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31.
Carré V Gaud O Sylvain I Bourdon O Spiro M Blais J Granet R Krausz P Guilloton M 《Journal of photochemistry and photobiology. B, Biology》1999,48(1):57-62
A series of neutral meso-arylglycosylporphyrins has been tested in order to evaluate their potency as antifungal agents against the yeast Saccharomyces cerevisiae. Photodynamic activity of these molecules results in intracellular damage as evidenced by the loss of clonogenicity and DNA fragmentation. The ability of these photosensitizers to permeate yeast cells is determined by microspectrofluorimetry and is correlated with their antifungal potency. Amphiphilic porphyrin derivatives are shown to exhibit the more pronounced photoactivity. 相似文献
32.
Marie E Chevalier Y Brunel S Eydoux F Germanaud L Flores P 《Journal of colloid and interface science》2004,269(1):117-125
The mechanism of action of additives that control the sedimentation of paraffin crystals after their crystallization in model diesel oil has been studied by means of a new experimental approach. The chemical analysis of the crystals and detailed measurements of the sedimentation phenomenon give new insights into this complex process. Thus, the wax antisettling additives used for preventing wax crystal sedimentation adsorb at the surfaces of wax particles and provide them with enhanced colloidal stability. The settling rate is not related to the size of the crystals or the viscosity of the liquid medium, but to the ability of the additives to prevent the aggregation of wax crystals. The reported methodology makes it possible to investigate the fundamental mechanisms, but also to evaluate structure-activity relationships of the various additives used in the petroleum industry. 相似文献
33.
Mickaël Pauvert Sylvain C. Collet André Y. Guingant Michel Evain 《Tetrahedron letters》2005,46(17):2983-2987
Addition of cyanide ion to chiral N-acyl-quinolinium and N-acyl-isoquinolinium salts led selectively to 1,2-addition products. Removal of the chiral auxiliary affords the title compounds in pure enantiomeric form. 相似文献
34.
Lahboub Bouyazza Jean-Charles Lancelot Sylvain Rault Max Robba Marie Anne Quermonne 《Journal of heterocyclic chemistry》1991,28(2):373-377
Cyclization of 2-(1-pyrrolyl)piperonylcarboxamide derivatives gave iminium perchlorates which afforded 9-(N-substituted-imino) and 9-(N-substituted amino)-6,7-methylenedioxypyrrolo[1,2-a]indoles. 相似文献
35.
Monique Perrin Sylvain Lecocq 《Journal of inclusion phenomena and macrocyclic chemistry》1991,11(2):171-183
A cyclic pentamer was obtained fromp-(1,1,3,3-tetramethylbutyl) phenol. It crystallizes from a mixture of acetone and toluene at room temperature giving a 1 : 1 complex with toluene (compound A), whereas at 50°C the empty form (compound B) is obtained. Crystals of A are orthorhombic, space groupPna21,a = 20.083(2),b = 12.936(6),c = 28,423(1) Å,Z = 4, finalR value = 0.067. The empty form, B, is monoclinicP21/c,a = 18.695(2),b = 11.673(5),c = 35.100(4) Å, = 114.33(1),Z = 4, finalR value = 0.135. The macrocycle is in the cone conformation for both compounds; the toluene molecule lies in the cone as often found for calix[4]arenes. 相似文献
36.
Michel F Thomas F Hamman S Saint-Aman E Bucher C Pierre JL 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(17):4115-4125
Galactose oxidase (GO) is an enzyme that catalyzes two-electron oxidations. Its active site contains a copper atom coordinated to a tyrosyl radical, the biogenesis of which requires copper and dioxygen. We have recently studied the properties of electrochemically generated mononuclear Cu(II)-phenoxyl radical systems as model compounds of GO. We present here the solution chemistry of these ligands under various copper and dioxygen statuses: N(3)O ligands first chelate Cu(II), leading, in the presence of base, to [Cu(II)(ligand)(CH(3)CN)](+) complexes (ortho-tert-butylated ligands) or [(Cu(II))(2)(ligand)(2)](2+) complexes (ortho-methoxylated ligands). Excess copper(II) then oxidizes the complex to the corresponding mononuclear Cu(II)-phenoxyl radical species. N(2)O(2) tripodal ligands, in the presence of copper(II), afford directly a copper(II)-phenoxyl radical species. Addition of more than two molar equivalents of copper(II) affords a Cu(II)-bis(phenoxyl) diradical species. The donor set of the ligand directs the reaction towards comproportionation for ligands possessing an N(3)O donor set, while disproportionation is observed for ligands possessing an N(2)O(2) donor set. These results are discussed in the light of recent results concerning the self-processing of GO. A path involving copper(II) disproportionation is proposed for oxidation of the cross-linked tyrosinate of GO, supporting the fact that both copper(I) and copper(II) activate the enzyme. 相似文献
37.
Sylvain Celanire Frederic Marlin Jack E. Baldwin Robert M. Adlington 《Tetrahedron》2005,61(12):3025-3032
The synthesis of 3,11-dioxatricyclo[5.3.1.01,5]undeca-5,9-dien-8-ones is reported from suitable 5-substituted furfuryl alcohols bearing an acetylenic side-chain. Successive peracid-mediated oxidative rearrangement of furan carbinols and base-assisted intramolecular 1,3-dipolar cycloaddition afforded oxygen-bridged tricyclo-undecane derivatives. Stereoselective transformations of cycloadducts are also discussed. 相似文献
38.
Frdric Carrel Sylvain Giraud Olivier Spertini Pierre Vogel 《Helvetica chimica acta》2004,87(5):1048-1070
Wittig olefination of (2S,3R,5S,6R)‐5‐(acetyloxy)‐tetrahydro‐6‐[(methoxymethoxy)methyl]‐3‐(phenylthio)‐ 2H‐pyran‐2‐acetaldehyde ((+)‐ 10 ) with {2‐[(2S,3R,4R,5R,6S)‐tetrahydro‐3,4,5‐tris(methoxymethoxy)‐6‐methyl‐ 2H‐pyran‐2‐yl]ethyl}triphenylphosphonium iodide ((?)‐ 11 ) gave a (Z)‐alkene derivative (+)‐ 12 that was converted into (αR,2R,3S,4R,5R,6S)‐tetrahydro‐α,3‐dihydroxy‐2‐(hydroxymethyl)‐5‐(phenylthio)‐6‐{(2Z)‐4‐[(2S,3S,4R,5S,6S)‐tetrahydro‐3,4,5‐trihydroxy‐6‐methyl‐2H‐pyran‐2‐yl]but‐2‐enyl}2H‐pyran‐4‐acetic acid ( 8 ), (αR,2R,3S,4R,6S)‐tetrahydro‐α,3‐dihydroxy‐2‐(hydroxymethyl)‐6‐{4‐[(2S,3S,4R,5S,6S)‐tetrahydro‐3,4,5‐trihydroxy‐6‐methyl‐2H‐pyran‐2‐yl]butyl}‐2H‐pyran‐4‐acetic acid ( 9 ), and simpler analogues without the hydroxyacetic side chain such as (2S,3S,4R,5S,6S)‐tetrahydro‐6‐methyl‐2‐{(2Z)‐4‐[(2S,3R,5S,6R)‐tetrahydro‐5‐hydroxy‐6‐(hydroxymethyl)‐3‐(phenylthio)‐2H‐pyran‐2‐yl]but‐2‐enyl}‐2H‐pyran‐3,4,5‐triol ( 30 ), (2S,3S,4R,5S,6S)‐tetrahydro‐6‐methyl‐2‐{[(2S,5S,6R)‐tetrahydro‐5‐hydroxy‐6‐(hydroxymethyl)‐2H‐pyran‐2‐yl]butyl}‐2H‐pyran‐3,4,5‐ triol ((?)‐ 41 ) and (2S,3S,4R,5S,6S)‐tetrahydro‐6‐methyl‐2‐{(2Z/E))‐4‐[(2R,5S,6R)‐tetrahydro‐5‐hydroxy‐6‐(hydroxymethyl)‐2H‐pyran‐2‐yl]but‐2‐enyl}‐2H‐pyran‐3,4,5‐triol ( 43 ). The key intermediates (+)‐ 10 and (?)‐ 11 were derived from isolevoglucosenone and from L ‐fucose, respectively. The following IC50 values were measured in a ELISA test for the affinities of sialyl Lewis x tetrasaccharide, 8, 9, 30 , (?)‐ 41 , and 43 toward P‐selectin: 0.7, 2.5–2.8, 7.3–8.0, 5.3–5.9, 5.0–5.2, and 3.4–4.1 mM , respectively. 相似文献
39.
Reactions of [M(SR)(3)(PMe(2)Ph)(2)] (M = Ru, Os; R = C(6)F(4)H-4, C(6)F(5)) with CS(2) in acetone afford [Ru(S(2)CSR)(2)(PMe(2)Ph)(2)] (R = C(6)F(4)H-4, 1; C(6)F(5), 3) and trans-thiolates [Ru(SR)(2)(S(2)CSR)(PMe(2)Ph)(2)] (R = C(6)F(4)H-4, 2; C(6)F(5), 4) or the isomers trans-thiolates [Os(SR)(2)(S(2)CSR)(PMe(2)Ph)(2)] (R = C(6)F(4)H-4, 5; C(6)F(5), 7) and trans-thiolate-phosphine [Os(SR)(2)(S(2)CSR)(PMe(2)Ph)(2)] (R = C(6)F(4)H-4, 6; C(6)F(5), 8) through processes involving CS(2) insertion into M-SR bonds. The ruthenium(III) complexes [Ru(SR)(3)(PMe(2)Ph)(2)] react with CS(2) to give the diamagnetic thiolate-thioxanthato ruthenium(II) and the paramagnetic ruthenium(III) complexes while osmium(III) complexes [Os(SR)(3)(PMe(2)Ph)(2)] react to give the paramagnetic thiolate-thioxanthato osmium(III) isomers. The single-crystal X-ray diffraction studies of 1, 4, 5, and 8 show distorted octahedral structures. (31)P [(1)H] and (19)F NMR studies show that the solution structures of 1 and 3 are consistent with the solid-state structure of 1. 相似文献
40.
Cecilia Rodríguez de Barbarín Sylvain Berns Blanca Njera Perla Elizondo 《Acta Crystallographica. Section C, Structural Chemistry》2007,63(10):o597-o599
Two salts of acyclic Schiff base cationic ligands, namely N,N′‐bis(2‐nitrobenzyl)propane‐1,3‐diammonium dichloride monohydrate, C17H22N4O42+·2Cl−·H2O, (I), and 2‐hydroxy‐N,N′‐bis(2‐nitrobenzyl)propane‐1,3‐diammonium dichloride, C17H22N4O52+·2Cl−, (II), were synthesized as precursors in order to obtain new acyclic and macrocyclic multidentate ligands and complexes. The cation conformations in compounds (I) and (II) are different in the solid state, although the cations are closely related chemically. Similarly, the hydrogen‐bonding networks involving ammonium cations, hydroxyl groups and chloride anions are also different. In the cation of compound (II), the hydroxyl group is disordered over two sets of sites, with occupancies of 0.785 (8) and 0.215 (8). 相似文献