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Stoeckli-Evans, Helen
Nom
Stoeckli-Evans, Helen
Affiliation principale
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Professeur.e émérite
Email
helen.stoeckli-evans@unine.ch
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Voici les éléments 1 - 10 sur 187
- PublicationMétadonnées seulementSynthesis of α,β'- and β,β'-linked dimethoxycarbonyldipyrromethanes by Rothemund-type condensation(2012-7-15)
; ; The Rothemund-type condensation of methoxycarbonylpyrrole with acetone produces mainly the α,β'-linked dipyrromethane, a building block for the synthesis of N-confused macrocycles. The influence of the reaction conditions on the regioselectivity of the process is reported. The x-ray structures of the α,α'-, α,β'- and β,β'-linked dipyrromethanes show an interesting discrimination of the structurally different types of hydrogen bonds. [on SciFinder(R)] - PublicationMétadonnées seulement2,2'-[(2S*,6R*)-Piperidine-2,6-diyl]dipropan-2-olIn the title compd., C11H23NO2, the piperidine ring has a chair conformation. The two hydroxy H atoms are disordered over two positions with fixed occupancy ratios of 0.57:0.43 and 0.63:0.37. In the mol., there are two short N-H···O interactions. In the crystal, four symmetry-related mols. are linked by O-H···O H bonds to form a cage-like arrangement, centered about the point of intersection of three 2-fold axes. These cages stack along the [100] direction. Crystallog. data and at. coordinates are given. [on SciFinder(R)]
- PublicationMétadonnées seulement4-Meth-oxy-benzoyl-meso-octa-methyl-calix[2]pyrrolidino[2]pyrrole: an acyl chloride derivative of a partially reduced calix[4]pyrroleIn the title compound, C(36)H(50)N(4)O(2), the two pyrrolidine rings have envelope conformations. The conformation of the macrocycle is stabilized by N-H(midline ellipsis)N hydrogen bonds and a C-H(midline ellipsis)N inter-action. The benzoyl ring is inclined to an adjacent pyrrole ring by 6.76 (9)°, with a centroid-to-centroid distance of 3.6285 (10) Å. In the crystal, apart from a C-H(midline ellipsis)O and a C-H(midline ellipsis)? inter-action, mol-ecules are linked via an N-H(midline ellipsis)O hydrogen bond, leading to the formation of helical chains propagating along [010].
- PublicationMétadonnées seulement4-Chloro-benzoyl-meso-octa-methyl-calix[2]pyrrolidino[2]pyrrole: an acyl chloride derivative of a partially reduced calix[4] pyrroleIn the title compound, C(35)H(47)ClN(4)O, the two pyrrolidine rings have envelope conformations. The conformation of the macrocycle is stabilized by N-H(midline ellipsis)N hydrogen bonds and a C-H(midline ellipsis)N inter-action. The benzoyl ring is inclined to the adjacent pyrrole ring by 11.66 (11)°, with a centroid-centroid distance of 3.7488 (13) Å. In the crystal, molecules are linked by N-H(midline ellipsis)O hydrogen bonds into helical chains propagating in [010] and C-H(midline ellipsis)O and C-H(midline ellipsis)? interactions are also observed.
- PublicationMétadonnées seulementSynthesis and Reactions of 2-[1-Methyl-1-(pyrrolidin-2-yl)ethyl]-1H-pyrrole and Some Derivatives with Aldehydes: Chiral Structures Combining a Secondary-Amine Group with an 1H-Pyrrole Moiety as Excellent H-Bond Donor(2012)
; ; ; The synthesis of compd. I (R = H) and its derivs. I (R = CF3, CO2Me) combining a pyrrolidine ring with an 1H-pyrrole unit is described. Their attempted usability as organocatalysts was not successful. Reacting these simple pyrrolidine derivs. with (E)-cinnamaldehyde led to tricyclic products. The final, major products were the pyrroloindolizidine tricycles, e.g. II, obtained via the iminium ion reacting intramolecularly with the nucleophilic ?-position of the 1H-pyrrole moiety. [on SciFinder(R)] - PublicationMétadonnées seulementCatalytic Epoxidation of Alkenes by the Manganese Complex of a Reduced Porphyrinogen Macrocycle(2012)
; ; The present paper details the first application of a fully reduced meso-octamethylporphyrinogen macrocycle as an effective ligand for simple operative manganese-catalyzed alkene epoxidn. The efficiency of the novel catalyst was detd. in the presence of various oxidants, apical ligands and acidic/basic additives. Higher reactivity was found in favor of electron-rich alkenes, whereas an electron-deficient conjugated alkene appeared to be a poor substrate in the screening. Sulfur additives were active as apical ligands, whereas nitrogen-contg. additives influenced the reactivity only moderately. Cis-Stilbene and 3?-acetoxy-5-cholestene were epoxidized in a stereoselective manner. The x-ray structures of the new manganese complexes were detd. and showed a rigid planar coordination geometry of the satd. macrocyclic ligand to the metal center. [on SciFinder(R)] - PublicationMétadonnées seulement4-Methoxybenzoyl-meso-octamethylcalix[2]pyrrolidino[2]pyrrole: an acyl chloride derivative of a partially reduced calix[4]pyrroleIn the title compd., C36H50N4O2, the two pyrrolidine rings have envelope conformations. The conformation of the macrocycle is stabilized by N-H···N H bonds and a C-H···N interaction. The benzoyl ring is inclined to an adjacent pyrrole ring by 6.76(9)°, with a centroid-to-centroid distance of 3.6285(10) Å. In the crystal, apart from a C-H···O and a C-H···? interaction, mols. are linked via an N-H···O H bond, giving helical chains propagating along [010]. Crystallog. data and at. coordinates are given. [on SciFinder(R)]
- PublicationMétadonnées seulement4-Chlorobenzoyl-meso-octamethylcalix[2]pyrrolidino[2]pyrrole: an acyl chloride derivative of a partially reduced calix[4] pyrroleIn the title compd., C35H47ClN4O, the two pyrrolidine rings have envelope conformations. The conformation of the macrocycle is stabilized by N-H···N H bonds and a C-H···N interaction. The benzoyl ring is inclined to the adjacent pyrrole ring by 11.66(11)°, with a centroid-centroid distance of 3.7488(13) Å. In the crystal, mols. are linked by N-H···O H bonds into helical chains propagating in [010] and C-H···O and C-H···? interactions are also obsd. [on SciFinder(R)]
- PublicationMétadonnées seulement2,2'-[(2S*,6R*)-Piperidine-2,6-di-yl]-di-pro-pan-2-olIn the title compound, C(11)H(23)NO(2), the piperidine ring has a chair conformation. The two hy-droxy H atoms are disordered over two positions with fixed occupancy ratios of 0.57:0.43 and 0.63:0.37. In the mol-ecule, there are two short N-H(midline ellipsis)O inter-actions. In the crystal, four symmetry-related mol-ecules are linked by O-H(midline ellipsis)O hydrogen bonds to form a cage-like arrangement, centered about the point of inter-section of three twofold axes. These cages stack along the [100] direction.
- PublicationMétadonnées seulement2-[2-(Pyrrolidin-2-yl)propan-2-yl]-1H-pyrrole and its amide derivative 1-{2-[2-(1H-pyrrol-2-yl)propan-2-yl]pyrrolidin-1-yl}ethanoneIn the title compds., C11H18N2, (II), and C13H20N2O, (III), the pyrrolidine rings have twist conformations. Compd. (II) crystallizes with two independent mols. (A and B) in the asym. unit. The mean planes of the pyrrole and pyrrolidine rings are inclined to one another by 89.99 (11) and 89.35 (10)° in mols. A and B, resp. In (III), the amide deriv. of (II), the same dihedral angle is much smaller, at only 13.42 (10)°. In the crystal structure of (II), the individual mols. are linked via N-H···N hydrogen bonds to form inversion dimers, each with an R22(12) graph-set motif. In the crystal structure of (III), the mols. are linked via N-H···O hydrogen bonds to form inversion dimers with an R22(16) graph-set motif. [on SciFinder(R)]