Chemical reactions in supercritical carbon dioxide: from laboratory to commercial plantThis work was presented at the Green Solvents for Catalysis Meeting held in Bruchsal, Germany, 13–16th October 2002.

Licence, Peter; Ke, Jie; Sokolova, Maia; Ross, Stephen K.; Poliakoff, Martyn

doi:10.1039/b212220k

Cited by 225 publications

(86 citation statements)

References 22 publications

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“…1 H and 13 C NMR spectra were measured on a Bruker Avance 3 spectrometer (Bruker BioSpin, Billerica, MA, USA) (200 MHz for proton) with samples dissolved in CDCl 3 . Chemical shifts are presented in ppm using tetramethylsilane (TMS) as reference.…”

Section: Methodsmentioning

confidence: 99%

Proline derivatives as organocatalysts for the aldol reaction in conventional and non-conventional reaction media

Cassaro

Oliveira

Gariani

et al. 2013

Green Processing and Synthesis

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Different l -proline derivatives were investigated as organocatalysts for the aldol condensation reaction between acetone and 4-nitrobenzaldehyde, in a conventional organic solvent (DMSO), in supercritical carbon dioxide, and in mixtures of this solvent and 1-allyl-3-alkyllimidazolium chlorides ionic liquids. The catalysts evaluated were:and (2S,3R,4R,5S,6R)-6-(acetoxymethyl)-3-[(S)-pyrrolidine-2-carboxamido]-tetrahydro-2H-pyran-2,4,5-triyl triacetate (peracetylated glucosamine-l -proline). One of the catalysts tested, the tert-butyldimethylsilyloxy-l -proline, was very effective, allowing lower reaction times, resulting in better yields and enantiomeric excesses than l -proline itself, both in organic solvent (DMSO) and in sc-CO 2 or a mixture of sc-CO 2 and ionic liquids. The use of the ionic liquid resulted in better yields and enantiomeric excesses in sc-CO 2 . The other catalysts tested were not as effective, resulting in yields and enantiomeric excesses similar or inferior to the ones obtained with l -proline.

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Section: Methodsmentioning

confidence: 99%

Proline derivatives as organocatalysts for the aldol reaction in conventional and non-conventional reaction media

Cassaro

Oliveira

Gariani

et al. 2013

Green Processing and Synthesis

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“…The absence of interphase mass transport effects means that hydrogenation can be be performed efficently in a continuous flow system. [16] High throughput and increased safety due to a smaller reactor volume make continuous flow technology an attractive alternative to batch processing. A schematic of our flow apparatus is shown in Figure 1.…”

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confidence: 99%

Continuous Flow Hydrogenation of a Pharmaceutical Intermediate, [4‐(3,4‐Dichlorophenyl)‐3,4‐dihydro‐2H‐naphthalenyidene]methylamine, in Supercritical Carbon Dioxide

2007

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Abstract:The hydrogenation of complex pharmaceutical intermediate, rac-sertraline imine has been optimized as a continuous flow process utilizing a palladium/calcium carbonate (Pd/CaCO 3 ) catalyst and hydrogen in supercritical carbon dioxide (scCO 2 ). Superior levels of selectivity were obtained in the flow system possibly attributable to the heat transfer properties of scCO 2 which help to remove excess heat from the catalyst surface.Keywords: carbon dioxide; diastereoselectivity; hydrogenation; sertraline; supercritical fluidsThe excessive use of organic solvents in synthesis, purification and cleaning is the largest single contributor to overall chemical waste in the pharmaceutical industry. Therefore, a new technology that minimizes the use of organic solvents will help make pharmaceutical and fine chemical synthesis more sustainable. Supercritical fluids (SCFs) and, in particular, supercritical CO 2 (scCO 2 ), have emerged as alternative green solvents which can help the pharmaceutical industry attain this goal. [1,2] For instance, SCF chromatography [3,4] and SCF extraction [5,6] have proved to be powerful tools for the separation of active pharmaceutical ingredients (APIs) from complex mixtures. scCO 2 has also more recently been applied to anti-solvent precipitation of drug particles from solution.[7-10] scCO 2 is highly suitable for pharmaceutical processing because it is non-toxic and has relatively mild critical parameters (T c = 31 8C, P c = 74 bar) so that the advantages of near-critical and scCO 2 can be achieved, whilst operating at relatively low temperatures where degradation of sensitive molecules is unlikely.The application of scCO 2 as a solvent for the synthesis of pharmaceuticals has not yet been fully realized. This is because synthetic research in scCO 2 has focused largely on model substrates and compounds relevent to the bulk and fine chemicals industry. [11][12][13] This article explores the use of scCO 2 as a solvent for the hydrogenation of a complex pharmaceutical intermediate, [4-(3,4-dichlorophenyl)-3,4-dihydro-2H-naphthalenyidene]methylamine, also known as racsertraline imine 1.(4S)-Sertraline imine 1a is an intermediate in the synthesis of cis-(1S,4S)-sertraline hydrochloride 2, marketed under the name, Zoloft (Scheme 1), a multi-billion dollar drug developed originally by Pfizer for the treatment of depression and other anxiety related disorders. [14,15] Today Zoloft is manufactured in relatively few steps by first reacting 1-naphthol, 3, and 1,2-dichlorobenzene, 4, with aluminium chloride to provide the racemic intermediate ketone. Simulated moving bed (SMB) chromatography is then used to separate efficiently the (4S)-and (4R)-enantiomers. Enantiomerically pure (4S)-ketone is then reacted with methylamine to afford the imine 1a. Diastereoselective hydrogenation puts in the second chiral centre to afford (4S)-sertraline before conversion to the hydrochloride salt 2 (Scheme 1).We chose to study the hydrogenation of imine 1a in scCO 2 for a number of reasons. It has both regio-a...

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“…It has been used in dry cleaning, replacing the bioaccumulating chemical perchloroethylene, and in paint spraying applications (83,84). Continuous hydrogenation (85), Friedel-Crafts acylation (86), and hydroformylation (66) processes based on CO 2 were developed at the University of Nottingham and, in collaboration with Thomas Swan & Co., have led to the construction of a demonstration plant (87).…”

Section: Alternative Solventsmentioning

confidence: 99%

Green chemistry: the emergence of a transformative framework

Anastas

Beach

2007

Green Chemistry Letters and Reviews

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Since the Twelve Principles of Green Chemistry were formulated in the 1990s, there have been tremendous successes in developing new products and processes to be more compatible with human health, the environment, and sustainability goals. This review gives a sampling of research successes from the last 20 years, including advances in synthetic efficiency, application of alternative synthetic methods, use of less hazardous solvents and reagents, and development of renewable resources for chemical feedstocks. The future of green chemistry will depend on innovations that consolidate and integrate these achievements that have been made, using all Twelve Principles as a framework for intentional design. Designing for sustainability and reduced hazard should not be viewed as constraining, but rather as providing the freedom to explore and invent, bridging continents and scientific disciplines to create new solutions.

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Chemical reactions in supercritical carbon dioxide: from laboratory to commercial plantThis work was presented at the Green Solvents for Catalysis Meeting held in Bruchsal, Germany, 13–16th October 2002.

Cited by 225 publications

References 22 publications

Proline derivatives as organocatalysts for the aldol reaction in conventional and non-conventional reaction media

Proline derivatives as organocatalysts for the aldol reaction in conventional and non-conventional reaction media

Continuous Flow Hydrogenation of a Pharmaceutical Intermediate, [4‐(3,4‐Dichlorophenyl)‐3,4‐dihydro‐2H‐naphthalenyidene]methylamine, in Supercritical Carbon Dioxide

Green chemistry: the emergence of a transformative framework

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