931-50-0Relevant articles and documents
Visible-Light-Promoted Iron-Catalyzed C(sp2)–C(sp3) Kumada Cross-Coupling in Flow
Wei, Xiao-Jing,Abdiaj, Irini,Sambiagio, Carlo,Li, Chenfei,Zysman-Colman, Eli,Alcázar, Jesús,No?l, Timothy
supporting information, p. 13030 - 13034 (2019/07/18)
A continuous-flow, visible-light-promoted method has been developed to overcome the limitations of iron-catalyzed Kumada–Corriu cross-coupling reactions. A variety of strongly electron rich aryl chlorides, previously hardly reactive, could be efficiently coupled with aliphatic Grignard reagents at room temperature in high yields and within a few minutes’ residence time, considerably enhancing the applicability of this iron-catalyzed reaction. The robustness of this protocol was demonstrated on a multigram scale, thus providing the potential for future pharmaceutical application.
Chromium(II)-Catalyzed Diastereoselective and Chemoselective Csp2-Csp3 Cross-Couplings Using Organomagnesium Reagents
Li, Jie,Ren, Qianyi,Cheng, Xinyi,Karaghiosoff, Konstantin,Knochel, Paul
supporting information, p. 18127 - 18135 (2019/11/19)
A simple protocol for performing chromium-catalyzed highly diastereoselective alkylations of arylmagnesium halides with cyclohexyl iodides at ambient temperature has been developed. Furthermore, this ligand-free CrCl2 enables efficient electrophilic alkenylations of primary, secondary, and tetiary alkylmagnesium halides with readily available alkenyl acetates. Moreover, this chemoselective C-C coupling reaction with stereodefined alkenyl acetates proceeds in a stereoretentive fashion. A wide range of functional groups on alkyl iodides and alkenyl acetates are well tolerated, thus furnishing functionalized Csp2-Csp3 coupling products in good yields and high diastereoselectivity. Detailed mechanistic studies suggest that the in situ generated low-valent chromium(I) species might be the active catalyst for these Csp2-Csp3 cross-couplings.
Probing the Delicate Balance between Pauli Repulsion and London Dispersion with Triphenylmethyl Derivatives
R?sel, S?ren,Becker, Jonathan,Allen, Wesley D.,Schreiner, Peter R.
supporting information, p. 14421 - 14432 (2018/10/26)
The long-known, ubiquitously present, and always attractive London dispersion (LD) interaction was probed with hexaphenylethane (HPE) derivatives. A series of all-meta hydrocarbyl [Me, iPr, tBu, Cy, Ph, 1-adamantyl (Ad)]-substituted triphenylmethyl (TPM) derivatives [TPM-H, TPM-OH, (TPM-O)2, TPM?] was synthesized en route, and several derivatives were characterized by single-crystal X-ray diffraction (SC-XRD). Multiple dimeric head-to-head SC-XRD structures feature an excellent geometric fit between the meta-substituents; this is particularly true for the sterically most demanding tBu and Ad substituents. NMR spectra of the iPr-, tBu-, and Cy-derived trityl radicals were obtained and reveal, together with EPR and UV-Vis spectroscopic data, that the effects of all-meta alkyl substitution on the electronic properties of the trityl scaffold are marginal. Therefore, we concluded that the most important factor for HPE stability arises from LD interactions. Beyond all-meta tBu-HPE we also identified the hitherto unreported all-meta Ad-HPE. An intricate mathematical analysis of the temperature-dependent dissociation constants allowed us to extract δGd298(exptl) = 0.3(5) kcal mol-1 from NMR experiments for all-meta tBu-HPE, in good agreement with previous experimental values and B3LYP-D3(BJ)/def2-TZVPP(C-PCM) computations. These computations show a stabilizing trend with substituent size in line with all-meta Ad-HPE (δGd298(exptl) = 2.1(6) kcal mol-1) being more stable than its tBu congener. That is, large, rigid, and symmetric hydrocarbon moieties act as excellent dispersion energy donors. Provided a good geometric fit, they are able to stabilize labile molecules such as HPE via strong intramolecular LD interactions, even in solution.
Nickel-Catalyzed Cross-Coupling of Functionalized Organo manganese Reagents with Aryl and Heteroaryl Halides Promoted by 4-Fluorostyrene
Benischke, Andreas D.,Desaintjean, Alexandre,Juli, Thomas,Cahiez, Gérard,Knochel, Paul
supporting information, p. 5396 - 5412 (2017/12/14)
A catalytic system consisting of Ni(acac) 2 (5 mol%) and 4-fluorostyrene (20 mol%) allows a convenient cross-coupling of functionalized organomanganese reagents with a variety of aryl and heteroaryl halides leading to polyfunctionalized diaryl- and arylheteroarylmethane derivatives.
SYNTHESIS METHOD FOR L-CYCLIC ALKYL AMINO ACID AND PHARMACEUTICAL COMPOSITION HAVING THEREOF
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Paragraph 0070-0071; 0080, (2016/11/17)
A synthesis method for L-cyclic alkyl amino acid and a pharmaceutical composition having the said amino acid are provide in the present disclosure provides. The synthesis method comprises: step A.) preparing a cyclic alkyl keto acid or a cyclic alkyl keto acid salt having Structural Formula (I) or Structural Formula (II), and step B.) mixing the cyclic alkyl keto acid or the cyclic alkyl keto acid salt with ammonium formate, a leucine dehydrogenase, a formate dehydrogenase and a coenzyme NAD+, and carrying out a reductive amination reaction to generate the L-cyclic alkyl amino acid, wherein the Structural Formula (I) is where n1≧1, m1≧0 and the M1 is H or a monovalent cation; the Structural Formula (II) is where n2≧0, m2≧0, the M2 is H or a monovalent cation, an amino acid sequence of the leucine dehydrogenase is SEQ ID No.1.
PYRIDO [4,3-B] INDOLES AND METHODS OF USE
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Page/Page column 85-86, (2010/11/17)
New heterocyclic compounds that may be used to modulate a histamine receptor in an individual are described. Pyrido[4,3-b]indoles are described, as are pharmaceutical compositions comprising the compounds and methods of using the compounds in a variety of therapeutic applications, including the treatment of a cognitive disorder, psychotic disorder, neurotransmitter-mediated disorder and/or a neuronal disorder.
Intermediate for the production of 1-[2-dimethylamino-1-(4-methoxyphenyl)-ethyl]-cyclohexanol
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Page 9, (2008/06/13)
Processes for the preparation of Venlafaxine (IX) via the novel epoxy-nitrile intermediate (I), which when subjected to hydrogenation forms compound (X), and may subsequently be reduced to yield the desired product (IX). The epoxy-nitrile intermediate (I) itself may be synthesised via various alternative reaction strategies, from a range of starting materials. E.g. 4-methoxy-benzaldehyde (VI), upon treatment with cyclohexyl magnesium bromide yields compound (V). This in turn may be oxidised to yield compound (III), which forms compound (II) on treatment with an α-keto-halogenation agent. Cyanation of compound (II), then yields the desired epoxy nitrile intermediate (I), from which Venlafaxine (IX) may be synthesised.
Efficient light harvesting by sequential energy transfer across aggregates in polymers of finite conjugational segments with short aliphatic linkages
Peng,Chen,Fann
, p. 11388 - 11397 (2007/10/03)
Interactions between lumophores have a critical influence on the photophysical properties of conjugated polymers. We synthesized a new series of light-harvesting polymers (poly-DSBs, I-IV) of dialkyloxy- or dialkyl- substituted distyrylbenzene (the substituents being methoxy, 2-ethylhexyloxy, and cyclohexyl) with short aliphatic linkage (methylene or ethylene) and examined the effects of interactions between lumophores and of chemical structures on the absorption, emission, and excitation spectra. The proximity between distyrylbenzene lumophores was shown to be critical to the interactions between lumophores and to the energy-transfer processes. In concentrated solutions and solid films, intermolecular aggregates exist resulting from different extents of interactions between lumophores and are found to involve at least three species: loose, compact, and the most aligned aggregates as observed by photoluminescence and excitation spectroscopies. We also found, for the first time, sequential energy transfer from individual lumophores to the most compact, aligned aggregates via the looser intermolecular aggregates, as observed directly by time-resolved fluorescence spectroscopy. Such a process mimics energy transfer in photosynthesis units and is so efficient such that the fluorescence color can be red-shifted drastically by the presence of comparatively few aggregates and that the light evolved from concentrated solutions and films of poly-DSBs I-IV is entirely or almost the aggregation emission. Although the sequential energy-transfer process in fully conjugated electro-/photoluminescent polymers due to inhomogenity other than distributed conjugation lengths has never been directly observed at room temperature, we suggest that events similar to those observed in poly-DSBs in conjugated polymers could occur but on a much shorter time scale, i.e., a few picoseconds.
Thermochemical Bond Dissociation Energies of Carbon-Magnesium Bonds
Holm, Torkil
, p. 464 - 467 (2007/10/02)
The heats of formation of 29 alkylmagnesium bromides, isobutyl bromide, and neopentyl bromide have been determined, and bond dissociation energies have been derived for the Grignard reagents.For saturated alkyl derivatives the C-Mg bond strength decreases with an increasing number of β-hydrogens in the series methyl, neopentyl, isobutyl, butyl, ethyl, 1-ethylpropyl, 1-methylpropyl, isopropyl, and t-butyl.Bonding in alkyl bromides and alkylmagnesium bromides is discussed.
