Cycloaddition Reactions of (η6-Tropone)tricarbonylmetal(0) Complexes of Group 6 Metals with Alkynes

2002 ◽  
Vol 67 (11) ◽  
pp. 1635-1646
Author(s):  
Izzet Amour Morkan ◽  
Ayşe Uztetik Morkan
Keyword(s):  
Nmr Spectroscopy ◽  
Ammonium Nitrate ◽  
Crystalline Solids ◽  
Cycloaddition Reactions ◽  
Terminal Alkynes ◽  
Uv Photolysis ◽  
Ir And Nmr Spectroscopy ◽  
Group 6 ◽  
Cerium Iv Ammonium Nitrate ◽  
And Tungsten

(η6-Cyclohepta-2,4,6-trien-1-one)tricarbonylmetal(0) complexes of chromium (2a), molybdenum (2b), and tungsten (2c) are formed when tris(acetonitrile)tricarbonylchromium(0), -molybdenum(0), and -tungsten(0), respectively, are treated photochemically with tropone (cyclohepta-2,4,6-trien-1-one) 1. UV photolysis of 2a-2c and RC≡CR' (R = R' = Ph, Me3Si, Et; R = Ph, R' = Me3Si) in toluene gives the [6+2] cycloadducts, (η4,η2-8,9-diphenylbicyclo[4.2.1]nona-3,5,8-trien-1-one)tricarbonylmetal(0) 3a-3c, (η4,η2-8,9-bis(trimethylsilyl)bicyclo[4.2.1]nona-3,5,8-trien-1-one)tricarbonylmetal(0) 4a-4c, (η4,η2-8,9-diethylbicyclo[4.2.1]nona-3,5,8-trien-1-one)tricarbonylmetal(0) 5a-5c, and (η4,η2-8-phenyl-9-(trimethylsilyl)bicyclo[4.2.1]nona-3,5,8-trien-1-one)tricarbonylmetal(0) 6a-6c. Compounds 2a-2c, 3a-3c, 4a-4c, 5a-5c, and 6a-6c were purified by chromatography, recrystallized and isolated as analytically pure crystalline solids in moderate yields and characterized by mass, IR, and NMR spectroscopy. Pure organic heterobicyclotriene ligands 7a, 8a, 9a, and 10a were isolated from 3a, 4a, 5a, and 6a, respectively, by treatment with cerium(IV) ammonium nitrate (R = R' = Me3Si; R = Ph, R' = Me3Si) or by heating in toluene (R = R' = Ph, Et). It was not possible to isolate the bicyclic complexes resulting from the reactions of 2a-2c with terminal alkynes like phenylacetylene.

Electrochemical Study of Tricarbonyl(η6-cyclooctatetraene)metal(0) Complexes of the Group 6 Elements

1998 ◽  
Vol 53 (8) ◽  
pp. 875-880
Author(s):  
Giirkan Atinç Yilmaz ◽  
Ahmet M. Önal ◽  
Saim Özkar
Keyword(s):  
Cyclic Voltammetry ◽  
Nmr Spectroscopy ◽  
Supporting Electrolyte ◽  
Energy Levels ◽  
Dichloromethane Solution ◽  
Reduction Potentials ◽  
Ir And Nmr Spectroscopy ◽  
Group 6 ◽  
Constant Potential ◽  
Uv Visible

Abstract Tricarbonyl(η6-cyclooctatetraene)metal(0) complexes of the group 6 elements were prepared by using the procedures described in the literature with some minor modifications and identi­fied by IR and NMR spectroscopy. Their electrochemical behavior was studied by using cyclic voltammetry in dichloromethane solution containing 0.1 M tetrabutylammonium tetrafiuorob-orate as supporting electrolyte. Their oxidation and reduction potentials were measured and discussed in terms of the frontier energy levels in connection with the UV-Visible electronic ab­ sorption spectral data. In order to elucidate the mechanism of electrooxidation of the complexes, constant potential electrolysis was performed for one representative example, tricarbonyl(η6-cyclooctatetraene)chromium(O). The IR monitoring of the reaction showed that it is gradually converted to hexacarbonylchromium(O) upon electrolysis at constant potential.

scholarly journals Synthesis of unnatural α-amino esters using ethyl nitroacetate and condensation or cycloaddition reactions

2018 ◽  
Vol 14 ◽  
pp. 2846-2852 ◽  
Author(s):  
Glwadys Gagnot ◽  
Vincent Hervin ◽  
Eloi P Coutant ◽  
Sarah Desmons ◽  
Racha Baatallah ◽  
...  
Keyword(s):  
Ammonium Nitrate ◽  
Cycloaddition Reactions ◽  
Amino Esters ◽  
Ethyl Nitroacetate ◽  
Cerium Iv Ammonium Nitrate

We report here on the use of ethyl nitroacetate as a glycine template to produce α-amino esters. This started with a study of its condensation with various arylacetals to give ethyl 3-aryl-2-nitroacrylates followed by a reduction (NaBH4 and then zinc/HCl) into α-amino esters. The scope of this method was explored as well as an alternative with arylacylals instead. We also focused on various [2 + 3] cycloadditions, one leading to a spiroacetal, which led to the undesired ethyl 5-(benzamidomethyl)isoxazole-3-carboxylate. The addition of ethyl nitroacetate on a 5-methylene-4,5-dihydrooxazole using cerium(IV) ammonium nitrate was also explored and the synthesis of other oxazole-bearing α-amino esters was achieved using gold(I) chemistry.

Reaktionen von C(NMe2)4 mit Carbonylverbindungen der 6. Gruppe. Kristallstrukturen von [C(NMe2)3][(CO)5CrC(O)NMe2], [C(NMe2)3]2[Mo2(CO)10] und [C(NMe2)3][(CO)4Mo(O2CNMe2)] / Reactions of C(NMe2,)4 with Group 6 Carbonyl Compounds. Crystal Structures of [C(NMe2 )3 ][(CO)5 CrC(O)NMe2], [C(NMe2)3]2[Mo2(CO)10] and [C(NMe2)3][(CO)4 Mo(O2CNMe2)]

2001 ◽  
Vol 56 (3) ◽  
pp. 306-314 ◽  
Author(s):  
Wolfgang Petz ◽  
Bernhard Neumüller ◽  
Jörg Lorberth ◽  
Klaus Megges ◽  
Werner Massa
Keyword(s):  
Nmr Spectroscopy ◽  
Crystal Structures ◽  
Carbonyl Compounds ◽  
Ir And Nmr Spectroscopy ◽  
Group 6 ◽  
Independent Molecules

Abstract The reaction of C(NMe2)4 (1) with M(CO)6 (M = Cr, W) in THF solution leads to the anionic carbamoyl complexes [C(NMe2)3][(CO)5MC(O)NMe2] (2a, M = Cr; 2c M = W). In the case of M = Mo the resulting complex 2b is not obtained; instead, the salts [C(NMe2)3]2[Mo2(CO)10] (3) and [C(NMe2)3][(CO)4Mo(O2CNMe2)] (4) are isolated. The crystal structures of 2a, 3, and 4 are presented. In the salt-like compounds no interatomic contacts between anion and cation exist, and the cations are disordered. The structure of 4 shows two independent molecules. The compounds were further characterized by IR and NMR spectroscopy.

Synthesis and Caracterization of some New 1H-3-aryl-7-etoxycarbonyl-6-methyl-pyrazolo[5,1-c][1,2,4]triazoles

2008 ◽  
Vol 59 (1) ◽  
pp. 41-44
Author(s):  
Maria-Daniela Sofei ◽  
Maria Ilici ◽  
Valentin Badea ◽  
Carol Csunderlik ◽  
Vasile-Nicolae Bercean
Keyword(s):  
Mass Spectrometry ◽  
Acetic Acid ◽  
Nmr Spectroscopy ◽  
Sodium Acetate ◽  
Glacial Acetic Acid ◽  
Ir And Nmr Spectroscopy

The synthesis of 1H-3-aryl-7-ethoxycarbonyl-6-methyl-pyrazolo[5,1-c][1,2,4]triazoles (2) was carried out by cyclization of 1H-5-arylidenehydrazino-4-ethoxycarbonyl-3-methyl-pyrazoles (1) in the presence of bromine using glacial acetic acid as solvent and sodium acetate as base. The new nine obtained compounds were characterized by IR and NMR spectroscopy and mass spectrometry.

scholarly journals Oxidative Modification of Native Protein Residues Using Cerium(IV) Ammonium Nitrate

2011 ◽  
Vol 133 (42) ◽  
pp. 16970-16976 ◽  
Author(s):  
Kristen L. Seim ◽  
Allie C. Obermeyer ◽  
Matthew B. Francis
Keyword(s):  
Ammonium Nitrate ◽  
Oxidative Modification ◽  
Native Protein ◽  
Protein Residues ◽  
Cerium Iv Ammonium Nitrate

Photochemistry of Cerium(IV) Ammonium Nitrate (CAN) in Acetonitrile

2021 ◽  
pp. 113440
Author(s):  
Evgeni M. Glebov ◽  
Vjacheslav P. Grivin ◽  
Victor F. Plyusnin ◽  
Roman G. Fedunov ◽  
Ivan P. Pozdnyakov ◽  
...  
Keyword(s):  
Ammonium Nitrate ◽  
Cerium Iv Ammonium Nitrate

Synthesis, Characterization and Complexation Studies with K + and Ca2+ Cations of trans-1.2-Cyclohexanedioxydiacetamides

1988 ◽  
Vol 43 (2) ◽  
pp. 165-170 ◽  
Author(s):  
Whei Oh Lin ◽  
Maria C. B. V. de Souza ◽  
Helmut G. Alt
Keyword(s):  
Nmr Spectroscopy ◽  
Mass Spectroscopy ◽  
H Nmr ◽  
Coordination Sites ◽  
Complexation Studies ◽  
Ir And Nmr Spectroscopy ◽  
Elemental Analyses ◽  
C Nmr

The synthesis of trans-1.2-cyclohexanedioxydiacetamides starting with trans-1.2-cyclohexane-diol is described. Eleven of these compounds are characterized by IR, 1H NMR, 13C NMR and mass spectroscopy as well as elemental analyses. Most of these compounds are suitable ionophors for the cations K+ and Ca2+. The coordination sites of these ligands in the 1:2 complexes were determined by IR and NMR spectroscopy

Solid-state regioselective nitration of activated hydroxyaromatics and hydroxycoumarins with cerium (IV) ammonium nitrate

2005 ◽  
Vol 2005 (11) ◽  
pp. 733-735 ◽  
Author(s):  
Nemai C. Ganguly ◽  
Sanjoy Dutta ◽  
Mrityunjoy Datta ◽  
Prithwiraj De
Keyword(s):  
Solid State ◽  
Ammonium Nitrate ◽  
High Efficiency ◽  
Solvent Free ◽  
High Melting ◽  
Microwave Assisted ◽  
Solvent Free Conditions ◽  
High Yields ◽  
Regioselective Nitration ◽  
Cerium Iv Ammonium Nitrate

Predominant ortho-selective mononitration of low-melting and liquid phenols and hydroxycoumarins in moderate to high yields has been accomplished upon grinding with solid cerium (IV) ammonium nitrate (CAN). Microwave-assisted expeditious CAN-mediated nitration of relatively high melting phenols and hydroxycoumarins with high efficiency and selectively under solvent-free conditions has been also developed to address the problems of sluggishness and low yield for these reluctant substrates.

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