Daniel Carrié

Over-stabilization of Candida antarctica lipase B by ionic liquids in ester synthesis

Four different ionic liquids, based on dialkylimidazolium cations associated with perfluorinated and bis(trifluoromethyl)sulfonyl amide anions were used as reaction media for butyl butyrate synthesis catalyzed by free Candida antarctica lipase B at 2% (v/v) water content and 50 °C. Lipase had enhanced synthetic activity in all ionic liquids in comparison with two organic solvents (hexane, and 1-butanol), the enhanced activity being related to the increase in polarity of ionic liquids. The continuous operation of lipase with all the assayed ionic liquids showed over-stabilization of the enzyme. The reuse of free lipase in 1-butyl-3-methylimidazolium hexafluorophosphate in continuous operation cycles showed a half-life time 2300 times greater than that observed when the enzyme was incubated in the absence of substrate (3.2 h), and a selectivity higher than 90%.

Lipase Catalysis in Ionic Liquids and Supercritical Carbon Dioxide at 150 °C

Free and immobilized Candida antarctica lipase B dispersed in ionic liquids (1‐ethyl‐3‐methylimidazolium bistriflimide and 1‐buthyl‐3‐methylimidazolium bistriflimide) were used as catalyst for the continuous kinetic resolution of rac‐1‐phenylethanol in supercritical carbon dioxide at 120 and 150 °C and 10 MPa. Excellent activity, stability and enantioselectivity levels were recorded in continuous operation.

Continuous green biocatalytic processes using ionic liquids and supercritical carbon dioxide

Soluble Candida antarctica lipase B dissolved in ionic liquids showed good synthetic activity, enantioselectivity and operational stability in supercritical carbon dioxide for both butyl butyrate synthesis and the kinetic resolution of 1-phenylethanol processes by transesterification.

Enantioselective cyclopropanation reactions in ionic liquids

Abstract The benchmark enantioselective cyclopropanation of styrene with ethyl diazoacetate, promoted by two different bis(oxazoline)-copper complexes, is studied in three ionic liquids. The nature of both the anion and cation influence the behaviour of the catalysts, which can be recovered and re-used.

Ionic liquids based microwave-assisted extraction of lichen compounds with quantitative spectrophotodensitometry analysis

Ionic liquids based extraction method has been applied to the effective extraction of norstictic acid, a common depsidone isolated from Pertusaria pseudocorallina, a crustose lichen. Five 1-alkyl-3-methylimidazolium ionic liquids (ILs) differing in composition of alkyl chain and anion were investigated for extraction efficiency. The extraction amount of norstictic acid was determined after recovery on HPTLC with a spectrophotodensitometer. The proposed approaches (IL-MAE and IL-heat extraction (IL-HE)) have been evaluated in comparison with usual solvents such as tetrahydrofuran in heat-reflux extraction and microwave-assisted extraction (MAE). The results indicated that both the characteristics of the alkyl chain and anion influenced the extraction of polyphenolic compounds. The sulfate-based ILs [C(1)mim][MSO(4)] and [C(2)mim][ESO(4)] presented the best extraction efficiency of norstictic acid. The reduction of the extraction times between HE and MAE (2 h-5 min) and a non-negligible ratio of norstictic acid in total extract (28%) supports the suitability of the proposed method. This approach was successfully applied to obtain additional compounds from other crustose lichens (Pertusaria amara and Ochrolechia parella).

Qualitative and Spatial Metabolite Profiling of Lichens by a LC–MS Approach Combined With Optimised Extraction

INTRODUCTION Lichens are self-sustaining partnerships comprising fungi as shape-forming partners for their enclosed symbiotic algae. They produce a tremendous diversity of metabolites (1050 metabolites described so far). OBJECTIVES A comparison of metabolic profiles in nine lichen species belonging to three genera (Lichina, Collema and Roccella) by using an optimised extraction protocol, determination of the fragmentation pathway and the in situ localisation for major compounds in Roccella species. METHODS Chemical analysis was performed using a complementary study combining a Taguchi experimental design with qualitative analysis by high-performance liquid chromatography coupled with mass spectrometry techniques. RESULTS Optimal conditions to obtain the best total extraction yield were determined as follows: mortar grinding to a fine powder, two successive extractions, solid:liquid ratio (2:60) and 700 rpm stirring. Qualitative analysis of the metabolite profiling of these nine species extracted with the optimised method was corroborated using MS and MS/MS approaches. Nine main compounds were identified: 1 β-orcinol, 2 orsellinic acid, 3 putative choline sulphate, 4 roccellic acid, 5 montagnetol, 6 lecanoric acid, 7 erythrin, 8 lepraric acid and 9 acetylportentol, and several other compounds were reported. Identification was performed using the m/z ratio, fragmentation pathway and/or after isolation by NMR analysis. The variation of the metabolite profile in differently organised parts of two Roccella species suggests a specific role of major compounds in developmental stages of this symbiotic association. CONCLUSION Metabolic profiles represent specific chemical species and depend on the extraction conditions, the kind of the photobiont partner and the in situ localisation of major compounds.

Metalloporphyrin Symmetry in Chiral Recognition and Enantioselective Catalysis

Symmetry plays a fundamental role in chiral recognition and enantioselective catalysis. Porphyrins possess a number of structural features that make them attractive for the stereocontrol of chiral recognition and metal-catalyzed asymmetric reactions. This article is a brief account of our studies on chiral recognition and enantioselective catalysis by optically active metalloporphyrins. Some of the studies on chiral recognition and asymmetric catalysis by metalloporphyrins performed by others have also been included when useful.

Rearrangement of lithioalkynyltriorganoborates derived from propargylic acetals : a one pot synthesis of homopropargylic alcohols

Abstract Lithioalkynyltnorganoborales generated from the corresponding propargylic acetals rearrange in the presence of boron trichloride thus opening an efficient and convenient route to a variety of homopropargylic alcohols free of the corresponding allenic isomers. Unexpectedly, the parent derivative leads exclusively to the allenic alcohol.

Sample preparation for an optimized extraction of localized metabolites in lichens: Application to Pseudevernia furfuracea

Lichens are symbiotic organisms known for producing unique secondary metabolites with attractive cosmetic and pharmacological properties. In this paper, we investigated three standard methods of preparation of Pseudevernia furfuracea (blender grinding, ball milling, pestle and mortar). The materials obtained were characterized by electronic microscopy, nitrogen adsorption and compared from the point of view of extraction. Their microscopic structure is related to extraction efficiency. In addition, it is shown using thalline reactions and mass spectrometry mapping (TOF-SIMS) that these metabolites are not evenly distributed throughout the organism. Particularly, atranorin (a secondary metabolite of interest) is mainly present in the cortex of P. furfuracea. Finally, using microwave assisted extraction (MAE) we obtained evidence that an appropriate preparation can increase the extraction efficiency of atranorin by a factor of five.

Ionic liquid-phase organic synthesis (IoLiPOS) methodology applied to cross aldol reaction

Cross aldol reaction in task-specific ionic liquids was developed. Ionic liquid-phase bound aldehyde reacted with various ketones (acetone, cyclopentanone, and butan-2-one) with l-proline as catalyst to afford various ionic liquid-phase supported aldols in yields ranging from 81 to 99%. Detachment of the aldol in MeOH was realized by transesterification using 15% of MeONa. The structure of intermediates in each step was verified by spectroscopic analysis.