1077-79-8Relevant academic research and scientific papers
Teflon AF-2400 mediated gas-liquid contact in continuous flow methoxycarbonylations and in-line FTIR measurement of CO concentration
Koos, Peter,Gross, Ulrike,Polyzos, Anastasios,O'Brien, Matthew,Baxendale, Ian,Ley, Steven V.
, p. 6903 - 6908 (2011)
We report on the development of a continuous flow process for the palladium catalysed methoxycarbonylation of aryl, heteroaromatic and vinyl iodides and an aryl bromide using a Teflon AF-2400 based Tube-in-Tube reactor to mediate the selective permeation of carbon monoxide into solution at elevated pressures. The low volume of pressurised gas within the reactor (5.6 mL) offers the potential for an enhanced safety profile compared to batch processes. We also present preliminary results for the use of in situ FTIR to measure solution concentrations of carbon monoxide and demonstrate the use of a second reactor to effect the removal of carbon monoxide from the flow stream.
Microbial asymmetric syntheses of 3-alkylphthalide derivatives
Kitayama, Takashi
, p. 3765 - 3774 (1997)
Phthalide derivatives, almost all of which have an S-configuration, have a wide range of activity and exist in Angerica sinensis Diels and Sligusticum wallichiii Franch. For the first time, optically active (S)-3-methylphthalide derivatives were synthesized using two methods, asymmetric microbial reduction and microbial hydroxylation. For the first method, methyl 2-acetylbenzoate was synthesized as a substrate, which was reduced asymmetrically by Geotrichum candidum IFO 34614 to obtain (S)-3-methylphtalide in 92% yield (99% enantiomeric excess, ee). For the second method, 2-ethylbenzoic acid was employed as a substrate which was hydroxylated asymmetrically at the benzylic position by either Pseudomonas putida ATCC 12633 or Aspergillus niger IFO 6661, whose fermentation was induced by o-toluic acid, to obtain (S)-3-methylphthalide in 80% yield (99% ee). (S)-3-Butylphthalide and (S)-3-octylphthalide were obtained in the same manner in 12% yield (ee = 99%) and 10% yield (ee = 99%), respectively.
Oxidative Cleavage of Substituted Naphthalenes Induced by Irradiated Semiconductor Powders
Fox, Marye Anne,Chen, Chia-Chung,Younathan, Janet N. N.
, p. 1969 - 1974 (1984)
Electron-rich members of a series of substituted naphthalenes react with oxygen to give ring-cleaved products upon long wave ultraviolet irradiation of TiO2 powders suspended in oxygen-saturated acetonitrile solutions of the arene.Reactivity within the series parallels trends in the oxidation potential, i.e., the species with the less positive oxidation potential appears to react more efficiently.A mechanism involving sensitized formation of the substituted naphthalene cation radical is suggested for the semiconductor-mediated photocatalysis.
Direct Synthesis of Chiral NH Lactams via Ru-Catalyzed Asymmetric Reductive Amination/Cyclization Cascade of Keto Acids/Esters
Shi, Yongjie,Tan, Xuefeng,Gao, Shuang,Zhang, Yao,Wang, Jingxin,Zhang, Xumu,Yin, Qin
supporting information, p. 2707 - 2713 (2020/03/30)
Lactams with a stereogenic center adjacent to the N atom have existed in many medicinal agents and bioactive alkaloids. Herein we report a broadly applicable synthesis of enantioenriched NH lactams through a one-pot asymmetric reductive amination/cyclization sequence of easily available keto acids/esters. Such cascade processes alleviate the demand for protecting group manipulations as well as intermediate purification. This strategy is capable of constructing enantioenriched lactams and benzo-lactams of a five-, six-, or seven-membered ring in generally high yield and with excellent enantioselectivities (up to 97% ee). Scalable and concise syntheses of key drug intermediates have further displayed the importance of this methodology.
Capturing Intermediates in the Reaction Catalyzed by NosN, a Class C Radical S-Adenosylmethionine Methylase Involved in the Biosynthesis of the Nosiheptide Side-Ring System
Wang, Bo,Lamattina, Joseph W.,Marshall, Savannah L.,Booker, Squire J.
supporting information, (2019/04/17)
Nosiheptide is a ribosomally synthesized and post-translationally modified thiopeptide natural product that possesses antibacterial, anticancer, and immunosuppressive properties. It contains a bicyclic structure composed of a large macrocycle and a unique
Capturing Intermediates in the Reaction Catalyzed by NosN, a Class C Radical S-Adenosylmethionine Methylase Involved in the Biosynthesis of the Nosiheptide Side-Ring System
Wang, Bo,Lamattina, Joseph W.,Marshall, Savannah L.,Booker, Squire J.
supporting information, p. 5788 - 5797 (2019/04/17)
Nosiheptide is a ribosomally synthesized and post-translationally modified thiopeptide natural product that possesses antibacterial, anticancer, and immunosuppressive properties. It contains a bicyclic structure composed of a large macrocycle and a unique
Ruthenium-Catalyzed Enantioselective Hydrogenation/Lactonization of 2-Acylarylcarboxylates: Direct Access to Chiral 3-Substituted Phthalides
Lu, Bin,Zhao, Mengmeng,Ding, Guangni,Xie, Xiaomin,Jiang, Lili,Ratovelomanana-Vidal, Virginie,Zhang, Zhaoguo
, p. 3989 - 3996 (2017/09/13)
Highly enantioselective tandem hydrogenation/lactonization of various 2-acylarylcarboxylates including 2-aroylarylcarboxylates were realized by using [RuCl(benzene)(S)-SunPhos]Cl as the catalyst under mild reaction conditions. Excellent enantioselectivities (up to 99.6 % ee) and activities (S/C=1000) were obtained. This convenient and practical method enables a direct access to a series of highly optically pure 3-substituted phthalides that are very important molecules as valuable pharmacological compounds and diversified synthons for medicinal chemistry. Moreover, a gram-scale reaction was performed to further demonstrate the practicality of this approach.
Synthesis of (R)-3-methylphthalide by reductive cyclization of a 2-acylarylcarboxylate using the chiral boronic ester TarB-H and sodium borohydride
De Souza, Aline Aparecida Nunes,Taylor, Jason Guy
, p. 657 - 660 (2017/01/16)
Background: Phthalides are pervasive benzolactone structural frameworks in nature and have a broad profile of biological activities. Catalytic asymmetric reduction with the in situ lactonization of 2-acylarylcarboxylate compounds is an efficient strategy for chiral phthalide synthesis. The tartaric acid-derived reagent TarB-X is capable of mediating the asymmetric reduction of aromatic ketones using either LiBH4 or NaBH4 as the reductant. Up until now, the asymmetric reduction by Tarb- H/NaBH4 had not been applied to the synthesis of chiral phthalides. Methods: The requsite substrate, methyl 2-acetylbenzoate was obtained by a two step reaction starting from phthalic anhydride and maloninc acid. Tarb-H was obtained by treatment of L-(+)-tartaric acid with phenylboronic acid. The catalyst and NaBH4 were reacted with methyl 2-acetylbenzoate at room temperature for 1 h. The structure of (R)-3-Methylphthalide was established by NMR and mass spectrometry and its enantiomeric excess was determined by HPLC. The relative configuration was deduced by comparison of the optical rotation with data given in the literature. Results: (R)-3-Methylphthalide was obtained in moderte yield and high enantiomeric excess. Conclusion: (R)-3-methylphthalide was prepared in high enantiomeric excesses using an inexpensive and easily synthesized tartaric acid derived boronic ester (TarB-H) with sodium borohydride. The chiral phthalide was obtained in an open flask by reductive cyclization of a 2-acylarylcarboxylate.
A general continuous flow method for palladium catalysed carbonylation reactions using single and multiple tube-in-tube gas-liquid microreactors
Gross, Ulrike,Koos, Peter,O'brien, Matthew,Polyzos, Anastasios,Ley, Steven V.
supporting information, p. 6418 - 6430 (2016/02/18)
A series of continuous flow chemistry processes that facilitate the palladium-catalysed carbonylation of aryl and vinyl iodides and aryl bromides with a range of alkoxy, hydroxy and amino nucleophiles is reported. Harnessing a semipermeable Teflon AF-2400 Tube-in-Tube assembly, these reactors permit the controlled transport of carbon monoxide into solution at elevated pressure to generate homogeneous flow streams, avoiding some potential issues associated with segmented flow gas-liquid reactors. As the volume of pressurised gas contained within the device is low, the hazards associated with this are potentially mitigated relative to comparable batch processes. We also show how the incorporation of a second in-line gas-flow reactor allows for the sequential introduction of two gases (carbon monoxide and a gaseous nucleophile) into the reaction stream. A Teflon AF-2400 Tube-in-Tube reactor facilitates the use of carbon monoxide in continuous-flow C-C bond forming reactions providing esters, amides, carboxylic acids, lactones and lactams. Two reactors can be used in series to permit the sequential addition of two reactive gases (CO and Me2NH) into the flow stream.
NOVEL IMIDAZOPYRIDINE COMPOUND
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Page/Page column 20, (2012/04/23)
For the prevention and/or treatment of chymase-mediated diseases such as skin diseases, circulatory diseases, digestive system diseases, respiratory diseases, liver diseases, ocular diseases or the like, a drug is provided having as an active ingredient a
