437-30-9Relevant academic research and scientific papers
Carbon's Three-Center, Four-Electron Tetrel Bond, Treated Experimentally
Karim, Alavi,Schulz, Nils,Andersson, Hanna,Nekoueishahraki, Bijan,Carlsson, Anna-Carin C.,Sarabi, Daniel,Valkonen, Arto,Rissanen, Kari,Gr?fenstein, Jürgen,Keller, Sandro,Erdélyi, Máté
supporting information, p. 17571 - 17579 (2019/01/04)
Tetrel bonding is the noncovalent interaction of group IV elements with electron donors. It is a weak, directional interaction that resembles hydrogen and halogen bonding yet remains barely explored. Herein, we present an experimental investigation of the
Stabilities of trityl-protected substrates: The wide mechanistic spectrum of trityl ester hydrolyses
Horn, Markus,Mayr, Herbert
supporting information; experimental part, p. 7469 - 7477 (2010/09/11)
Ionization rates of para-substituted triphenylmethyl (trityl) acetates, benzoates, and para-nitrobenzoates have been determined in aqueous acetonitrile and aqueous acetone at 25 °C. Conventional and stoppedflow techniques have been used to evaluate rate constants ranging from 1.38 × 10-5 to 2.15 × 102S-1 by conductimetry and photospectrometry methods. The varying stabilities of the differently substituted tritylium ions account for a gradual change of reaction mechanism. Poorly stabilized carbocations are generated slowly by the ionization of their covalent precursors and trapped fast by water. Better stabilized carbocations are generated more rapidly and accumulate, so that ionization and trapping by water can be observed as separate steps in a single experiment. Finally, highly stabilized tritylium ions do not react with water, and only the rates of their formation could be measured. The ionization rate constants correlate linearly with Winstein's ionizing powers Y; the low slopes (0.17 + parameters is excellent for symmetrically substituted tritylium derivatives, deviations for unsymmetrically substituted systems are observed. The failing rate-equilibrium relationship between the rates of ionizations (log kion) and the stabilities of the carbocations in aqueous solution (pKR+) may be explained by the late " development of resonance between a p-amino group and the carbocationic center of the tritylium ion during the ionization process.
N-tritylhydroxylamines: Preparations, structures, base strengths, and reactions with nitrous acid and perchloric acid
Canle L, Moises,Clegg, William,Demirtas, Ibrahim,Elsegood, Mark R.J.,Haider, Johanna,Maskill, Howard,Miatt, Peter C.
, p. 1742 - 1747 (2007/10/03)
N-Trityl, N-(4-methoxytrityl), N-(4,4′-dimethoxytrityl), and N-(4,4′,4″-trimethoxytrityl) derivatives of hydroxylamine, O-methylhydroxylamine, and O-benzylhydroxylamine have been prepared and characterised. Additionally, N,O-ditrityl- and N,O-bis(4,4′-dimethoxytrityl)-hydroxylamines have been made, and the X-ray crystal structure of the former has been determined. The pKa value of O-benzylhydroxylammonium in water (6.2) and of its N-trityl analogue in aqueous acetonitrile (7.5) have been measured. The N-tritylhydroxylamines all decompose under aqueous acidic conditions to give the corresponding trityl alcohols, and rate constants for uncatalysed and hydronium ion catalysed reactions of N-(4,4′-dimethoxytrityl)-O-methylhydroxylamine have been measured by stopped flow kinetics at 25 °C. This compound compares in reactivity with N-alkyl-N-(4,4′-dimethoxytrityl)amines rather than with 4,4′-dimethoxytritylamine. Attempted nitrosation of N-tritylhydroxylamine and its O-alkyl derivatives gave trityl alcohol, the intermediate N-nitroso compound being detectable but too unstable to isolate. From N-trityl-O-benzylhydroxylamine, attempted nitrosation led to the formation of triphenylmethane in addition to trityl alcohol, benzyl alcohol, and trityl benzyl ether. The mildly acidic conditions used for attempted nitrosation of methoxy-substituted N-tritylhydroxylamines led to deamination before addition of the nitrosating agent.
4,4′-Dimethoxytrityl and 4,4′,4″-trimethoxytrityl as protecting groups for amino functions; selectivity for primary amino groups and application in 15N-labelling
Henderson, Alistair P.,Riseborough, Jane,Bleasdale, Christine,Clegg, William,Elsegood, Mark R. J.,Golding, Bernard T.
, p. 3407 - 3413 (2007/10/03)
4,4′-Dimethoxytrityl tetrafluoroborate (DMT+ BF4-) and 4,4′,4″-trimethoxytrityl tetrafluoroborate (TMT+ BF4-) are useful reagents for protecting primary and some secondary amines. Protected amines are obtained either by reaction of DMT+ BF4- or TMT+ BF4- with the amine or by alkylating DMT- or TMT-amine (available from DMT+ BF4- and TMT+ BF4- by treatment with ammonia). Alkylation of DMT- or TMT-amine stops after monoalkylation. Deprotection of the alkylated DMT- and TMT-amine is achieved by treatment with an acid of appropriate molarity (e.g. 0.1 M HCl in 1:1 tetrahydrofuran-water for TMT-amines). The value of the methodology described is illustrated by a synthesis of (15NH2) adenosine. X-Ray molecular structures of one DMT and two TMT derivatives are reported.
CARBON-CARBON BOND FORMATION BY COORDINATION OF CARBOCATIONS WITH CARBANIONS.
Arnett, Edward M.,Troughton, E. B.
, p. 3299 - 3302 (2007/10/02)
Direct attack of resonance-stabilized carbenium ions and carbanions can be regulated to provide a wide range of rates and equilibria for the study of carbon-carbon bond formation.
