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Stoeckli-Evans, Helen
Nom
Stoeckli-Evans, Helen
Affiliation principale
Fonction
Professeur.e émérite
Email
helen.stoeckli-evans@unine.ch
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Résultat de la recherche
Voici les éléments 1 - 10 sur 21
- 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 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-(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)]
- PublicationMétadonnées seulement2-(2-Naphthyl)-1,3-dioxane(2010)
; ; The title compd., C14H14O2, crystallizes in the chiral monoclinic space group P21. Crystallog. data and at. coordinates are given. This acetal is composed of a planar naphthalene ring with a 1,3-dioxane ring substituent, which has a chair conformation. In the crystal structure, symmetry-related mols. are connected via a weak C-H...O interaction to form a helical chain propagating in [010]. While there are no ?-? stacking interactions present, there are weak C-H...? interactions involving the naphthalene arom. rings, which link the helical chains to form a two-dimensional network in the (011) plane. [on SciFinder(R)] - PublicationMétadonnées seulement4,4-Bis(1H-pyrrol-2-yl)pentanolThe achiral 4,4-bis(1H-pyrrol-2-yl)pentanol, C13H18N2O, crystd. in the chiral monoclinic space group P21. The pyrrole rings are inclined to 1 another by 62.30(11)°, and the PrOH chain is in an extended conformation. In the crystal, the 2 pyrrole NH groups are involved in intermol. N-H···O H bonds, giving a helical arrangement propagating along the b axis. An interesting feature of the crystal structure is the absence of any conventional H bonds involving the hydroxy H atom. There is a weak intermol. O-H···? interaction involving 1 of the pyrrole rings. Crystallog. data are given. [on SciFinder(R)]
- PublicationMétadonnées seulement1,4-Bis(hexyloxy)-2,5-diiodobenzene(2010)
; ; - PublicationMétadonnées seulement2,2'-(Propane-2,2-diyl)bis(1H-pyrrole)2,2'-(Propane-2,2-diyl)bis(1H-pyrrole), C11H14N2, crystd. with 2 independent mols. (A and B) in the asym. unit. The 2 mols. differ only slightly, with the pyrrole rings being inclined to 1 another at a dihedral angle of 87.67(8)° in mol. A and 88.09(7)° in mol. B. In the crystal, there are no classical H bonds, but the 2 pyrrole NH groups of 1 mol. are involved in N-H···? interactions with the pyrrole rings of the other mol. In this manner, a compact box-like arrangement of the 2 independent mols. is formed. Crystallog. data are given. [on SciFinder(R)]
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