Showing papers by "Christian V. Stevens published in 2010"
TL;DR: In this paper, a simple procedure for the conversion of 5-(Hydroxymethyl)furfural to (5-alkyl- and 5-arylaminomethyl-furan-2-yl)methanol has been developed.
80 citations
TL;DR: In this article, a resin-based crystallization method was developed for the recovery of succinic acid (SA) crystals from fermentation broths (FB) using Actinobacillus succinogenes.
57 citations
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
TL;DR: A comparison study of Radical Reactions and Oxidation of Halogenated Alcohols through Synthesis of γ-Halo Ketones and Aldehydes and Nucleophilic Substitution .
Abstract: 2.6. Radical Reactions 5932 2.6.1. Radical Halogenation 5932 2.6.2. Ring-Opening and Expansion 5932 2.6.3. Miscellaneous 5934 2.7. Ring-Opening and Ring Expansion 5934 2.7.1. Cyclic Acetals 5934 2.7.2. Epoxides 5934 2.7.3. Cycloalkanes 5935 2.7.4. Ozonides 5937 2.7.5. Ring Expansion 5938 2.8. Ring Closure and Contraction 5939 2.8.1. Ring Closure 5939 2.8.2. Ring Contraction 5943 2.8.3. Ring Rearrangements 5943 2.9. Oxidation 5943 2.9.1. Oxidation of Halogenated Alcohols 5943 2.9.2. Oxidation of Olefins 5945 2.10. Pericyclic Reactions 5945 2.10.1. Cycloadditions 5945 2.10.2. Sigmatropic Rearrangements 5945 3. Synthesis of γ-Halo Ketones and Aldehydes 5946 3.1. Nucleophilic Substitution 5946 3.1.1. Enolate Alkylation 5946 3.1.2. Conversion of an Alcohol or Ether into an Alkyl Halide 5947
36 citations
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.
28 citations
TL;DR: Trialkyl and silylated dialkyl phosphites were evaluated as phosphorus nucleophiles for the addition to quinolines in a strong acidic medium allowing consecutive 1,4- and 1,2-addition breaking up the aromatic stabilisation, thereby leading to 2, 4-diphosphono-1,2,3,4 -tetrahydroquinoline addition in one single reaction step in moderate to good yields.
28 citations
TL;DR: In this article, the hetero Diels-Alder reactions of 2-nitrosotoluene and some representative acylnitrosodienophiles with a selected set of 1,3-dienes were studied under microflow conditions.
28 citations
TL;DR: In this article, a series of spiro[2-oxoindole-pyrrolidines] was synthesized in a straightforward manner using a Kharasch radical cyclization reaction of trichloroacetylated precursors.
17 citations
TL;DR: This article presents a Kennard-Stone-based algorithm, with a distance measure based on the distance matrix, for the selection of the most diverse set of conformations, successfully applied to macrocyclic alkenes.
Abstract: The properties and functions of (bio)molecules are closely related to their molecular conformations. A variety of methods are available to sample the conformational space at a relatively low level ...
16 citations
TL;DR: This work wanted to investigate possible routes via ring opening of alpha-amino phosphonates with an oxanorbornene skeleton, as these can be synthesized with high stereoselectivity using different Lewis acids, leading to a range of products.
Abstract: Phosphonylated azaheterocycles are an important class of compounds with high biological potential as conformationally restricted bioisosteres of amino acids. Therefore, it is of interest to synthesize conformationally constrained amino phosphonates. We wanted to investigate possible routes via ring opening of α-amino phosphonates with an oxanorbornene skeleton, as these can be synthesized with high stereoselectivity. This was achieved using different Lewis acids, leading to a range of products. The reaction with TiCl4 and FeCl3 was modelled at a DFT level of theory to get insight in the pathways towards the corresponding products. To ease the work up, the Fe(III) catalyst was coated on montmorillonite clay, but this accelerated aromatization after ring opening. Quenching the FeCl3 catalyzed reaction mixture on celite caused complete aromatization.
14 citations
TL;DR: In this article, the synthesis of epibatidine analogues by a straightforward one-pot method was presented, starting from cyclohexanones bearing a leaving group at the 4 position.
01 Jan 2010
TL;DR: In this paper, the synthesis of selected five-membered phosphorus heterocycles containing a stereogenic phosphorus in an optically active form was presented, and their utility in a few asymmetric reactions was also briefly mentioned.
Abstract: This review presents the synthesis of selected five-membered phosphorus heterocycles containing a stereogenic phosphorus in an optically active form Their utility in a few asymmetric reactions is also briefly mentioned
TL;DR: In this paper, a series of benzo-fused tricyclic β-lactams, most of them phosphonobenzocarbachems, were prepared in a straightforward way starting from phosphonoazadienes.
TL;DR: In this paper, the use of cyclic tri-and pentavalent amidoesters and diamides with a stereogenic phosphorus as chiral stoichiometric auxiliaries in asymmetric synthesis is discussed.
Abstract: This review presents the use of cyclic tri- and pentavalent amidoesters and diamides with a stereogenic phosphorus as chiral stoichiometric auxiliaries in asymmetric synthesis. It shows that these compounds are especially useful for the preparation of selected acyclic enantiomerically (diastereomerically) pure (or enriched) tricoordinated-trivalent and tetracoordinated-pentavalent derivatives and as precursors of stereogenic phosphorus-containing carbanions. Their utility in a few other asymmetric reactions is also discussed.
Journal Article•
TL;DR: In this article, Delta Biovalue BV, a major biodiesel manufacturer in the European Union, Corning Incorporated, a manufacturer of modular Advanced-Flow (TM) glass reactors and SynBioC, a research group with a long-standing interest and know-how in flow and renewable chemistry have collaborated to develop a new process aimed at performing the transformation of glycerol in STBE under flow conditions.
Abstract: Glycerol, the main by-product of biodiesel production, has been considered a renewable chemical for large scale production of a new potent fuel-additive, namely solketal tertbutyl ether (STBE). Delta Biovalue BV, a major biodiesel manufacturer in the European Union, Corning Incorporated, a manufacturer of modular Advanced-Flow (TM) glass reactors and SynBioC, a research group with a long-standing interest and know-how in flow and renewable chemistry have collaborated to develop a new process aimed at performing the transformation of glycerol in STBE under flow conditions. The advantages of the highly engineered Corning reactor system, including: high mixing, heat-exchange efficiencies under corrosive flow conditions with low liquid hold-up and high throughput, allowed the development and the intensification of a two-step process with 83 percent global yield. The final goal of this project is to develop a robust, green and safe process being able to produce similar to 12,000 t/y STBE.
Patent•
03 Nov 2010TL;DR: In this article, a 2-azabicyclo[3.1.1]heptyl derivatives, which are useful therapeutic agents for preventing or treating central nervous system disorders and disease mediated by a Nicotinic Acetylcholine Receptor such as, but not limited to, Alzheimer disease, Parkinson's disease, schizophrenia, epilepsy, dementia, pain and nicotine addiction, are presented.
Abstract: This invention provides 2-azabicyclo[3.1.1]heptyl derivatives, and methods for producing them, which are useful therapeutic agents for preventing or treating central nervous system disorders and disease mediated by a Nicotinic Acetylcholine Receptor such as, but not limited to, Alzheimer's disease, Parkinson's disease, schizophrenia, epilepsy, dementia, pain and nicotine addiction.
TL;DR: In this paper, aldehydes were converted to α-chloroaldimines by a sequence of reactions involving conversion into aldimines, chlorination at the α-position, base-induced dehydrochlorination and hydrolysis.
Abstract: The oxidation of aldehydes to α,β-unsaturated aldehydes has been performed by a sequence of reactions involving conversion into aldimines, chlorination at the α-position to form α-chloroaldimines, base-induced dehydrochlorination and hydrolysis. The four-step transformation can be executed without isolation of the intermediates. This method has been applied to the synthesis of an artificial flavor, i.e. 2-butyl-3-phenylpropenal.
TL;DR: A simple procedure for the conversion of hydroxymethyl-furfural (I) to aminomethylfuran-2-yl-methanol is described in this paper.
Abstract: A simple procedure for the conversion of hydroxymethyl-furfural (I) to aminomethylfuran-2-yl-methanol is described.
TL;DR: Aldimines were selectively α-monochlorinated without any interference of α,α-dichlorinated derivatives, by a sequence of reactions involving α-trimethylsilylation of preformed 1-azaenolates, α-chlorination using N-chlorosuccinimide and desilylation in methanol.
Abstract: Aldimines were selectively α-monochlorinated without any interference of α,α-dichlorinated derivatives, by a sequence of reactions involving α-trimethylsilylation of preformed 1-azaenolates, α-chlorination using N-chlorosuccinimide and desilylation in methanol. Upon acidic hydrolysis, these α-monochloroimines provide an easy access to α-monochloroaldehydes.
TL;DR: In this paper, 1-Phosphono-2-aza-1, 3-dienes were formed by 1, 4-dehydro-chlorination of the corresponding α-chloroimines and reacted with diazomethane to give 1-vinyl-2phosphonoaziridines.
Abstract: 1-Phosphono-2-aza-1, 3-dienes were formed by 1, 4-dehydrochlorination of the corresponding N-(phosphonomethyl)-α-chloroimines, and reacted smoothly with diazomethane to give 1-vinyl-2-phosphonoaziridines.
1-Phosphono-2-aza-1, 3-dienes were formed by 1, 4-dehydro-chlorination of the corresponding α-chloroimines and reacted with diazomethane to give 1-vinyl-2-phosphonoaziridines.
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TL;DR: Trialkyl and silylated dialkyl phosphites were evaluated as phosphorus nucleophiles for the addition to quinolines in a strong acidic medium allowing consecutive 1,4 and 1,2-addition breaking up the aromatic stabilisation, thereby leading to 2,4-diphosphono-1,2,3,4,tetrahydroquinolines as discussed by the authors.
Abstract: Trialkyl and silylated dialkyl phosphites were evaluated as phosphorus nucleophiles for the addition to quinolines in a strong acidic medium allowing consecutive 1,4- and 1,2-addition breaking up the aromatic stabilisation, thereby leading to 2,4-diphosphono-1,2,3,4-tetrahydroquinolines in one single reaction step in moderate to good yields (2-84%).
TL;DR: In this article, a two-step synthesis of 1-cyanoisoindoles starting from ethynylbenzaldehyde is presented, where the key step is a mild, high-yielding, gold-catalyzed rearrangement of N-allylic aminonitriles.
Abstract: A two-step synthesis of 1-cyanoisoindoles starting from ethynylbenzaldehyde is presented. The key step is a mild, high-yielding, gold-catalyzed rearrangement of N-allylic aminonitriles.
TL;DR: In this paper, a series of benzo-fused tricyclic β-lactams, most of them phosphonobenzocarbachems, were prepared in a straightforward way starting from phosphonoazadienes.
Abstract: A series of benzo-fused tricyclic β-lactams, most of them phosphonobenzocarbacephems, were prepared in a straightforward way starting from phosphonoazadienes. In this paper, the synthetic route including a Staudinger reaction towards the β-lactams, followed by radical ring closing with tributyltin hydride and AIBN, which resulted in the envisaged tricyclic compounds, is reported.