5405-41-4Relevant articles and documents
Reaction of ethyl 2,2-dimethoxycyclopropanecarboxylates with m-CPBA. Discovery of two new related degradative processes leading to β-hydroxyacid derivatives
Piccialli, Vincenzo,Graziano, M. Liliana
, p. 93 - 95 (2001)
The reaction of the 3-alkyl-substituted and 3,3-dialkyl-substituted ethyl 2,2-dimethoxycyclopropanecarboxylates 1-3 with m-CPBA in CH2Cl2 leads to the formation of the β-hydroxyacid derivatives 4-6 via two related processes involving the scission of both the C1-C2 and C2-C3 bonds and consequently to the degradation of the original cyclopropane carbon skeleton (extrusion of the C-2 carbon). Cis- and trans-2-ethoxycyclopropanecarboxylic acid ethyl esters 9 and 10, respectively, structurally related to 1-3, are unreactive under the same conditions. A hypothesis explaining the observed reactivity is formulated.
SYNERGISM OF HYDROGENATING CAPACITY IN THE Ni-Pd/Al2O3 SYSTEM
Vedenyapin, A. A.,Giorgadze, N. G.,Murina, I. P.,Yushin, S. V.,Chivadze, G. O.,et al.
, p. 4 - 6 (1990)
In liquid-phase hydrogenation of ethyl acetoacetonate on bimetallic Ni-Pd catalysts supported on Al2O3, the reaction rate increases sharply and passes through a maximum with an increase in the concentration of Pd.The change in the rate of hydrogenation with a change in the composition of the catalysts is not due to a change in the dispersion of the metallic phase in the them or enrichment of their surface with one of the metals.
Effect of the conditions of preparation of asymmetric LaNi3Co2Hn catalysts on their hydrogenating and enantioselective properties
Starodubtseva,Konenko,Fedorovskaya,Klabunovskii,Mordovin
, p. 2452 - 2455 (1989)
1. The conditions of modification (temperature, concentration of R, R-(+)-tartaric acid, solvent) affect the asymmetric properties of tartrate complexes of LaNi3Co2Hn hydrides. 2. The combined effect of NaBr (as a comodifier) and trimethylacetic acid (as a promoter) on the optical yield of the reaction was established.
Synthesis, Structure, and Catalytic Hydrogenation Activity of [NO]-Chelate Half-Sandwich Iridium Complexes with Schiff Base Ligands
Lv, Wen-Rui,Li, Rong-Jian,Liu, Zhen-Jiang,Jin, Yan,Yao, Zi-Jian
, p. 8181 - 8188 (2021/05/26)
A series of N,O-coordinate iridium(III) complexes with a half-sandwich motif bearing Schiff base ligands for catalytic hydrogenation of nitro and carbonyl substrates have been synthesized. All iridium complexes showed efficient catalytic activity for the hydrogenation of ketones, aldehydes, and nitro-containing compounds using clean H2 as reducing reagent. The iridium catalyst displayed the highest TON values of 960 and 950 in the hydrogenation of carbonyl and nitro substrates, respectively. Various types of substrates with different substituted groups afforded corresponding products in excellent yields. All N,O-coordinate iridium(III) complexes 1-4 were well characterized by IR, NMR, HRMS, and elemental analysis. The molecular structure of complex 1 was further characterized by single-crystal X-ray determination.
Coupling Droplet Microfluidics with Ion Mobility Spectrometry for Monitoring Chemical Conversions at Nanoliter Scale
Hartner, Nora T.,Wink, Konstantin,Raddatz, Christian-Robert,Thoben, Christian,Schirmer, Martin,Zimmermann, Stefan,Belder, Detlev
, p. 13615 - 13623 (2021/10/21)
We introduce the coupling of droplet microfluidics and ion mobility spectrometry (IMS) to address the challenges of label-free and chemical-specific detection of compounds in individual droplets. In analogy to the established use of mass spectrometry, droplet-IMS coupling can be also achieved via electrospray ionization but with significantly less instrumental effort. Because IMS instruments do not require high-vacuum systems, they are very compact, cost-effective, and robust, making them an ideal candidate as a chemical-specific end-of-line detector for segmented flow experiments. Herein, we demonstrate the successful coupling of droplet microfluidics with a custom-built high-resolution drift tube IMS system for monitoring chemical reactions in nL-sized droplets in an oil phase. The analytes contained in each droplet were assigned according to their characteristic ion mobility with limit of detections down to 200 nM to 1 μM and droplet frequencies ranging from 0.1 to 0.5 Hz. Using a custom sheath flow electrospray interface, we have further achieved the chemical-specific monitoring of a biochemical transformation catalyzed by a few hundred yeast cells, at single droplet level.
Concise Synthesis of (+)-[13C4]-Anatoxin-a by Dynamic Kinetic Resolution of a Cyclic Iminium Ion
Chen, Karen Y.,Lacharity, Jacob J.,Mailyan, Artur K.,Zakarian, Armen
supporting information, p. 11364 - 11368 (2020/05/18)
An asymmetric total synthesis of [13C4]-anatoxin-a ([13C4]-1) has been developed from commercially available ethyl [13C4]-acetoacetate ([13C4]-15). The unique requirements associated with isotope incorporation inspired a new, robust, and highly scalable route, providing access to 0.110 g of this internal standard for use in the detection and precise quantification of anatoxin-a in freshwater. A highlight of the synthesis is a method that leverages a cyclic iminium ion racemization to achieve dynamic kinetic resolution in an enantioselective Morita–Baylis–Hillman (MBH) cyclization.
Catalytic hydrogenation of carbonyl and nitro compounds using an [: N, O] -chelate half-sandwich ruthenium catalyst
Yao, Zi-Jian,Zhu, Jing-Wei,Lin, Nan,Qiao, Xin-Chao,Deng, Wei
, p. 7158 - 7166 (2019/06/13)
A series of N,O-chelate half-sandwich ruthenium complexes for both carbonyl and nitro compound hydrogenation have been synthesized based on β-ketoamino ligands. All complexes exhibited high activity for the catalytic hydrogenation of a series of ketones and nitroarenes with molecular H2 as the reducing reagent in aqueous medium. Consequently, the catalytic system showed the catalytic TON values of 950 for 1-phenylethanol in acetophenone hydrogenation and 1960 for 1-chloro-4-nitrobenzene in p-chloroaniline hydrogenation. Good catalytic activity was displayed for various kinds of substrates with either electron-donating or electron-withdrawing groups. The neutral ruthenium complexes 1-4 were fully characterized using NMR, IR, and elemental analysis. Molecular structures of complexes 2 and 4 were further confirmed using single-crystal X-ray diffraction analysis.
Cobalt-Catalyzed Alkoxycarbonylation of Epoxides to β-Hydroxyesters
Xu, Jian-Xing,Wu, Xiao-Feng
, p. 9907 - 9912 (2019/08/26)
Herein, we developed a new and practical catalytic system for the carbonylative synthesis of β-hydroxyesters. By using simple, cheap, and air-stable cobalt(II) bromide as the catalyst, combined with pyrazole and catalytic amount of manganese, active cobalt complex can be generated in situ and can catalyze various epoxides to give the corresponding β-hydroxyesters in moderate to excellent yields. Mechanism studies indicate that pyrazole plays a crucial role in this reaction. Moreover, with the addition of the catalytic amount of manganese, the active cobalt catalyst can be regenerated, which provides a possibility for reusing the cobalt catalyst.
Iridium-catalyzed efficient reduction of ketones in water with formic acid as a hydride donor at low catalyst loading
Liu, Ji-Tian,Yang, Shiyi,Tang, Weiping,Yang, Zhanhui,Xu, Jiaxi
supporting information, p. 2118 - 2124 (2018/05/24)
A highly efficient and chemoselective transfer hydrogenation of ketones in water has been successfully achieved with our newly developed catalyst. Simple ketones, as well as α- or β-functionalized ketones, are readily reduced. Formic acid is used as a traceless hydride source. At very low catalyst loading (S/C = 10:000 in most cases; S/C = 50:000 or 100:000 in some cases), the iridium catalyst is impressively efficient at reducing ketones in good to excellent yields. The TOF value can be as high as up to 26:000 mol mol-1 h-1. A variety of functional groups are well tolerated, for example, heteroaryl, aryloxy, alkyloxy, halogen, cyano, nitro, ester, especially acidic methylene, phenol and carboxylic acid groups.
Ruthenium(II) Complexes of 4′-(Aryl)-2,2′:6′,2′′-terpyridyl Ligands as Simple Catalysts for the Transfer Hydrogenation of Ketones
Maity, Apurba,Sil, Amit,Patra, Sanjib K.
, p. 4063 - 4073 (2018/09/11)
A series of cationic [Ru(L)(PPh3)2Cl]+ (1–3) and neutral [Ru(L)(PPh3)Cl2] (4–6) RuII complexes were synthesized by reacting [RuCl2(PPh3)2] with 4′-(aryl)-2,2′:6′,2′′-terpyridyl-based ligands (L1–L3) with various aryl groups (tolyl, phenyl and 4-fluorophenyl). The synthesized RuII complexes were unambiguously characterized by various spectroscopic techniques such as FTIR and multinuclear NMR spectroscopy as well as HRMS. The neutral complexes (4–6) were also structurally characterized by single-crystal X-ray diffraction studies. Photophysical and electrochemical studies of the RuII complexes were performed to elucidate the effects of the 4′-aryl substituents of L1–L3. These RuII complexes show good catalytic activities in the transfer hydrogenation (TH) of ketones with a wide substrates scope in 2-propanol under reflux. An optimization study revealed that the neutral RuII complexes are better catalysts than the cationic RuII complexes for TH reactions. Finally, [Ru(L1)(PPh3)2H]+ (7) with a [RuII–H] functionality was successfully synthesized and isolated and is proposed as the catalytically active species. A control experiment with the [RuII–H] complex in the absence of base was performed to establish the mechanism for the catalytic TH of ketones.
