15290-24-1Relevant academic research and scientific papers
Nitro-substituted aryl lithium compounds in microreactor synthesis: Switch between kinetic and thermodynamic control
Nagaki, Aiichiro,Kim, Heejin,Yoshida, Jun-ichi
supporting information; experimental part, p. 8063 - 8065 (2010/01/16)
Be quick or take your time, depending on your goal: A microflow method for the generation and transformation of o-, m-, and p-nitro-substituted aryl lithium compounds enabled the selective use of either the kinetically or the thermodynamically preferred intermediate. In the example pictured, a residence time of 0.06 s at -48 °C led to the formation of 1, whereas 2 was obtained exclusively when the residence time was extended to 63 s.
A mild and efficient protocol for the catalytic silylation of aryl bromides
Goossen,Ferwanah
, p. 1801 - 1803 (2007/10/03)
New catalyst systems were developed which facilitate palladium-catalyzed silylation of various functionalized aryl and heteroaryl bromides with hexamethyldisilane under unprecedented mild conditions. The use of two different sets of ligands and bases for electron-rich and electron-poor substrates, respectively, is crucial for achieving excellent product selectivities at 100 °C and atmospheric pressure. For electron-rich substrates, diphenyl-2'-pyridylphosphine in combination with K2CO3 gives the best results, whereas for electron-poor substrates, 2-(di-t-butylphosphino)biphenyl/KF is preferred. Even base-sensitive arylsilanes, which are inaccessible by the traditional routes via organolithium species or Grignard reagents, can be prepared in a single step and high yields.
Retinobenzoic Acids. 5. Retinoidal Activities of Compounds Having a Trimethylsilyl or Trimethylgermyl Group(s) in Human Promyelocytic Leukemia Cells HL-60
Yamakawa, Takeru,Kagechika, Hiroyuki,Kawachi, Emiko,Hashimoto, Yuichi,Shudo, Koichi
, p. 1430 - 1437 (2007/10/02)
The retinoidal activities of trimethylsilyl or trimethylgermyl-containing retinobenzoic acids are discussed on the basis of differentiation-inducing activity on human promyelocytic leukemia cells HL-60.Compounds with a trimethylsilyl or trimethylgermyl gr
GAS-PHASE REACTIONS OF ARYLSILANES WITH NITRATING CATIONS. NITRATION vs. NITRODESILYLATION
Attina, Marina,Cacace, Fulvio,Ricci, Andreina
, p. 217 - 224 (2007/10/02)
The mass spectrometric and radiolytic study of the reaction of (MeNO3)H(+) with phenyl- and tolyl-trimethylsilanes has allowed to demonstrate the first example of gas-phase aromatic nitro desilylation.The process accompanies predominant nitration of the substrate, the ratio of the two channels ranging from ca. 1:2 in the case of C6H5Si(CH3)3 to ca. 1:4 in the case of m-CH3C6H4Si(CH3)3, measured in CH4 at 37 deg C, 750 Torr.Nitro desilylation of trimethylsilanes gives nitrotoluenes in which the NO2 group is not exclusively bound to the ring position formerly occupied by the SiMe3 group.Such observation bears directly on an unsettled problem concerning the detailed course of aromatic substitution by gaseous (RNO3)H(+) ions, in that it favours the classical pathway, involving intermediacy of arenium ions, excluding the alternative, concerted mechanism.The gas-phase nitration of C6H5Si(CH3)3 is characterized by a kPhSiMe3/kPhH ratio of 6.5 +/- 0.5 and by a 25percent ipso, 28percent ortho, 23percent meta, 24percent para orientation.These data can be combined with the known ρ constant of the reaction to derive the SiMe3 substituent constants, i. e. ?m(+) = -0.17 and ?p(+) = -0.25.The mechanistic features of the gas-phase reactions of (MeNO3)H(+) with phenylsilanes are discussed, and compared with relevant data from condensed-phase studies.
