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Journal ArticleDOI

A safe production method for acetone cyanohydrin

11 Aug 2010-Tetrahedron Letters (Pergamon)-Vol. 51, Iss: 32, pp 4189-4191
TL;DR: In this article, an easily amenable method was presented to produce acetone cyanohydrin on mole scale (output 39 g/h), using a continuous flow system to overcome the high risks associated with the large-scale use of hydrogen cyanide.
About: This article is published in Tetrahedron Letters.The article was published on 2010-08-11. It has received 28 citations till now. The article focuses on the topics: Acetone cyanohydrin & Cyanide.
Citations
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Journal ArticleDOI
TL;DR: This Review discusses recent literature examples of continuous-flow organic synthesis where hazardous reactions or extreme process windows have been employed, with a focus on applications of relevance to the preparation of pharmaceuticals.
Abstract: In the past few years, continuous-flow reactors with channel dimensions in the micro- or millimeter region have found widespread application in organic synthesis. The characteristic properties of these reactors are their exceptionally fast heat and mass transfer. In microstructured devices of this type, virtually instantaneous mixing can be achieved for all but the fastest reactions. Similarly, the accumulation of heat, formation of hot spots, and dangers of thermal runaways can be prevented. As a result of the small reactor volumes, the overall safety of the process is significantly improved, even when harsh reaction conditions are used. Thus, microreactor technology offers a unique way to perform ultrafast, exothermic reactions, and allows the execution of reactions which proceed via highly unstable or even explosive intermediates. This Review discusses recent literature examples of continuous-flow organic synthesis where hazardous reactions or extreme process windows have been employed, with a focus on applications of relevance to the preparation of pharmaceuticals.

1,059 citations

Journal ArticleDOI
TL;DR: This review covers some of the latest and most relevant developments in the field of continuous flow chemistry with the focus on hazardous reactions.
Abstract: Over the last two decades, flow technologies have become increasingly popular in the field of organic chemistry, offering solutions for engineering and/or chemical problems. Flow reactors enhance the mass and heat transfer, resulting in rapid reaction mixing, and enable a precise control over the reaction parameters, increasing the overall process selectivity, efficiency and safety. These features allow chemists to tackle unexploited challenges in their work, with the ultimate objective making chemistry more accessible for laboratory and industrial applications, avoiding the need to store and handle toxic, reactive and explosive reagents. This review covers some of the latest and most relevant developments in the field of continuous flow chemistry with the focus on hazardous reactions.

490 citations

Journal ArticleDOI
TL;DR: This review describes the fundamentals and latest developments in multiphase microfluidics for producing biocompatible materials that are precisely controlled in size, shape, internal morphology and composition and describes some micro fluidic applications that synthesize drug molecules, handle biological substances and biological units, and imitate biological organs.

262 citations


Cites background from "A safe production method for aceton..."

  • ...Microfluidic reaction devices can be used to generate products in higher yield, purity and selectivity when compared to batch reactors, while a disadvantage of themicrofluidic reaction technology is the fact that only small quantities of product can be prepared [373]....

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Journal ArticleDOI
TL;DR: The Mikroreaktortechnologie einzigartige Moglichkeit, ultraschnelle exotherme Reaktionen durchzufuhren, and erlaubt die Realisierung von Reaktionsbedingungen, die uber sehr instabile oder sogar explosive Zwischenprodukte ablaufen, erreicht werden as mentioned in this paper.
Abstract: In den letzten Jahren haben Durchflussreaktoren mit Kanalabmessungen im Mikrometer- oder Millimeterbereich weitverbreitete Anwendung in der organischen Synthese gefunden. Diese Reaktoren sind durch ihre ausergewohnlich schnellen Warme- und Stoffubertragung gekennzeichnet. Auser bei den schnellsten Reaktionen kann in mikrostrukturierten Bauelementen dieses Typs eine fast augenblickliche Vermischung der Reaktanten erreicht werden. Ebenso lassen sich Probleme wie Warmestau, Uberhitzungszonen (Hot-Spots) und thermisches Durchgehen vermeiden. Aufgrund der kleinen Reaktorvolumina ist die Prozesssicherheit erheblich verbessert, selbst wenn harsche Reaktionsbedingungen angewendet werden. Somit bietet die Mikroreaktortechnologie eine einzigartige Moglichkeit, ultraschnelle exotherme Reaktionen durchzufuhren, und erlaubt die Realisierung von Reaktionen, die uber sehr instabile oder sogar explosive Zwischenprodukte ablaufen. Dieser Aufsatz behandelt aktuelle Literaturbeispiele fur die organische Synthese unter kontinuierlichem Durchfluss, in denen eine gefahrliche Chemie oder extreme Prozessfenster angewendet wurden, wobei der Schwerpunkt vor allem auf Anwendungen liegt, die fur die Herstellung von Pharmazeutika von Bedeutung sind.

166 citations

Journal ArticleDOI
TL;DR: In this article, the effects of the capillary length (0.4-2.2 m), flow rate ( 0.1-12 mL/min), and aqueous-to-organic volumetric flow ratio (0.,25-9) on the slug, bubbly, parallel, and annular flow hydrodynamics were investigated.
Abstract: The capillary microreactor, with four stable operating flow patterns and a throughput range from grams per hour to kilograms per hour, presents an attractive alternative to chip-based and microstructured reactors for laboratory- and pilot-scale applications. In this article, results for the extraction of 2-butanol from toluene under different flow patterns in a water/toluene flow in long capillary microreactors are presented. The effects of the capillary length (0.4–2.2 m), flow rate (0.1–12 mL/min), and aqueous-to-organic volumetric flow ratio (0.25–9) on the slug, bubbly, parallel, and annular flow hydrodynamics were investigated. Weber-number-dependent flow maps were composed for capillary lengths of 0.4 and 2 m that were used to interpret the flow pattern formation in terms of surface tension and inertia forces. When the capillary length was decreased from 2 to 0.4 m, a transition from annular to parallel flow was observed. The capillary length had little influence on slug and bubbly flows. The flow p...

134 citations

References
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Journal ArticleDOI
TL;DR: Microreview as mentioned in this paper focuses on recent developments made in the field of micro reaction technology, highlighting the advantages associated with its use through the synthesis of a diverse array of molecules and highlights the potential of a compound, however, depends not only on structural complexity, but also on the ability to prepare the compound via a scalable synthetic pathway.

287 citations

Journal ArticleDOI
TL;DR: This work presents the development of an unprecedented catalytic asymmetric Diels–Alder reaction of 3-vinylindoles 1 with different representative dienophiles 2 (Scheme 1).
Abstract: Diels–Alder type reactions are amongst the most useful transformations in organic chemistry for the construction of cyclohexene structures, often containing multiple stereocenters. Catalytic asymmetric variants of these [4+2] cycloadditions have been reported for different diene–dienophile combinations, showing in several instances outstanding synthetic utility. Herein, we present the development of an unprecedented catalytic asymmetric Diels–Alder reaction of 3-vinylindoles 1 with different representative dienophiles 2 (Scheme 1). Our studies were motivated by the stunning

199 citations

Journal ArticleDOI
Eun Ju Park1, Seungeon Lee1, Sukbok Chang1
TL;DR: It was found that the addition of trimethylsilyl cyanide (TMSCN) significantly accelerates the conversion presumably by delivering free cyanide ion in situ, thus producing various types of alpha-aryl cyanoacetates in high yields under mild conditions.
Abstract: A procedure for the Cu-catalyzed hydrocyanation of alpha-aryl diazoesters has been developed using acetone cyanohydrin as a source of hydrogen cyanide (HCN). It was found that the addition of trimethylsilyl cyanide (TMSCN) significantly accelerates the conversion presumably by delivering free cyanide ion in situ, thus producing various types of alpha-aryl cyanoacetates in high yields under mild conditions.

49 citations

Book ChapterDOI
01 Jan 2010
TL;DR: An overview of the reported examples in which the microreactor technology and the multicomponent approach are combined, usually with dramatically improved results compared to those previously reported can be found in this paper.
Abstract: Multicomponent reactions are an important tool in organic synthesis as they often allow the circumvention of multistep procedures by combining three or more molecules into one structure in a single step. An additional asset of the approach is the significant increase of the combinatorial possibilities, since a modification of the final product is easily accomplished by implementing minor changes in the reaction setup; this obviously allows considerable savings in time and resources. These advantages are of particular interest in pharmaceutical research for the construction of libraries. In order to increase the sustainability of chemical processes, the field is intensively explored, and novel reactions are frequently reported. Microreactor technology also offers a contemporary way of conducting chemical reactions in a more sustainable fashion due to the miniaturization and increased safety, and also in a technically improved manner due to intensified process efficiency. This relatively new technology is implemented in novel and improved applications and is getting more and more used in chemical research. The combination of the benefits from the two approaches clearly presents an attractive reaction design, and this chapter presents an overview of the reported examples in which the microreactor technology and the multicomponent approach are combined, usually with dramatically improved results compared to those previously reported.

42 citations

Journal ArticleDOI
TL;DR: Thirty two analogues of phencyclidine were synthesised and tested as inhibitors of trypanothione reductase (TryR), a potential drug target in trypanosome and leishmania parasites, and analogues with improved enzymatic and biological activity were obtained.
Abstract: Thirty two analogues of phencyclidine were synthesised and tested as inhibitors of trypanothione reductase (TryR), a potential drug target in trypanosome and leishmania parasites. The lead compound BTCP (1, 1-(1-benzo[b]thiophen-2-yl-cyclohexyl) piperidine) was found to be a competitive inhibitor of the enzyme (Ki=1 μm) and biologically active against bloodstream T. brucei (EC50=10 μm), but with poor selectivity against mammalian MRC5 cells (EC50=29 μm). Analogues with improved enzymatic and biological activity were obtained. The structure–activity relationships of this novel series are discussed.

41 citations