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Your search keyword '"Penverne, Christophe"' showing total 13 results
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13 results on '"Penverne, Christophe"'

1. Rapid and sensitive quantification of C3- and C6-phosphoesters in starch by fluorescence-assisted capillary electrophoresis

Author

Verbeke, Jérémy, Penverne, Christophe, d'Hulst, Christophe, Rolando, Christian, and Szydlowski, Nicolas

Subjects
Quantitative Biology - Biomolecules
Abstract

Phosphate groups are naturally present in starch at C3- or C6-position of the glucose residues and impact the structure of starch granules. Their precise quantification is necessary for understanding starch physicochemical properties and metabolism. Nevertheless, reliable quantification of Glc-3-P remains laborious and time consuming. Here we describe a capillary electrophoresis method for simultaneous measurement of both Glc-6-P and Glc-3-P after acid hydrolysis of starch. The sensitivity threshold was estimated at the fg scale, which is compatible with the analysis of less than a $\mu$g of sample. The method was validated by analyzing antisense potato lines deficient in SBEs, GWD or GBSS. We show that Glc-3-P content is altered in the latter and that these variations do not correlate with modifications in Glc-6-P content. We anticipate the method reported here to be an efficient tool for high throughput study of starch phosphorylation at both C3- and C6-position.

Published
2019
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3. Chemistry of natural alpha-amino acids: a surprising ''one-pot four-step'' conversion of polyfunctional enones into cyclic imines

Author

Amigoni, Sonia, Penverne, Christophe, Nugier-Chauvin, Caroline, and Le Floc'h, Yves

Subjects
Chemistry -- Study and teaching, Carbonyl compounds -- Research, Cyclic compounds -- Research, Amino acids -- Observations, Chemistry, Education, Science and technology
Abstract

Chemistry of natural alpha-amino acids is discussed. A surprising multistep conversion of polyfunctional enones into cyclic imines has been found and is especially suitable for a graduate organic chemistry laboratory class, where it will take students five 8-hour periods. .

Published
1999

8. Synthesis of 4-methylumbellifer-7-yl-alpha-D-mannopyranoside: an introduction to modern glycosylation reactions

Author

Penverne, Christophe and Ferrieres, Vincent

Subjects
Biochemistry -- Study and teaching, Glycosylation -- Study and teaching, Polyols -- Study and teaching, Chemistry, Education, Science and technology
Abstract

Fourth-year organic chemistry students can learn about modern glycosylation reactions by carrying out the 4-step synthesis of 4-methylumbellifer-7-yl-alpha-D-mannopyranoside. Students find the lab exciting because they are introduced to the interpretation of 2D-NMR spectra and because reaction times are very short. The target is mannosylated coumarin and it was prepared, apparently for the first time, using the trichloroacetimidate method in the development of this exercise. Glycochemistry is increasingly of interest, being attractive for biological, medical, and pharmaceutical applications. Two 4-hour labs are needed.

Published
2002

11. Scale-up Study of Benzoic Acid Alkylation in Flow: From Microflow Capillary Reactor to a Milliflow Reactor

Author

Penverne, Christophe, Hazard, Benjamin, Rolando, Christian, and Penhoat, Maël

Abstract

The esterification reaction is one of the most important reaction in organic chemistry, and the development of scalable continuous flow conditions is of high interest. Here we describe a scaling-up study of benzoic acid alkylation by MeI in the presence of superbases from a capillary reactor (282 mg·h–1at 75 °C) to a low flow reactor (LFR, 6.82 g·h–1at 80 °C). First, the optimization of the base demonstrated that 1,8-diazabicyclo[5.4.0]-undec-7-ene (DBU) was a good compromise in terms of basicity and price. A comparison between batch and LFR reaction showed similar kinetic rates. We also observed a maximum reactivity for a flow rate of 3 mL·min–1which corresponds to an optimum mixing of the entering fluids. A colorimetric study permits to show a visual change in the flow regime (dispersed to stratified) by varying the flow rate with a maximum conversion obtained at 3 mL·min–1corresponding to a 105 s residence time, demonstrating that the studied reaction is sensitive to mixing conditions and that LFR presents some mixing limitations for low flow rates. After thermal optimization (80 °C), the reaction has been improved to a productivity of 6.82 g/h at the lab scale using DBU as the base and Eyring/Arrhenius plots permitted to extract activation energies.

Published
2024
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12. Chemistry of natural alpha-amino acids: A surprising `one-pot four-step' conversion of....

Author

Amigoni, Sonia and Penverne, Christophe

Subjects
*CARBONYL compounds, *IMINES, *AMINO acids
Abstract

Examines the conversion of polyfunctional enones into cyclic imines. Synthesis of enones; Protection of amino group as a benzylcarbamate and obtaining the Z-aminoesters; Reduction of Z-protected amino esters 5a-c to aldehydes 6a-c; Hydrogenation and hydrogenolysis of the enones; Application of analytical apparatus in conducting the experiment.

Published
1999
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13. Synthesis of 4-Methylumbellifer-7yl-α-D-Mannopyranoside.

Author

Penverne, Christophe and Ferrières, Vincent

Subjects
*ORGANIC chemistry education, *MAGNETIC resonance imaging, *CHEMICALS
Abstract

Describes the synthesis suitable for a undergraduate organic chemistry laboratory class consisting of fourth-year organic chemistry students. Use of the efficiency glycosyl donor; Interpretation of 2D-NMR spectra; Physical and chemical properties of chemicals.

Published
2002
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