Xn:Harmful;
83-33-0Relevant academic research and scientific papers
Photoinduced Double Addition of Acetylene to 3-Oxocyclopent-1-ene-1-carbonitrile or 3-Oxocyclopent-1-enyl Acetate Leading to 2,3-Dihydro-1H-inden-1-one and Other Rearranged Products
Cavazza, Marino,Guella, Graziano,Pietra, Francesco
, p. 1608 - 1615 (1988)
UV Irradiation of 3-oxocyclopent-1-enyl acetate (17) and acetylene in MeCN at 0 deg C gives, besides the product of normal enone-alkyne cycloaddition (cis-4-oxobicyclohept-6-en-1-yl acetate, 18) and its product of oxa-di-?-methane rearrangement (5-oxotricyclo2,7>hept-2-yl acetate, 19), unexpected products of further addition of a molar equivalent of acetylene.These are indanone (= 2,3-dihydro-1H-inden-1-one, 16), in 21percent yield, cis-1-cisoid-1,2-cis-2- (20) and cis-1-transoid-1,2-cis-2,7-oxotricyclo2,5>non-3-en-1-yl acetate (21), 4-oxo-7-'exo'-vinyltricyclo2,6>hept-2-yl acetate (22), cis-4-oxo-6 -'endo'- (23) and cis-4-oxo-6-'exo'-vinylbicyclohept-1-yl acetate (24), and cis-4-oxo-7-'exo'-vinylbicyclohept-1-yl acetate (25).At least in part, indanone must be formed via intermediates 20 and 21.In fact, on heating a 9:1 mixture 20/21, indanone is obtained quantitatively.With 3-oxocyclopent-1-ene-1-carbonitrile (15) in place of 17, indanone is formed in lower (8percent) yield besides much tars.
Solid state asymmetric synthesis of chiral crystals of 5- and 7-membered ring ketones
Xu, Xianzhu,Wang, Peng,Xia, Wujiong,Yang, Chao
, p. 150 - 151 (2008)
The results of absolute asymmetric photochemical studies on 5- and 7-membered spiroketones in the solid state are described. Photolysis of 7-membered spiroketone undergoing a Norrish type II cyclisation reaction gives enantioselectivity excesses up to 93%. Irradiation of 5-membered spiroketone afforded a racemic product. The results are rationalised by the X-ray crystallographic method.
Covalent Linkage of an R-ω-Transaminase to a d-Amino Acid Oxidase through Protein Splicing to Enhance Enzymatic Catalysis of Transamination
Du, Kun,Li, Rong,Zhang, Dongrui,Feng, Wei
, p. 701 - 709 (2019)
R-ω-Transaminases (RTAs) catalyse the conversion of R-configured amines [e.g., (R)-1-phenylethylamine] into the corresponding ketones (e.g., acetophenone), by transferring an amino group from an amino donor [e.g., (R)-1-phenylethylamine] onto an amino acceptor (e.g., pyruvate), resulting in a co-product (e.g., d-alanine). d-Alanine can be deaminated back to pyruvate by d-amino acid oxidase (DAAOs). Here, through in vivo subunit splicing, the N terminus of an RTA subunit (RTAS) was specifically ligated to the C terminus of a DAAO subunit (DAAOS) through native peptide bonds (RTA&DAAO). RTAS is in close proximity to DAAOS, at a molecular-scale distance. Thus the transfer of pyruvate and d-alanine between RTA and DAAO can be directional and efficient. Pyruvate→d-alanine→pyruvate cycles are efficiently formed, thus promoting the forward transamination reaction. In a different, in vitro noncovalent approach, based on coiled-coil association, the RTAS N terminus was specifically associated with the DAAOS C terminus (RTA#DAAO). In addition, the two mixed individual enzymes (RTA+DAAO) were also studied. RTA&DAAO has a shorter distance between the paired subunits (RTAS–DAAOS) than RTA#DAAO, and the number of the paired subunits is higher than in the case of RTA#DAAO, whereas RTA+DAAO cannot form the paired subunits. RTA&DAAO exhibited a transamination catalysis efficiency higher than that of RTA#DAAO and much higher than that of RTA+DAAO.
Improved synthetic route to methyl 1-fluoroindan-1-carboxylate (FICA Me ester) and 4-methyl derivatives
Koyanagi, Jyunichi,Kamei, Tomoyo,Ishizaki, Miyuki,Nakamura, Hiroshi,Takahashi, Tamiko
, p. 816 - 819 (2014)
An improved synthetic route has been developed for the preparation of methyl 1-fluoroindan-1-carboxylate (FICA Me ester) from 1-indanone. Methyl 4-methyl-1-fluoroindan-1-carboxylate (4-Me-FICA Me ester) was also prepared following the same procedure.
A metal-free method for the facile synthesis of indanonesviathe intramolecular hydroacylation of 2-vinylbenzaldehyde
He, Guoxue,Ma, Jinyu,Zhou, Jianhui,Li, Chunpu,Liu, Hong,Zhou, Yu
supporting information, p. 1036 - 1040 (2021/02/09)
A facile method for the synthesis of indanones was developed under metal- and additive-free conditions, whereinl-proline served as an efficient and environmentally benign catalyst. Compared with previously synthesized indanones, synthesis by the transition-metal-catalyzed intramolecular hydroacylation of 2-vinylbenzaldehyde provided a more green synthetic pathway to indanone scaffolds with good to excellent yields. More importantly, it could be used to synthsize the anti-AD drug donepezil.
Selective Aerobic Oxidation of Secondary C (sp3)-H Bonds with NHPI/CAN Catalytic System
Wang, Lingyao,Zhang, Yuanbin,Yuan, Haoran,Du, Renfeng,Yao, Jia,Li, Haoran
, p. 1663 - 1669 (2020/10/21)
Abstract: The direct aerobic oxidation of secondarty C(sp3)-H bonds was achieved in the presence of N-hydroxyphthalimide (NHPI) and cerium ammonium nitrate (CAN) under mild conditions. Various benzylic methylenes could be oxidized to carbonyl compounds in satisfied selectivity while saturated cyclic alkanes could be further oxidized to the corresponding lactones with the catalytic system. Remarkably, 25% of isochroman was converted to corresponding ketone with a selectivity of 96%. The reaction was initiated by hydrogen atom abstraction from NHPI by cerium and nitrates under oxygen atmosphere to form PINO radicals. 2,2,6,6-Tetramethylpiperidine-1-oxyl (TEMPO) addition experiments showed that the oxidation proceeded via a complex radical chain mechanism and an ion pathway. Graphic Abstract: [Figure not available: see fulltext.]
Rational Construction of an Artificial Binuclear Copper Monooxygenase in a Metal-Organic Framework
Feng, Xuanyu,Song, Yang,Chen, Justin S.,Xu, Ziwan,Dunn, Soren J.,Lin, Wenbin
supporting information, p. 1107 - 1118 (2021/01/25)
Artificial enzymatic systems are extensively studied to mimic the structures and functions of their natural counterparts. However, there remains a significant gap between structural modeling and catalytic activity in these artificial systems. Herein we report a novel strategy for the construction of an artificial binuclear copper monooxygenase starting from a Ti metal-organic framework (MOF). The deprotonation of the hydroxide groups on the secondary building units (SBUs) of MIL-125(Ti) (MIL = Matériaux de l'Institut Lavoisier) allows for the metalation of the SBUs with closely spaced CuI pairs, which are oxidized by molecular O2 to afford the CuII2(μ2-OH)2 cofactor in the MOF-based artificial binuclear monooxygenase Ti8-Cu2. An artificial mononuclear Cu monooxygenase Ti8-Cu1 was also prepared for comparison. The MOF-based monooxygenases were characterized by a combination of thermogravimetric analysis, inductively coupled plasma-mass spectrometry, X-ray absorption spectroscopy, Fourier-transform infrared spectroscopy, and UV-vis spectroscopy. In the presence of coreductants, Ti8-Cu2 exhibited outstanding catalytic activity toward a wide range of monooxygenation processes, including epoxidation, hydroxylation, Baeyer-Villiger oxidation, and sulfoxidation, with turnover numbers of up to 3450. Ti8-Cu2 showed a turnover frequency at least 17 times higher than that of Ti8-Cu1. Density functional theory calculations revealed O2 activation as the rate-limiting step in the monooxygenation processes. Computational studies further showed that the Cu2 sites in Ti8-Cu2 cooperatively stabilized the Cu-O2 adduct for O-O bond cleavage with 6.6 kcal/mol smaller free energy increase than that of the mononuclear Cu sites in Ti8-Cu1, accounting for the significantly higher catalytic activity of Ti8-Cu2 over Ti8-Cu1.
Catalytic Aerobic Oxidation of Alkenes with Ferric Boroperoxo Porphyrin Complex; Reduction of Oxygen by Iron Porphyrin
Kimura, Kento,Kurahashi, Takuya,Matsubara, Seijiro,Murano, Shunpei
supporting information, p. 2493 - 2497 (2021/12/29)
We herein describe the development of a mild and selective catalytic aerobic oxidation process of olefins. This catalytic aerobic oxidation reaction was designed based on experimental and spectroscopic evidence assessing the reduction of atmospheric oxygen using a ferric porphyrin complex and pinacolborane to form a ferric boroperoxo porphyrin complex as an oxidizing species. The ferric boroperoxo porphyrin complex can be utilized as an in-situ generated intermediate in the catalytic aerobic oxidation of alkenes under ambient conditions to form oxidation products that differ from those obtained using previously reported ferric porphyrin catalysis. Moreover, the mild reaction conditions allow chemoselective oxidation to be achieved.
Organotellurium-catalyzed oxidative deoximation reactions using visible-light as the precise driving energy
Deng, Xin,Qian, Rongrong,Zhou, Hongwei,Yu, Lei
supporting information, p. 1029 - 1032 (2020/10/23)
Irradiated by visible light, the recyclable (PhTe)2-catalyzed oxidative deoximation reaction could occur under mild conditions. In comparison with the thermo reaction, the method employed reduced catalyst loading (1 mol% vs. 2.5 mol%), but afforded elevated product yields with expanded substrate scope. This work demonstrated that for the organotellurium-catalyzed reactions, visible light might be an even more precise driving energy than heating because it could break the Te–Te bond accurately to generate the active free radical catalytic intermediates without damaging the fragile substituents (e.g., heterocycles) of substrates. The use of O2 instead of explosive H2O2 as oxidant affords safer reaction conditions from the large-scale application viewpoint.
Engineering the large pocket of an (S)-selective transaminase for asymmetric synthesis of (S)-1-amino-1-phenylpropane
Liu, He,Wang, Hualei,Wei, Dongzhi,Xie, Youyu,Xu, Feng,Xu, Xiangyang,Yang, Lin
, p. 2461 - 2470 (2021/04/22)
Amine transaminases offer an environmentally benign chiral amine asymmetric synthesis route. However, their catalytic efficiency towards bulky chiral amine asymmetric synthesis is limited by the natural geometric structure of the small pocket, representing a great challenge for industrial applications. Here, we rationally engineered the large binding pocket of an (S)-selective ?-transaminase BPTA fromParaburkholderia phymatumto relieve the inherent restriction caused by the small pocket and efficiently transform the prochiral aryl alkyl ketone 1-propiophenone with a small substituent larger than the methyl group. Based on combined molecular docking and dynamic simulation analyses, we identified a non-classical substrate conformation, located in the active site with steric hindrance and undesired interactions, to be responsible for the low catalytic efficiency. By relieving the steric barrier with W82A, we improved the specific activity by 14-times compared to WT. A p-p stacking interaction was then introduced by M78F and I284F to strengthen the binding affinity with a large binding pocket to balance the undesired interactions generated by F44. T440Q further enhanced the substrate affinity by providing a more hydrophobic and flexible environment close to the active site entry. Finally, we constructed a quadruple variant M78F/W82A/I284F/T440Q to generate the most productive substrate conformation. The 1-propiophenone catalytic efficiency of the mutant was enhanced by more than 470-times in terms ofkcat/KM, and the conversion increased from 1.3 to 94.4% compared with that of WT, without any stereoselectivity loss (ee > 99.9%). Meanwhile, the obtained mutant also showed significant activity improvements towards various aryl alkyl ketones with a small substituent larger than the methyl group ranging between 104- and 230-fold, demonstrating great potential for the efficient synthesis of enantiopure aryl alkyl amines with steric hindrance in the small binding pocket.
