howard、Gina H. Lu、Charles W. Moore、James M. Nelson、Bill J. Roberts、Patrick W. Vincent、William A. Denny、Andrew M. Thompson
DOI:10.1021/jm960689b
日期:1997.2.1
chemistry similar to that developed earlier for the disulfur series, compounds were made from 2-halogeno-3-indolecarboxylic acid precursors bearing various polar functionality at the C-3position and small alkyl substituents at the N-1 position of the indole nucleus. Additional compounds were derived from (R)- or (S)-tryptophan via a novel application of diselenium dichloride as an electrophilic source
Ethyl Thioltrifluoroacetate as an Acetylating Agent with Particular Reference to Peptide Synthesis<sup>1</sup>
作者:Elmer E. Schallenberg、M. Calvin
DOI:10.1021/ja01615a032
日期:1955.5
urn-2632 Unclassfff ed-chemis t y df s t r i b u t i on r UNIVERSITY O CALIFORNIA F Radiation Laboratory Contract No. W-7405-eng-48 ETHYL THIOLTRIFLUOROACETATE A S AN ACETYLATING AGENT WITH PARTICULAR REFERENCE T PEPTIDE SYNTHESIS O Elmer E Schallenberg and M Cal'P-in June, 1954 Berkeley, Calif o m i a
urn-2632 Unclassfff ed-chemis ty df stributi on r UNIVERSITY O CALIFORNIA F Radiation Laboratory Contract No. W-7405-eng-48 ETHYL THIOLTRIFLUOROACETATE AS AN ACETYLATING AGENT WITH PARTICULAR REFERENCE T CALIFORNIA F Radiation Laboratory Contract No. W-7405-eng-48 1954 年 6 月,加利福尼亚州伯克利
Über die Inhaltsstoffe des grünen Knollenblätterpilzes, LIX. Die Raumstruktur der Phallotoxine
Cottoneffekte (Abb. 1) auf. Die Strukturanalyse von 2a durch 1H-NMR (360 MHz) führte zu einem Strukturvorschlag mit M-Helizität. Das N-p-Brombenzolsulfonylderivat 2c mit analogem CD-Spektrum bildete mit Aceton Kristalle, die zur Röntgenstrukturanalyse geeignet waren. Die dadurch erhaltene Raumformel zeigt für das fragliche Strukturelement negative M-Helizität. Demnach enthalten die Phallotoxine den spiegelbildlich