Highly functionalized alkenes produced from base-free organocatalytic Wittig reactions: (E)-3-benzylidenepyrrolidine-2,5-dione, (E)-3-benzylidene-1-methylpyrrolidine-2,5-dione and (E)-3-benzylidene-1-tert-butylpyrrolidine-2,5-dione

2016 ◽  
Vol 72 (6) ◽  
pp. 504-508 ◽  
Author(s):  
Marie-Luis Schirmer ◽  
Anke Spannenberg ◽  
Thomas Werner
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Carbonyl Compounds ◽  
Wittig Reaction ◽  
Phosphonium Salts ◽  
Asymmetric Unit ◽  
Free Base ◽  
Fundamental Transformation ◽  
Wittig Reactions ◽  
Centrosymmetric Dimers

The Wittig reaction is a fundamental transformation for the preparation of alkenes from carbonyl compounds and phosphonium ylides. The ylides are prepared prior to the olefination step from the respective phosphonium salts by deprotonation utilizing strong bases. A first free-base catalytic Wittig reaction for the preparation of highly functionalized alkenes was based on tributylphosphane as the catalyst. Subsequently we developed a system employing a phospholene oxide as a pre-catalyst and trimethoxysilane as reducing agent which operates under milder conditions. The title compounds, (E)-3-benzylidenepyrrolidine-2,5-dione, C11H9NO2, (I), the methylpyrrolidine derivative, C12H11NO2, (II), and thetert-butylpyrrolidine derivative, C15H17NO2, (III), have been synthesized by base-free catalytic Wittig reactions. In the crystal of (I), molecules are linked into centrosymmetric dimersviapairs of N—H...O hydrogen bonds. Furthermore, in the crystal structure of (III), there are two molecules in the asymmetric unit, whereas in (I) and (II), only one molecule is present.

scholarly journals 1-(4-Methoxyphenylsulfonyl)-5-methyl-5-phenylimidazolidine-2,4-dione

2009 ◽  
Vol 65 (6) ◽  
pp. o1207-o1208 ◽  
Author(s):  
Abid Hussain ◽  
Shahid Hameed ◽  
Helen Stoeckli-Evans
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Benzene Ring ◽  
Title Compound ◽  
Phenyl Group ◽  
Monoclinic Space Group ◽  
Asymmetric Unit ◽  
Space Group ◽  
Compound C ◽  
Centrosymmetric Dimers

The title compound, C17H16N2O5S, crystallized in the chiral monoclinic space groupP21, with two enantiomeric molecules (AandB) in the asymmetric unit. It is composed of a methylimidazolidine-2,4-dione unit substituted with a phenyl group and a 4-methoxyphenylsulfonyl group. The benzene ring mean planes are inclined to one another by 22.20 (14)° in moleculeAand by 15.82 (13)° in moleculeB. In the crystal structure, theAandBmolecules are linked by N—H...O hydrogen bonds, forming centrosymmetric dimers. A number of C—H...O interactions are also present in the crystal structure, leading to the formation of a three-dimensinoal network.

scholarly journals Powder study of 3-azabicyclo[3.3.1]nonane-2,4-dione form 2

2006 ◽  
Vol 62 (7) ◽  
pp. o3046-o3048 ◽  
Author(s):  
Ashley T Hulme ◽  
Philippe Fernandes ◽  
Alastair Florence ◽  
Andrea Johnston ◽  
Kenneth Shankland
Keyword(s):  
Crystal Structure ◽  
Simulated Annealing ◽  
Hydrogen Bonds ◽  
Powder Diffraction ◽  
Title Compound ◽  
Variable Temperature ◽  
Polycrystalline Sample ◽  
Asymmetric Unit ◽  
X Ray ◽  
Compound C

A polycrystalline sample of a new polymorph of the title compound, C8H11NO2, was produced during a variable-temperature X-ray powder diffraction study. The crystal structure was solved at 1.67 Å resolution by simulated annealing from laboratory powder data collected at 250 K. Subsequent Rietveld refinement yielded an R wp of 0.070 to 1.54 Å resolution. The structure contains two molecules in the asymmetric unit, which form a C 2 2(8) chain motif via N—H...O hydrogen bonds.

The effect of partial methylation of the glycine amino group on crystal structure inN,N-dimethylglycine and its hemihydrate

2012 ◽  
Vol 68 (8) ◽  
pp. o283-o287 ◽  
Author(s):  
Vasily S. Minkov ◽  
Elena V. Boldyreva
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Water Molecules ◽  
Amino Group ◽  
Asymmetric Unit ◽  
Partial Methylation ◽  
Space Groups ◽  
Carboxylate Groups ◽  
Anhydrous Compound ◽  
Additional Hydrogen

N,N-Dimethylglycine, C4H9NO2, and its hemihydrate, C4H9NO2·0.5H2O, are discussed in order to follow the effect of the methylation of the glycine amino group (and thus its ability to form several hydrogen bonds) on crystal structure, in particular on the possibility of the formation of hydrogen-bonded `head-to-tail' chains, which are typical for the crystal structures of amino acids and essential for considering amino acid crystals as mimics of peptide chains. Both compounds crystallize in centrosymmetric space groups (PbcaandC2/c, respectively) and have twoN,N-dimethylglycine zwitterions in the asymmetric unit. In the anhydrous compound, there are no head-to-tail chains but the zwitterions formR44(20) ring motifs, which are not bonded to each other by any hydrogen bonds. In contrast, in the crystal structure ofN,N-dimethylglycinium hemihydrate, the zwitterions are linked to each other by N—H...O hydrogen bonds into infiniteC22(10) head-to-tail chains, while the water molecules outside the chains provide additional hydrogen bonds to the carboxylate groups.

scholarly journals 2,6-Bis(4-methoxybenzylidene)cyclohexanone

2006 ◽  
Vol 62 (5) ◽  
pp. o1910-o1912 ◽  
Author(s):  
Ray J. Butcher ◽  
H. S. Yathirajan ◽  
B. K. Sarojini ◽  
B. Narayana ◽  
J. Indira
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Photon Absorption ◽  
Intermolecular Hydrogen Bonds ◽  
Two Photon Absorption ◽  
Two Photon ◽  
Compound C ◽  
Centrosymmetric Dimers

The title compound, C22H22O3, demonstrates a two-photon absorption. Its metrical parameters are similar to those of related cyclohexanone derivatives. In the crystal structure, two sets of centrosymmetric dimers formed by weak C—H...O intermolecular hydrogen bonds combine to form molecular tapes along [101].

SYNTHESIS OF ISOTOPICALLY LABELLED OLEFINS VIA THE WITTIG REACTION

1965 ◽  
Vol 43 (5) ◽  
pp. 1614-1624 ◽  
Author(s):  
J. G. Atkinson ◽  
M. H. Fisher ◽  
D. Horley ◽  
A. T. Morse ◽  
R. S. Stuart ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Dimethyl Sulfoxide ◽  
Wittig Reaction ◽  
Low Molecular Weight ◽  
Phosphonium Salts ◽  
Reaction Conditions ◽  
Selective Labelling ◽  
Wittig Reactions

A new application of the Wittig reaction to the preparation of olefins of low molecular weight which allows selective labelling in the vinyl or allyl positions with isotopes of hydrogen and carbon has been developed. Using the modification of the Wittig reaction introduced by E. J. Corey, in which a solution of the methylsulfinyl carbanion in dimethyl sulfoxide serves as the base, a series of olefins from C2 to C8 were synthesized. The synthesis was applied to the preparation of the following labelled compounds: 5-methylene-14C-bicyclo[2.2.1]hept-2-ene; propene-1-14C; 1-butene-1-14C; propene-1-d1; 2-methylpropene-1,1-d2; 2-methyl-d3-propene-3,3,3-d3; 2-methyl-2-butene-4,4,4-d3; 2-methyl-d3-2-butene-1,1,1-d3; methylene-d2-cyclohexane. For the synthesis of carbon-labelled olefins the reaction has few limitations since the intermediates and products are isotopically stable under the reaction conditions. Deuterium-labelled olefins can be obtained from deuterated formaldehyde or β-deuterated phosphonium salts, but α-deuteroketones and aldehydes and α-deuterophosphonium salts lose the isotope to the solvent.In all the Wittig reactions, benzene was formed as a by-product in 10–15% yield. The mechanism of benzene formation is probably analogous to that proposed by Seyferth involving the decomposition of a pentacovalent phosphorous intermediate.

scholarly journals Dopaminium nitrate

2014 ◽  
Vol 70 (5) ◽  
pp. o571-o572
Author(s):  
Sofian Gatfaoui ◽  
Houda Marouani ◽  
Thierry Roisnel ◽  
Hassouna Dhaouadi
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Three Dimensional ◽  
Supramolecular Network ◽  
Asymmetric Unit ◽  
Nitrate Ions ◽  
Nitrate Anions

The asymmetric unit of the title salt [systematic name: 2-(3,4-dihydroxyphenyl)ethanaminium nitrate], C8H12NO2+·NO3−, contains two independent cations and two independent nitrate anions. The crystal structure consists of discrete nitrate ions stacked in layers parallel to (010). These layers are linkedviathe dopaminium cations by O—H...O, N—H...O and weak C—H...O hydrogen bonds, forming a three-dimensional supramolecular network.

scholarly journals Crystal structure ofN,N′-bis[2-((benzyl){[5-(dimethylamino)naphthalen-1-yl]sulfonyl}amino)ethyl]naphthalene-1,8:4,5-tetracarboximide 1,2-dichlorobenzene trisolvate

2016 ◽  
Vol 72 (10) ◽  
pp. 1503-1508
Author(s):  
Miguel Ángel Claudio-Catalán ◽  
Felipe Medrano ◽  
Hugo Tlahuext ◽  
Carolina Godoy-Alcántar
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Dihedral Angles ◽  
Inversion Symmetry ◽  
Asymmetric Unit ◽  
Naphthalene Ring ◽  
Π Interactions ◽  
Compound C ◽  
Ring Centroid ◽  
Supramolecular Chains

The asymmetric unit of the title compound, C56H50N6O8S2·3C6H4Cl2, contains two half-molecules of the parent,AandB, which both have crystallographic inversion symmetry, together with three 2,3-dichlorobenzene molecules of solvation. MoleculesAandBare conformationally similar, with dihedral angles between the central naphthalenediimide ring and the peripheral naphthalene and benzyl rings of 2.43 (7), 81.87 (7)° (A) and 3.95 (7), 84.88 (7)° (B), respectively. The conformations are stabilized by the presence of intramolecular π–π interactions between the naphthalene ring and the six-membered diimide ring of the central naphthalenediimide moiety, with ring centroid-to-centroid distances of 3.5795 (8) Å (A) and 3.5640 (8) Å (B). In the crystal, C—H...O hydrogen bonds link the molecules into infinite supramolecular chains along thecaxis. These chains are interconnected through C—H...π and offset π–π interactions, generating supramolecular nanotubes which are filled by 1,2-dichlorobenzene molecules.

scholarly journals Crystal structure of bis(2-{1-[(E)-(4-fluorobenzyl)imino]ethyl}phenolato-κ2N,O)palladium(II)

2015 ◽  
Vol 71 (4) ◽  
pp. 350-353
Author(s):  
Amalina Mohd Tajuddin ◽  
Hadariah Bahron ◽  
Hamizah Mohd Zaki ◽  
Karimah Kassim ◽  
Suchada Chantrapromma
Keyword(s):  
Crystal Structure ◽  
Schiff Base ◽  
Hydrogen Bonds ◽  
Dihedral Angle ◽  
Title Complex ◽  
Asymmetric Unit ◽  
Schiff Base Ligands ◽  
Bond Lengths ◽  
Square Planar ◽  
Coordination Plane

The asymmetric unit of the title complex, [Pd(C15H13FNO)2], contains one half of the molecule with the PdIIcation lying on an inversion centre and is coordinated by the bidentate Schiff base anion. The geometry around the cationic PdIIcentre is distorted square planar, chelated by the imine N- and phenolate O-donor atoms of the two Schiff base ligands. The N- and O-donor atoms of the two ligands are mutuallytrans, with Pd—N and Pd—O bond lengths of 2.028 (2) and 1.9770 (18) Å, respectively. The fluorophenyl ring is tilted away from the coordination plane and makes a dihedral angle of 66.2 (2)° with the phenolate ring. In the crystal, molecules are linked into chains along the [101] direction by weak C—H...O hydrogen bonds. Weak π–π interactions with centroid–centroid distances of 4.079 (2) Å stack the molecules alongc.

scholarly journals Crystal structure of poly[diaquabis(μ5-benzene-1,3-dicarboxylato)(N,N-dimethylformamide)cadmium(II)disodium(I)]

2017 ◽  
Vol 73 (11) ◽  
pp. 1599-1602 ◽  
Author(s):  
Matimon Sangsawang ◽  
Kittipong Chainok ◽  
Nanthawat Wannarit
Keyword(s):  
Crystal Structure ◽  
Coordination Polymer ◽  
Hydrogen Bonds ◽  
Three Dimensional ◽  
Water Molecules ◽  
Asymmetric Unit ◽  
Carboxylate Groups ◽  
Benzene Rings ◽  
Coordinated Water ◽  
Coordinate Geometry

The title compound, [CdNa2(C8H4O4)2(C3H7NO)(H2O)2]nor [CdNa2(1,3-bdc)2(DMF)(H2O)2]n, is a new CdII–NaIheterobimetallic coordination polymer. The asymmetric unit consists of one CdIIatom, two NaIatoms, two 1,3-bdc ligands, two coordinated water molecules and one coordinated DMF molecule. The CdIIatom exhibits a seven-coordinate geometry, while the NaIatoms can be considered to be pentacoordinate. The metal ions and their symmetry-related equivalents are connectedviachelating–bridging carboxylate groups of the 1,3-bdc ligands to generate a three-dimensional framework. In the crystal, there are classical O—H...O hydrogen bonds involving the coordinated water molecules and the 1,3-bdc carboxylate groups and π–π stacking between the benzene rings of the 1,3-bdc ligands present within the frameworks.

scholarly journals Crystal structure of dichlorido[2-(diphenylphosphanyl)-3,4,5,6-tetrafluorobenzene-1-thiolato-κ2P,S]gold(III)

2015 ◽  
Vol 71 (10) ◽  
pp. m181-m182
Author(s):  
Peter W. R. Corfield ◽  
Mary Bailey
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Dimer Formation ◽  
Polar Solvents ◽  
Square Planar ◽  
Thiolate Ligand ◽  
Cl Atoms ◽  
Low Solubility ◽  
Centrosymmetric Dimers

The title compound, [Au(C18H10F4PS)Cl2], crystallizes as neutral molecules, with the AuIIIatom coordinated by two Cl atoms and by the P and S atoms of the bidentate phosphanyl thiolate ligand, in a slightly distorted square-planar environment. The molecules are linked into centrosymmetric dimersvialong axial Au—Cl bonds of 3.393 (4) Å. This axial Au—Cl distance is longer than is usually seen, although one other example has been given. Dimer formation may explain the unexpectedly low solubility of the compound in common polar solvents. There is also a separate intermolecular Au—F contact of 3.561 (6) Å, but this distance seems too long to be regarded as a bond. Two putative C—H...F hydrogen bonds appear to link the dimers into sheets parallel to (110). There is a short intermolecular F...F contact of 2.695 (10) Å between two dimers related by the twofold axis.

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