622-85-5Relevant academic research and scientific papers
Fragment ion formation in resonance enhanced multiphoton ionization (REMPI) of n-propyl phenyl ether in a supersonic jet
Song, Kyuseok,Van Eijk, Alexander,Shaler, Thomas A.,Morton, Thomas Hellman
, p. 4455 - 4460 (1994)
Resonance enhanced multiphoton ionization (REMPI) mass spectra of different conformational isomers of n-propyl phenyl ether at 30 K give the same fragmentation patterns. Laser REMPI excitation spectra exhibit three principal conformers in a supersonic free jet expansion. The most abundant species in the jet happens also to contribute the longest wavelength 0,0 band. SCF calculations suggest that the lowest energy structure corresponds to a gauche geometry in which all the carbons except that of the methyl group are essentially coplanar with the oxygen. This is confirmed by experimental observation of a predicted blue shift for a prominent vibrational overtone when the propyl group is partially deuterated (β,β-d2 or α,α,γ,γ,γ-ds). Time-of-flight mass spectra of deuterated analogues of each oF three conformers exhibits propene expulsion to yield PhOH?+ and PhOD?+ (the principal fragment ions) in which all seven alkyl hydrogens have become randomized within the chain. REMPI of individual conformer (via intermediacy of the lowest vibrational levels of their excited singlet electronic states) therefore gives the same outcome as does field ionization or electron impact source mass spectra. The predominant decomposition mechanism of the radical cation involves an ion-neutral complex, nPrOPh?+→[iPr+ PhO?], in which the hydrogens of the iPr+ undergo rapid internal transpositions prior to the ultimate decomposition step. Ab initio computations on a model system concur with the experimental inference that this mechanism operates regardless of the conformation of the precursor neutral.
N-ARYL SULFONAMIDE DERIVATIVES AS VACCINE ADJUVANT
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Page/Page column 101-102, (2021/02/26)
Bis-aryl sulfonamide compounds and methods of using those compounds, e.g., in a method of enhancing or prolonging an immune response, are provided. For example, the compounds may be employed with a vaccine and optionally at least one other adjuvant and/or one or more TLR ligands, at least one MAP kinase inhibitor, or any combination thereof.
Ambient Hydrogenation and Deuteration of Alkenes Using a Nanostructured Ni-Core–Shell Catalyst
Beller, Matthias,Feng, Lu,Gao, Jie,Jackstell, Ralf,Jagadeesh, Rajenahally V.,Liu, Yuefeng,Ma, Rui
supporting information, p. 18591 - 18598 (2021/06/28)
A general protocol for the selective hydrogenation and deuteration of a variety of alkenes is presented. Key to success for these reactions is the use of a specific nickel-graphitic shell-based core–shell-structured catalyst, which is conveniently prepared by impregnation and subsequent calcination of nickel nitrate on carbon at 450 °C under argon. Applying this nanostructured catalyst, both terminal and internal alkenes, which are of industrial and commercial importance, were selectively hydrogenated and deuterated at ambient conditions (room temperature, using 1 bar hydrogen or 1 bar deuterium), giving access to the corresponding alkanes and deuterium-labeled alkanes in good to excellent yields. The synthetic utility and practicability of this Ni-based hydrogenation protocol is demonstrated by gram-scale reactions as well as efficient catalyst recycling experiments.
Cobalt-catalyzed alkene hydrogenation by reductive turnover
van der Puyl, Vincent,McCourt, Ruairi O.,Shenvi, Ryan A.
supporting information, (2021/04/19)
Earth abundant metal catalysts hold advantages in cost, environmental burden and chemoselectivity over precious metal catalysts. Differences in reactivity for a given metal center result from ligand field strength, which can promote reaction through either open- or closed-shell carbon intermediates. Herein we report a simple protocol for cobalt-catalyzed alkene reduction. Instead of using an oxidative turnover mechanism that requires stoichiometric hydride, we find a reductive turnover mechanism that requires stoichiometric proton. The reaction mechanism appears to involve coordination and hydrocobaltation of terminal alkenes.
Removal of Alkyl Sulfonates Using DABCO
Corazzata, Kaitlyn,Langston, Alexander,Lee, Elaine C.,Mo, Shunyan,Rose, Peter J.,Snodgrass, Joseph
supporting information, (2021/11/30)
During the route development of a midstage clinical candidate, we were challenged with a presence of alkyl sulfonates, which were identified as potential genotoxic impurities in our active pharmaceutical ingredient (API). As a result, we initiated a development effort to identify a method to remove the alkyl sulfonates that would be amenable for scale-up. Herein, we report our effort toward the development of a general approach using DABCO (1,4-diazabicyclo[2.2.2]octane) to remove alkyl sulfonates that is both efficient and convenient from the bench to scale-up.
Photoredox catalysis on unactivated substrates with strongly reducing iridium photosensitizers
Shon, Jong-Hwa,Kim, Dooyoung,Rathnayake, Manjula D.,Sittel, Steven,Weaver, Jimmie,Teets, Thomas S.
, p. 4069 - 4078 (2021/04/06)
Photoredox catalysis has emerged as a powerful strategy in synthetic organic chemistry, but substrates that are difficult to reduce either require complex reaction conditions or are not amenable at all to photoredox transformations. In this work, we show that strong bis-cyclometalated iridium photoreductants with electron-rich β-diketiminate (NacNac) ancillary ligands enable high-yielding photoredox transformations of challenging substrates with very simple reaction conditions that require only a single sacrificial reagent. Using blue or green visible-light activation we demonstrate a variety of reactions, which include hydrodehalogenation, cyclization, intramolecular radical addition, and prenylationviaradical-mediated pathways, with optimized conditions that only require the photocatalyst and a sacrificial reductant/hydrogen atom donor. Many of these reactions involve organobromide and organochloride substrates which in the past have had limited utility in photoredox catalysis. This work paves the way for the continued expansion of the substrate scope in photoredox catalysis.
Bidentate NHC-Cobalt Catalysts for the Hydrogenation of Hindered Alkenes
Wei, Zeyuan,Wang, Yujie,Li, Yibiao,Ferraccioli, Raffaella,Liu, Qiang
, p. 3082 - 3087 (2020/10/02)
Herein, we report a series of easily accessible bidentate N-heterocyclic carbene (NHC) cobalt catalysts, which enable the hydrogenation of hindered alkenes under mild conditions. The four-coordinated bidentate NHC-Co(II) complexes were characterized by X-ray diffraction, elemental analysis, ESI-HRMS, and magnetic moment measurements, revealing a distorted-tetrahedral geometry and a high-spin configuration of the metal center. The activity of the in situ formed catalytic system, which was obtained from easily available NHC precursors, CoCl2, and NaHBEt3, was identical with those of well-defined NHC-cobalt catalysts. This highlights the potential utility of this reaction system.
Structure-Activity Relationship Studies to Identify Affinity Probes in Bis-aryl Sulfonamides That Prolong Immune Stimuli
Chan, Michael,Lao, Fitzgerald S.,Chu, Paul J.,Shpigelman, Jonathan,Yao, Shiyin,Nan, Jason,Sato-Kaneko, Fumi,Li, Vicky,Hayashi, Tomoko,Corr, Maripat,Carson, Dennis A.,Cottam, Howard B.,Shukla, Nikunj M.
supporting information, p. 9521 - 9540 (2019/11/11)
Agents that safely induce, enhance, or sustain multiple innate immune signaling pathways could be developed as potent vaccine adjuvants or coadjuvants. Using high-throughput screens with cell-based nuclear factor κB (NF-κB) and interferon stimulating response element (ISRE) reporter assays, we identified a bis-aryl sulfonamide bearing compound 1 that demonstrated sustained NF-κB and ISRE activation after a primary stimulus with lipopolysaccharide or interferon-α, respectively. Here, we present systematic structure-activity relationship (SAR) studies on the two phenyl rings and amide nitrogen of the sulfonamide group of compound 1 focused toward identification of affinity probes. The murine vaccination studies showed that compounds 1 and 33 when used as coadjuvants with monophosphoryl lipid A (MPLA) showed significant enhancement in antigen ovalbumin-specific immunoglobulin responses compared to MPLA alone. SAR studies pointed to the sites on the scaffold that can tolerate the introduction of aryl azide, biotin, and fluorescent rhodamine substituents to obtain several affinity and photoaffinity probes which will be utilized in concert for future target identification and mechanism of action studies.
The effect of an acylphosphine ligand on the rhodium-catalyzed hydrosilylation of alkenes
Li, Jiayun,Yang, Chuang,Bai, Ying,Yang, Xiaoling,Liu, Yu,Peng, Jiajian
, p. 7 - 11 (2018/01/01)
We synthesized a series of acylphosphines and investigated the hydrosilylation of alkenes that were catalyzed using RhCl3/acylphosphine. The results indicated that RhCl3/(diphenylphosphino) (phenyl)methanone exhibited higher activity as well as higher levels of β–adduct selectivity.
Sodium borohydride-nickel chloride hexahydrate in EtOH/PEG-400 as an efficient and recyclable catalytic system for the reduction of alkenes
Li, Kaoxue,Liu, Chuanchao,Wang, Kang,Ren, Yang,Li, Fahui
, p. 7761 - 7764 (2018/03/01)
An efficient, safe and one-pot convenient catalytic system has been developed for the reduction of alkenes using NaBH4-NiCl2·6H2O in EtOH/PEG-400 under mild conditions. In this catalytic system, a variety of alkenes (including trisubstituted alkene α-pinene) were well reduced and the Ni catalyst could be recycled.
