- Batch kinetics in flow: Online IR analysis and continuous control
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Currently, kinetic data is either collected under steady-state conditions in flow or by generating time-series data in batch. Batch experiments are generally considered to be more suitable for the generation of kinetic data because of the ability to collect data from many time points in a single experiment. Now, a method that rapidly generates time-series reaction data from flow reactors by continuously manipulating the flow rate and reaction temperature has been developed. This approach makes use of inline IR analysis and an automated microreactor system, which allowed for rapid and tight control of the operating conditions. The conversion/residence time profiles at several temperatures were used to fit parameters to a kinetic model. This method requires significantly less time and a smaller amount of starting material compared to one-at-a-time flow experiments, and thus allows for the rapid generation of kinetic data. Go with the flow: By continuously manipulating the flow rate and temperature, classical batch-reactor time-series data were obtained with microreactors under conditions of low dispersion with inline IR analysis. The approach requires significantly less time and a smaller amount of starting material compared to one-at-a-time flow experiments, which allows for the rapid generation of kinetic data.
- Moore, Jason S.,Jensen, Klavs F.
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- Greener Paal-Knorr Pyrrole Synthesis by Mechanical Activation
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A straightforward and solventless synthesis of pyrroles was developed by using mechanochemical activation and a biosourced organic acid as the catalyst. Relative to traditional Paal-Knorr methodologies, various N-substituted pyrroles were obtained in very short reaction times. By reaction with unreactive diketones, desymmetrized aliphatic and aromatic compounds were also synthesized.
- Akelis, Liudvikas,Rousseau, Jolanta,Juskenas, Robertas,Dodonova, Jelena,Rousseau, Cyril,Menuel, Stphane,Prevost, Dominique,Tumkeviius, Sigitas,Monflier, Eric,Hapiot, Frdric
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- Multijet oscillating disc millireactor: A novel approach for continuous flow organic synthesis
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This report discloses proof of concept and experimental results from a project involving design, development, and investigation of a novel approach for flow chemistry and the realization of equipment operating according to this new approach. This device is named multijet oscillating disk (MJOD) reactor and is dedicated to continuous flow organic synthesis in milliscale. Characteristics such as the importance of the multijet disk unit, with or without oscillating, and possible limitations, such as back-mixing, have been explored, and the flow system is benchmarked with other technologies. Several well-known reactions and syntheses usefully both in the chemical industry as well as in the research laboratory have been conducted using the new system, which have been benchmarked with batch- and microreactor protocols. In particular the Haloform reaction, the Nef reaction, nucleophilic aromatic substitution, the Paal-Knorr pyrrole synthesis, sodium borohydride reduction, O-allylation, the Suzuki cross-coupling reaction, the Hofmann rearrangement and N-acylation were performed during the study of the MJOD reactor performance. Our investigations revealed that the MJOD millireactor system can produce various organic compounds at a high rate concomitant with an excellent selectivity. A Hofmann rearrangement was conducted, a reaction that involves handling of a slurry of the substrate. This reaction was successfully conducted, achieving a quantitative conversion into the target molecule.
- Liguori, Lucia,Bjorsvik, Hans-Rene
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experimental part
p. 997 - 1009
(2011/12/21)
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- Photosensitized oxidations of substituted pyrroles: Unanticipated radical-derived oxygenated products
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(Chemical Equation Presented) Photooxidation of pyrrole adducts 7-10 has been investigated in order to establish a general reaction pattern andmechanism for the formation of the resulting oxygenated products. The reactions were performed in several solvents utilizing both type I and type II sensitizers. In most cases, photooxidations gave complex mixture of products. Among these products, 5,5- or 6,5-bicyclic lactams (11, 15, and 19), maleimide 12 unsaturated γ-lactams (16 and 20), 5-hydroxylactams (13, 17, and21), and 5-methoxylactams (14, 18, and22) wereisolated and characterized. Photooxidation of 2,5-dimethyl-substituted pyrrole 10 in aprotic solvents unexpectedly afforded aldehyde 23 as the major product. Moreover, photooxidation of pyrrole adduct 10 in protic solvents exclusively gave the unprecedented solvent-trapped products 24-27. The formation of products 11-22 was rationalized by the intermediacy of a commonendoperoxide intermediate, whichcould be formedby both type I and type II mechanisms. Compounds 23-27 were most probably formed via an electron-transfer mechanism. 2009 American Chemical Society.
- Alberti, Mariza N.,Vougioukalakis, Georgios C.,Orfanopoulos, Michael
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supporting information; experimental part
p. 7274 - 7282
(2010/01/16)
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- Novel innovation systems for a cellular approach to continuous process chemistry from discovery to market
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Continuous processing of liquid/liquid synthesis and microreaction technology are shown to reduce the cost of process development and manufacturing of active pharmaceutical ingredients and other functional molecules on a commercial scale. Combinatorial synthesis systems for continuous chemistry are introduced, and their applications are described. Reactions within these systems scale seamlessly in standardized commercial continuous synthesis equipment allowing rapid access to kilogram quantities of advanced intermediates. Chemical and process development within such systems are illustrated by a case study of a continuous multistep process. Additionally, another case study shows the benefit of microreaction technology in the manufacture of high value added functional chemicals.
- Schwalbe, Thomas,Autze, Volker,Hohmann, Michael,Stirner, Wolfgang
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p. 440 - 454
(2013/09/05)
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- Novel heterocyclic compounds having hypolipidemic, hypocholesteremic activities process for their preparation and pharmaceutical compositions containing them and their use in medicine
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Novel β-aryl-α-substituted propanoic acids having hypolipidemic and hypocholesteremic activities.
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- Novel heterocyclic compounds, their preparation, pharmaceutical compositions containing them and their use in medicine
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The present invention relates to novel substituted pyrrole compounds, their derivatives, their analogs, their tautomeric forms, their stereoisomers, their polymorphs, their pharmaceutically acceptable salts, their pharmaceutically acceptable solvates and
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- Method for preparing amlodipine
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Amlodipine is prepared in a high yield by subjecting a pyrrole derivative, methyl aminocrotonate and 2-chlorobenzaldehyde to a Hantzsch reaction, and converting the pyrrole residue of the resulting 1,4-dihydropyridine derivative to an amine group by the action of hydroxylamine hydrochloride.
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- Microreaction technology as a novel approach to drug design, process development and reliability
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This paper focuses on the application of microreaction technology in the life science industry. Certain features of microreaction technology, for example, mixing, heat transfer, and residence time distribution, are discussed. Important advantages such as high operational safety and the possibility to transfer the experimental results directly from laboratory to the production of pilot-plant scales are mentioned. Potential application fields in the drug discovery and development processes, from research to production, by including chemical synthesis of different targets in the case of the quinoline acid derivative (ciprofloxacin) and the Paal - Knorr pyrrole synthesis are presented.
- Taghavi-Moghadam, Shahriyar,Kleemann, Axel,Golbig, Klaus Georg
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p. 652 - 658
(2013/09/07)
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- Synthesis and Stereoselective Reactions of 2-(Pyrrol-1-yl)alkanals and 2-(pyrrol-1-yl)alkan-1-ones
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2-(2,5-Dimethylpyrrol-1-yl)alkanals, 2-(pyrrol-1-yl)alkanals, and 2-(2,5-dimethylpyrrol-1-yl)alkan-1-ones were prepared.The reactions of these compounds with Grignard and hydride reagents proceeded stereoselectively to give the corresponding 2-(pyrrol-1-yl)alcohols, which were converted into 2-aminoalcohols, such as norephedrine and ephedrine, by cleavage of the pyrrole ring.
- Kashima, Choji,Maruyama, Tatsuya,Fujioka, Yoko,Harada, Kazuo
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p. 1041 - 1046
(2007/10/02)
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