35692-88-7Relevant academic research and scientific papers
Vibrational dynamics of N-H, C-D, and C=O modes in formamide
Ha, Jeong-Hyon,Kim, Yung Sam,Hochstrasser, Robin M.
, (2006)
By means of heterodyned two-dimensional IR photon echo experiments on liquid formamide and isotopomers the vibrational frequency dynamics of the N-H stretch mode, the C-D mode, and the C=O mode were obtained. In each case the vibrational frequency correlation function is fitted to three exponentials representing ultrafast (few femtoseconds), intermediate (hundreds of femtoseconds), and slow (many picoseconds) correlation times. In the case of N-H there is a significant underdamped contribution to the correlation decay that was not seen in previous experiments and is attributed to hydrogen-bond librational modes. This underdamped motion is not seen in the C-D or C=O correlation functions. The motions probed by the C-D bond are generally faster than those seen by N-H and C=O, indicating that the environment of C-D interchanges more rapidly, consistent with a weaker C-D...O=C bond. The correlation decays of N-H and C=O are similar, consistent with both being involved in strong H bonding.
Fries rearrangement of aryl formates: A mechanistic study by means of 1H, 2H, and 11B NMR spectroscopy and DFT calculations
Bagno, Alessandro,Kantlehner, Willi,Kress, Ralf,Saielli, Giacomo,Stoyanov, Edmont
, p. 9331 - 9340 (2007/10/03)
(Figure Presented) 1H, 2H, and 11B NMR spectroscopy has been used to study the mechanism of the Fries rearrangement of aryl formates promoted by boron trichloride by monitoring both the substrate and the Lewis acid. DFT calculations were employed to investigate the energetics of several reaction paths and to calculate NMR chemical shifts of key intermediates and products. After the formation of a 1:1 substrate - Lewis acid adduct, the rearrangement proceeds in two steps, beginning with the cleavage of the ester bond and the release of formyl chloride in situ, which, in turn, acts as a formylating agent, introducing an aldehydic functionality into the aromatic ring. The high regioselectivity (only the ortho product is obtained) is also accounted for by the proposed intermolecular, Lewis acid-assisted mechanism.
Amine attack on the carbonyl ligands of the protonated dicyclopentadienyl-bridged diruthenium complex [{(η5-C5H3)2(SiMe 2)2}Ru2(CO)4(μ-H)]+
Ovchinnikov, Maxim V.,Guzei, Ilia A.,Angelici, Robert J.
, p. 691 - 696 (2008/10/08)
Complexes [{(η5-C5H3)2(SiMe 2)2}Ru2(CO)4(μ-H)]+ (1H+BF4-, 1D+TfO-), with a protonated Ru-Ru bond, were prepared by protonation of {(η5-C5H3)2(SiMe 2)2}Ru2(CO)4 (1) with HBF4·Et2O or CF3SO3D. The bridging proton in 1H+ is removed only very slowly by amine bases even though it is thermodynamically acidic (pKaAN = 6.5 (±0.2)). This remarkable kinetic inertness of the bridging proton allows amines (NH3, NH2CH3, NH(CH3)2, morpholine, piperidine, pyrrolidine) to react with 1H+ by attacking the CO ligand to give a formamide (HC(=O)NR2) and the CO-substituted product {(η5-C5H3)2(SiMe 2)2}Ru2(CO)3(NHR2) (2). Thus, protonation of the metal-metal bond in 1H+ promotes reactions of the CO ligand that are not possible in the unprotonated 1. A proposed mechanism for these reactions is supported by kinetic studies of the reaction of 1D+TfO- with morpholine in nitromethane at 20.0 °C, as well as by deuterium-labeling experiments. The molecular structure of {(η5-C5H3)2-(SiMe 2)2}Ru2(CO)3(NH2CH 3) (2f), as determined by an X-ray diffraction investigation, is also presented.
Selective Reactions in the Triazene Series. Part 2. Protodediazoniation of Arenediazonium Salts with Formamide
Threadgill, Michael D.,Gledhill, Adrian P.
, p. 873 - 876 (2007/10/02)
Treatment of performed arenediazonium tetrafluoroborates or arenediazonium trifluoroacetates (formed in situ) with formamide an base effects reduction to the corresponding arene in moderate to good yield in cases where an electron-withdrawing substituent is present on the aromatic ring.Other functionalities remain unaffected.The mechanism of the protodediazoniation is shown to involve transfer of the formyl hydrogen atom to the substrate and may proceed via a 1-aryl-3-formyltriazine.
