100-58-3Relevant articles and documents
Scalable Continuous Synthesis of Grignard Reagents from in Situ-Activated Magnesium Metal
Deitmann, Eva,G?ssl, Lars,Hofmann, Christian,L?b, Patrick,Menges-Flanagan, Gabriele
, p. 315 - 321 (2020)
The continuous synthesis of Grignard reagents has been investigated under continuous processing conditions using Mg turnings at variable liquid throughputs and concentrations. A novel process window easily accessible through continuous processing was employed, namely, using a large molar access of Mg turnings within the reactor and achieving Mg activation by mechanical means. A laboratory and a 10-fold-increased pilot-scale reactor setup were built and evaluated, including integrated inline analytics via ATR-IR measurements. The main goal of this work was to explore the full potential of classic Grignard reagent formation through the use of scalable flow chemistry and to allow for fast and safe process optimization. It was found that on both the laboratory and pilot scales, full conversion of the employed halides could be achieved with a single passage through the reactor. Furthermore, Grignard reagent yields of 89-100% were reached on the laboratory scale.
Preparation of Grignard reagents from magnesium metal under continuous flow conditions and on-line monitoring by NMR spectroscopy
Goldbach, Michel,Danieli, Ernesto,Perlo, Juan,Kaptein, Bernard,Litvinov, Victor M.,Blümich, Bernhard,Casanova, Federico,Duchateau, Alexander L.L.
, p. 122 - 125 (2016)
A convenient method for the classical preparation of Grignard reagents from aryl halides and magnesium using a fluidized bed reactor under continuous flow conditions was developed. The process was combined with quenching of the Grignard reagent by CO2 as a model reaction performed using a second flow reactor. The formation and quenching of the reagent was monitored by on-line 1H NMR spectroscopy. The combination of continuous flow operation for Grignard reagents with reaction monitoring by on-line NMR spectroscopy allows one to quickly optimize the working conditions.
Formation of phenylmagnesium halides in toluene
Simuste, Hannes,Panov, Dmitri,Tuulmets, Ants,Nguyen, Binh T.
, p. 3061 - 3066 (2005)
Formation reactions of phenylmagnesium chloride and bromide in toluene in the presence of one or two equivalents of diethyl ether or THF were investigated kinetically. Also, the reaction in diethyl ether and in chlorobenzene was addressed. Kinetic features of the reactions are similar to those found previously for the formation of alkylmagnesium halides in toluene and consist of rapid formation of a disolvated Grignard reagent followed by a slower formation of a monosolvated reagent. The latter is able of catalyzing the conversion of different halides into Grignard reagents. However, the contribution of Wurtz-type side reactions is considerable except when THF is used in toluene. Involving the kinetic data and the activation parameters some details of the reaction mechanism were discussed.
Palladium-Catalyzed Cross-Coupling of Arenediazonium Salts with Organoindium or Organobismuth Reagents
Riemer, Nastja,Coswig, Christin,Shipman, Mike,Schmidt, Bernd
, p. 2427 - 2431 (2018)
Arylindium and isolated triarylbismuth compounds generated in situ react as nucleophiles with arenediazonium salts in palladium-catalyzed cross-coupling reactions to give substituted biphenyls.
Nickel-Catalyzed Alkyl-Alkyl Cross-Electrophile Coupling Reaction of 1,3-Dimesylates for the Synthesis of Alkylcyclopropanes
Chen, Pan-Pan,Hong, Xin,Jarvo, Elizabeth R.,McGinnis, Tristan M.,Sanford, Amberly B.,Thane, Taylor A.
, (2020)
Cross-electrophile coupling reactions of two Csp3-X bonds remain challenging. Herein we report an intramolecular nickel-catalyzed cross-electrophile coupling reaction of 1,3-diol derivatives. Notably, this transformation is utilized to synthesize a range of mono- and 1,2-disubstituted alkylcyclopropanes, including those derived from terpenes, steroids, and aldol products. Additionally, enantioenriched cyclopropanes are synthesized from the products of proline-catalyzed and Evans aldol reactions. A procedure for direct transformation of 1,3-diols to cyclopropanes is also described. Calculations and experimental data are consistent with a nickel-catalyzed mechanism that begins with stereoablative oxidative addition at the secondary center.
Design, synthesis and antifungal activity of novel selenochroman-4-one derivatives
Xu, Hang,Hu, Yu-Kun,Guo, Meng-Bi,Huang, Ai-Su,Su, Xin,Guo, Chun
, p. 2455 - 2463 (2017)
A series of novel selenochroman-4-one derivatives bearing semicarbazone or nitrogen heterocycle was designed, synthesized, tested antifungal activity and characterized via 1H-NMR, 13C-NMR, and HRMS. The design of the compounds is based on the principle of molecule hybrid and bioisosterism. We aimed at attaching semicarbazones or nitrogen heterocycle to the selenochroman-4-one for enhancing antifungal activity. The antifungal activity of target compounds was evaluated using the microdilution broth method in vitro test. Bioassay results indicated that some of the derivatives displayed good fungistatic activity on Candida zeylanoides, Candida albicans, Cryptococcus neoformans, resistant to fluconazole strain 103 (Candida albicans), resistant to fluconazole strain 100 (Candida albicans) and strain SC5314 (Candida albicans). All the compounds exhibit antifungal activities against the tested funguses in different levels, among them, 7 compounds of antifungal activity against several funguses is better than that of the control drug fluconazole. Based on the results, preliminary structure activity relationships (SARs) were summarized to serve as a foundation for further investigation.
Formation of Transient Anionic Metal Clusters in Palladium/Diene-Catalyzed Cross-Coupling Reactions
Kolter, Marlene,Koszinowski, Konrad
, p. 13376 - 13384 (2019)
Despite their considerable practical value, palladium/1,3-diene-catalyzed cross-coupling reactions between Grignard reagents RMgCl and alkyl halides AlkylX remain mechanistically poorly understood. Herein, we probe the intermediates formed in these reactions by a combination of electrospray-ionization mass spectrometry, UV/Vis spectroscopy, and NMR spectroscopy. According to our results and in line with previous hypotheses, the first step of the catalytic cycle brings about transmetalation to afford organopalladate anions. These organopalladate anions apparently undergo SN2-type reactions with the AlkylX coupling partner. The resulting neutral complexes then release the cross-coupling products by reductive elimination. In gas-phase fragmentation experiments, the occurrence of reductive eliminations was observed for anionic analogues of the neutral complexes. Although the actual catalytic cycle is supposed to involve chiefly mononuclear palladium species, anionic palladium nanoclusters [PdnR(DE)n]?, (n=2, 4, 6; DE=diene) were also observed. At short reaction times, the dinuclear complexes usually predominated, whereas at longer times the tetra- and hexanuclear clusters became relatively more abundant. In parallel, the formation of palladium black pointed to continued aggregation processes. Thus, the present study directly shows dynamic behavior of the palladium/diene catalyst system and degradation of the active catalyst with increasing reaction time.
Ni-Catalyzed C(sp2)-H alkylation ofN-quinolylbenzamides using alkylsilyl peroxides as structurally diverse alkyl sources
Kano, Taichi,Maruoka, Keiji,Matsumoto, Akira,Sakurai, Shunya,Tsuzuki, Saori
supporting information, p. 7942 - 7945 (2021/08/17)
A Ni-catalyzed direct C-H alkylation ofN-quinolylbenzamides using alkylsilyl peroxides as alkyl-radical precursors is described. The reaction forms a new C(sp3)-C(sp2) bondviathe selective cleavage of both C(sp3)-C(sp3) and C(sp2)-H bonds. This transformation shows a high functional-group tolerance and, due to the structural diversity of alkylsilyl peroxides, a wide range of alkyl chains including functional groups and complex structures can be introduced at theortho-position of readily availableN-quinolylbenzamide derivatives. Mechanistic studies suggest that the reaction involves a radical mechanism.
Room-Temperature Palladium(II)-Catalyzed Direct 2-Arylation of Indoles with Tetraarylstannanes
Liu, Yuxia,Wang, Chao,Huang, Linjuan,Xue, Dong
supporting information, p. 1613 - 1618 (2020/09/15)
A palladium(II)-catalyzed direct 2-arylation of indoles by tetraarylstannanes with oxygen (balloon) as the oxidant at room temperature has been developed. Various tetraarylstannanes can be employed as aryl sources for 2-arylation of indoles in up to 89% yield, providing a practical and efficient catalytic protocol for accessing 2-arylindoles.
Structure-Activity Relationship Studies of α-Ketoamides as Inhibitors of the Phospholipase A and Acyltransferase Enzyme Family
Zhou, Juan,Mock, Elliot D.,Al Ayed, Karol,Di, Xinyu,Kantae, Vasudev,Burggraaff, Lindsey,Stevens, Anna F.,Martella, Andrea,Mohr, Florian,Jiang, Ming,Van Der Wel, Tom,Wendel, Tiemen J.,Ofman, Tim P.,Tran, Yvonne,De Koster, Nicky,Van Westen, Gerard J.P.,Hankemeier, Thomas,Van Der Stelt, Mario
, p. 9340 - 9359 (2020/10/19)
The phospholipase A and acyltransferase (PLAAT) family of cysteine hydrolases consists of five members, which are involved in the Ca2+-independent production of N-acylphosphatidylethanolamines (NAPEs). NAPEs are lipid precursors for bioactive N-acylethanolamines (NAEs) that are involved in various physiological processes such as food intake, pain, inflammation, stress, and anxiety. Recently, we identified α-ketoamides as the first pan-active PLAAT inhibitor scaffold that reduced arachidonic acid levels in PLAAT3-overexpressing U2OS cells and in HepG2 cells. Here, we report the structure-activity relationships of the α-ketoamide series using activity-based protein profiling. This led to the identification of LEI-301, a nanomolar potent inhibitor for the PLAAT family members. LEI-301 reduced the NAE levels, including anandamide, in cells overexpressing PLAAT2 or PLAAT5. Collectively, LEI-301 may help to dissect the physiological role of the PLAATs.
