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Schwarz M, Vollmann M, Wartchow R, Butenschön H. Synthesis and cyclic voltammetry of some new metal carbene substituted cyclopentadienyliron half sandwich complexes. J Organomet Chem 2005. [DOI: 10.1016/j.jorganchem.2005.02.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Wartchow R, Roeper JS, Hoffmann ΗMR. Crystal structures of ethanol hemisolvates of (1S,3R,4S,8S,9R)-1N-boranyl-6' - methoxy-cinchonan-9-ol, C20H27BN2O2 · ½C2H5OH, and (1S,3S,4S,8S,9R)-1N-boranyl- 10,11 -didehydro-6' -methoxy-cinchonan-9-ol, C20H25BN2O2 · ½C2H5OH. Z KRIST-NEW CRYST ST 2005. [DOI: 10.1524/ncrs.2005.220.14.89] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Hotje U, Wartchow R, Binnewies M. Chemischer Transport fester L�sungen. 15 [1]. Der Chemische Transport von Mischphasen in Systemen TiS2/TiSe2, TiS2/TaS2, TiSe2/TaSe2 und TaS2/TaSe2. Z Anorg Allg Chem 2005. [DOI: 10.1002/zaac.200400398] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Strotmann M, Wartchow R, Butenschön H. High yield synthesis and structures of some achiral and chiral (diphosphine)tetracarbonylchromium(0) chelate complexes with tetracarbonyl(norbornadiene)chromium(0) as complexation reagent. ARKIVOC 2004. [DOI: 10.3998/ark.5550190.0005.d07] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Franz MH, Röper S, Wartchow R, Hoffmann HMR. The first and second cinchona rearrangement. Two fundamental transformations of alkaloid chemistry. J Org Chem 2004; 69:2983-91. [PMID: 15104435 DOI: 10.1021/jo030363s] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Stereochemistry, products, and driving forces of the "first and second Cinchona rearrangement" have been investigated and a unified theory is presented. The first cage expansion affords [3.2.2]azabicyclic alpha-amino ether and is formulated via a configurationally stable bridgehead iminium ion and quasiequatorial nucleophilic attack. The second cage expansion affords beta-functionalized [3.2.2]azabicycles. In this case a nonclassical nitrogen-bridged cation is postulated to account for retention of configuration and potential reversibility of the cage expansion. The second rearrangement is favored for the so-called cinch bases (6'-R = H) in trifluoroethanol. Stereoelectronic factors, electron demand at C9, ground state conformation, and solvent type are crucial in all cases. A two-step protocol for preparing 9-epi-configured Cinchona alkaloids from 9-nat precursors is described.
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Albrecht U, Wartchow R, Hoffmann HMR. Stereocontrolled Construction of 6 · 5 · 6 and 5 · 5 · 6 Ring Systems by Radical Tandem Cyclization. ACTA ACUST UNITED AC 2003. [DOI: 10.1002/anie.199209101] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Wartchow R, Müller L, Binnewies M. Crystal structure of manganese gallium germanium silicon oxide (garnet type), Mn3(Ga2-ζ,Mn,)(Ge3-zSiz)O12 (y = 0.6, ζ = 0.14; j=0.44, z=0), and of manganese gallium germanium silicon oxide (braunite type), Mn(Mn6-yGay)(Si1-zGez)O12 (y = 0.7, z = 0.4). Z KRIST-NEW CRYST ST 2003. [DOI: 10.1524/ncrs.2003.218.jg.405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Wartchow R, Müller L, Binnewies M. Crystal structure of manganese gallium germanium silicon oxide (garnet type), Mn3(Ga2–yMny)(Ge3–zSiz)O12 (y = 0.6, z = 0.14; y = 0.44, z = 0), and of manganese gallium germanium silicon oxide (braunite type), Mn(Mn6–yGay)(Si1–zGez)O12 (y = 0.7, z = 0.4). Z KRIST-NEW CRYST ST 2003. [DOI: 10.1524/ncrs.2003.218.4.373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Abstract Ga1.4Ge2.86Mn3.6O12Si0.14 (1), cubic, Ia3̅d (No. 230), a = 12.043(3) Å, V = 1746.6 Å3, Z = 8, Rgt(F) = 0.028, wRref(F2) = 0.062, T = 300 K. Ga1.56Ge3Mn3.44O12 (2), cubic, Ia3̅d (No. 230), a = 12.049(3) Å, V = 1749.3 Å3, Z = 8, Rgt(F) = 0.023, wRref(F2) = 0.052, T = 300 K. Ga0.7Ge0.4Mn6.3O12Si0.6 (3), tetragonal, I41/acd (No. 142), a = 9.464(4) Å, c = 18.78(3) Å, V = 1682.1 Å3, Z = 8, Rgt(F) = 0.023, wRref(F2) = 0.053, T = 300 K.
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Yong L, Hofer E, Wartchow R, Butenschön H. Oxidative Addition of Hydrosilanes, Hydrogermane, and Hydrostannane to Cyclopentadienylcobalt(I) Bearing a Pendant Phosphane Ligand: Cyclopentadienylhydridocobalt(III) Chelate Complexes with Silyl, Germyl, and Stannyl Ligands. Organometallics 2003. [DOI: 10.1021/om030581b] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Schnebel M, Weidner I, Wartchow R, Butenschön H. Reactions between Benzocyclobutenone Tricarbonylchromium Complexes and Lithium Dialkylphosphides: A New Route to Isochromanones. European J Org Chem 2003. [DOI: 10.1002/ejoc.200300390] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Schütte M, Wartchow R, Binnewies M. Shape Controlling Synthesis— Formation of Fe3Si by the Reaction of Iron with Silicon Tetrachloride and Crystal Structure Refinement. Z Anorg Allg Chem 2003. [DOI: 10.1002/zaac.200300125] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Knappwost-Gieseke C, Nerenz F, Wartchow R, Winterfeldt E. High-pressure selectivity studies--a simple route to a homochiral wistarin precursor. Chemistry 2003; 9:3849-58. [PMID: 12916109 DOI: 10.1002/chem.200204524] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The cycloaddition of spirobutenolide 3 to the homochiral cyclopentadiene 1 at 6.5 kbar leads exclusively to cycloadduct 5. Subsequent Diels-Alder or Michael additions again favour the cyclohexenone double bond; this perfect chemo- regio- and face selectivity was employed for a short and efficient approach to the wistarin framework.
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Röper S, Franz MH, Wartchow R, Hoffmann HMR. Fused triazoles via tandem reactions of activated Cinchona alkaloids with azide ion. Second Cinchona rearrangement exemplified. Org Lett 2003; 5:2773-6. [PMID: 12889871 DOI: 10.1021/ol034719y] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] Intramolecular 1,3-dipolar cycloadditions of cinchona azides to the C10-C11 alkyne and C10-C11 olefin unit of the alkaloid have been designed via tandem strategy. A variety of fused triazoles and triazolines with a bis-azahomotwistane skeleton have been prepared. In trifluoroethanol, O-mesylcinchonidine 7-OMs and NaN(3) furnish triazole 8 as well as cage-expanded 1,5-diazatricyclo[4.4.1.0(3,8)]undecane derivative 10. Both fused triazoles 8 and 10 are formed with retention of configuration at C9 and C3, respectively. 1-Azabicyclo[3.2.2]cage expansion is shown to be reversible.
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Röper S, Franz MH, Wartchow R, Hoffmann HMR. Preparation of enantiopure 1-azabicyclo[3.2.2]nonanes functionalized at carbon C3, from cinchonine and cinchonidine. stereoselective solvolysis and an easily enolizable ketone. J Org Chem 2003; 68:4944-6. [PMID: 12790606 DOI: 10.1021/jo026890d] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Solvolysis of C9 mesylated cinchonidine 1-OMs and cinchonine 2-OMs in solvent MeOH, EtOH, and CF(3)CH(2)OH affords ring-expanded 1-azabicyclo[3.2.2]nonanes oxygenated at carbon C3 ("second Cinchona rearrangement"). The newly introduced substituents at C3 and the neighboring quinolyl group Q' at C2 adopt quasiequatorial positions. The derived 1-azabicyclo[3.2.2]nonan-3-ones 5 and 6 are easily equilibrated. On contact with MeOD uptake of deuterium takes place at room temperature.
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Kirschning A, Kunst E, Ries M, Rose L, Schönberger A, Wartchow R. Polymer-bound haloate(I) anions by iodine(III)-mediated oxidation of polymer-bound iodide: Synthetic utility in natural product transformations. ARKIVOC 2003. [DOI: 10.3998/ark.5550190.0004.617] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Röper S, Wartchow R, Hoffmann HMR. S(N)1-like reactions of bicyclic alpha-amino ethers with sulfur, nitrogen, and carbon nucleophiles. Synthesis of 1-azabicyclo[3.2.2]nonanes functionalized at carbon C2 and C6 with complete stereocontrol. Org Lett 2002; 4:3179-82. [PMID: 12227743 DOI: 10.1021/ol026342m] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] In the presence of nucleophiles, Lewis acid mediated cleavage of alpha-amino ethers derived from quincorine and quincoridine affords a variety of C2-substituted and C6-vinylated 1-azabicyclo[3.2.2]nonanes. These are enantiopure and are formed in S(N)1-like reactions with complete stereocontrol. There is no leakage into 2-Nu en route to product 1-Nu or vice versa. Me(3)SiCN provides new Strecker-type alpha-amino nitriles. In the presence of TTMPP-BF(3).OEt(2), the ketene acetal Me(2)C=C(OMe)OSiMe(3) delivers enantiopure bicyclic beta-amino acid esters.
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Leinweber D, Schnebel M, Wartchow R, Wey H, Butenschön H. Ninhydrin as a Source of Naphthoquinone Acetals and Benzocycloheptenetrione Derivatives, and the Trapping of an Oxacarbene Derived from a Cyclopentanone. European J Org Chem 2002. [DOI: 10.1002/1099-0690(200207)2002:14<2385::aid-ejoc2385>3.0.co;2-s] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Proemmel S, Wartchow R, Hoffmann H. Synthesis and studies of marine natural products: the dictyoxetane core from 8-oxabicyclo[3.2.1]oct-6-en-3-ones. Tetrahedron 2002. [DOI: 10.1016/s0040-4020(02)00622-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Dongol K, Wartchow R, Butenschön H. Tricarbonyl(3-methoxybenzocyclobutenedione)chromium: Regioselective Nucleophilic Addition Reactions, Dianionic Oxy-Cope Rearrangements, Regioselective Intramolecular Aldol Additions, and a Rare Case of an Anionic 1-Vinylcyclobutenol−Cyclohexadienol Rearrangement. European J Org Chem 2002. [DOI: 10.1002/1099-0690(200206)2002:12<1972::aid-ejoc1972>3.0.co;2-h] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Hoffmann HMR, Eggert U, Walenta A, Weineck E, Schomburg D, Wartchow R, Allen FH. Trispiro[2.1.2.1.2.1]dodecane-4,8,12-trione and other oligomers of carbonylcyclopropane. The organozinc route. J Org Chem 2002. [DOI: 10.1021/jo00287a022] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Kieć-Kononowicz K, Drabczyńska A, Pękala E, Michalak B, Müller CE, Schumacher B, Karolak-Wojciechowska J, Duddeck H, Rockitt S, Wartchow R. New developments in A1 and A2 adenosine receptor antagonists. PURE APPL CHEM 2001. [DOI: 10.1351/pac200173091411] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The aim of this article is to briefly present progress in the development of the potent adenosine receptor (AR) antagonists with high selectivity for either A1, A2A, or A2B ARs. The structural requirements for each AR subtype were discussed as well as their potential therapeutic use. In the search for new AR antagonists, series of imidazo-, pyrimido-, and diazepino-purindione derivatives as well as oxazolo-, oxazino-, and oxazepino-purindiones were designed, synthesized, and preliminarily evaluated in pharmacological studies. Oxygen-containing tricyclic derivatives were shown to be moderately potent AR antagonists exhibiting selectivity either for A1 or A2A ARs. Tricyclic purindiones with nitrogen in the third ring were generally more A2A AR selective. The compounds tested in vivo according to the Antiepileptic Drug Development Program of the National Institutes of Health (USA) were generally active as anticonvulsants in chemically induced seizures.
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Voigt B, Wartchow R, Butenschön H. Lithiated Heterocycles as Substrates for Dianionic Oxy-Cope Rearrangements − Chelation Accounts for Regioselective Enolate Hydrolysis. European J Org Chem 2001. [DOI: 10.1002/1099-0690(200107)2001:13<2519::aid-ejoc2519>3.0.co;2-b] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Trân-Huu-Dâu ME, Wartchow R, Winterfeldt E, Wong YS. New cyclohexadienone derivatives: preparation and chiral discrimination in high-pressure Diels-Alder cycloadditions. Chemistry 2001; 7:2349-69. [PMID: 11446638 DOI: 10.1002/1521-3765(20010601)7:11<2349::aid-chem23490>3.0.co;2-c] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A wide range of cyclohexadienones has been synthesised in order to study their reactivity and their regio- and stereoselectivity with the enantiopure diene 1 under high-pressure conditions. Computational investigations were used to point out some parameters which affect the reactivity in this high chiral discrimination process. In addition, the resulting [4+2] cycloadducts allowed the preparation of new polyfunctional cyclohexenone derivatives.
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Pfeifer A, Wartchow R, Binnewies M. Crystal structure of diindium digermanate, In2(Ge2O7). Z KRIST-NEW CRYST ST 2001. [DOI: 10.1524/ncrs.2001.216.14.201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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