Affiner les résultats

Type de document

Institution

Collection spécifique

Langue

Université de Neuchâtel

Optically active liquid-crystalline fullerodendrimers from enantiomerically pure fulleropyrrolidines

Lincker, Frédéric ; Bourgun, Philippe ; Stoeckli-Evans, Helen ; Saez, Isabel M. ; Goodby, John W. ; Deschenaux, Robert

In: Chemical Communications, 2010, vol. 46, no. 40, p. 7522-7524

A synthetic methodology based on the 1,3-dipolar cycloaddition reaction was developed to design enantiomerically pure liquid-crystalline fullerodendrimers.

Université de Neuchâtel

Catalytic Hydrogenation of meso-Octamethylporphyrinogen (Calix[4]pyrrole)

Journot, Guillaume ; Letondor, Christophe ; Neier, Reinhard ; Stoeckli-Evans, Helen ; Savoia, Diego ; Gualandi, Andrea

In: Chemistry - A European Journal, 2010, vol. 16, no. 4, p. 4224-4230

Hydrogenation of meso-octamethylporphyrinogen (calix[4]pyrrole) with a number of heterogeneous catalysts under different experimental conditions has been investigated. GC-MS analyses of the reaction mixtures showed the formation of one to four products in low to moderate yields: three of them were diastereoisomers of the product derived from half-hydrogenation of the substrate, and displayed...

Université de Neuchâtel

rac-Methyl 4-azido-3-hydroxy-3-(2-nitrophenyl)butanoate

Vallat, Oliver ; Buciumas, Ana-Maria ; Neier, Reinhard ; Stoeckli-Evans, Helen

In: Acta Crystallographica Section E : Structure Reports Online, 2009, vol. E65, no. 2, p. o396-o397, sup1-8

In the title compound, C11H12N4O5, the mean plane through the nitro substituent on the benzene ring is inclined to the benzene mean plane by 85.8 (2)°, which avoids steric interactions with the ortho substituents. The hydroxy group is involved in bifurcated hydrogen bonds. The first is an intramolecular O-H···O hydrogen bond, involving the...

Université de Neuchâtel

5-Hydroxyalkyl derivatives of tert-butyl 2-oxo-2,5-dihydro-1H-pyrrole-1-carboxylate: diastereoselectivity of the Mukaiyama crossed-aldol-type reaction

Vallat, Oliver ; Buciumas, Ana-Maria ; Neier, Reinhard ; Stoeckli-Evans, Helen

In: Acta Crystallographica Section C : Crystal Structure Communications, 2009, vol. C65, no. 4, p. o171-o175

The title compounds, rac-(1'R,2R)-tert-butyl 2-(1'-hydroxyethyl)-3-(2-nitrophenyl)-5-oxo-2,5-dihydro-1H-pyrrole-1-carboxylate, C17H20N2O6, (I), rac-(1'S,2R)- tert-butyl 2-[1'-hydroxy-3'-(methoxycarbonyl)propyl]-3-(2-nitrophenyl)-5-oxo-2,5-dihydro-1H-pyrrole-1-carboxylate,...

Université de Neuchâtel

2-(2-Naphthyl)-1,3-dioxane

Thevenet, Damien ; Neier, Reinhard ; Stoeckli-Evans, Helen

In: Acta Crystallographica Section E : Structure Reports Online, 2010, vol. E66, no. 2, p. o473-o474, sup1-8

The title compound, C14H14O2, crystallizes in the chiral monoclinic space group P21. 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 molecules are connected via a weak C-H ··· O interaction to form a helical chain propagating in [010]. While there are...

Université de Neuchâtel

4,4-Bis(1H-pyrrol-2-yl)pentanol

Journot, Guillaume ; Neier, Reinhard ; Stoeckli-Evans, Helen

In: Acta Crystallographica Section E : Structure Reports Online, 2010, vol. E66, no. 2, p. o393, sup1-8

The title achiral compound, C13H18N2O, crystallized in the chiral monoclinic space group P21. The pyrrole rings are inclined to one another by 62.30 (11)°, and the propanol chain is in an extended conformation. In the crystal, the two pyrrole NH groups are involved in intermolecular N-H ··· O hydrogen bonds, leading to the formation of a...

Université de Neuchâtel

2,2'-(Propane-2,2-diyl)bis(1H-pyrrole)

Journot, Guillaume ; Neier, Reinhard ; Stoeckli-Evans, Helen

In: Acta Crystallographica Section E : Structure Reports Online, 2010, vol. E66, no. 2, p. o392, sup1-9

The title compound, C11H14N2, crystallized with two independent molecules (A and B) in the asymmetric unit. The two molecules differ only slightly, with the pyrrole rings being inclined to one another at a dihedral angle of 87.67 (8)° in molecule A and 88.09 (7)° in molecule B. In the crystal, there are no classical hydrogen bonds,...

Université de Neuchâtel

Application of the Novel Tandem Process Diels-Alder Reaction/Ireland-Claisen Rearrangement to the Synthesis of rac-Juvabione and rac-Epijuvabione

Soldermann, Nicolas ; Velker, Joerg ; Vallat, Olivier ; Stoeckli-Evans, Helen ; Neier, Reinhard

In: Helvetica Chimica Acta, 2000, vol. 83, no. 9, p. 2266-2276

The novel tandem process Diels-Alder reaction/Ireland-Claisen rearrangement shows a high diastereoselectivity for the Ireland-Claisen rearrangement starting from the endo-product of the Diels-Alder reaction. Based on this mechanistic knowledge, the novel tandem process could be applied to the synthesis of rac-juvabione.

Université de Neuchâtel

Rac-(2R*,3R*)-S-Ethyl-4-Chloro-3-Hydroxy-2-Phenylbuthanethioate and Rac-(2R*,3R*)-S-Ethyl-2-Phenyl-3-(tosyloxy)buthanethioate: Dichotomy of the Stereoselectivity of the Mukaiyama Reaction

Vallat, Oliver ; Buciumas, Ana-Maria ; Neier, Reinhard ; Stoeckli-Evans, Helen

In: Journal of Chemical Crystallography, 2009, vol. 40, no. 1, p. 10-14

The title compounds, rac-(2R*,3R*)-S-ethyl-4-chloro-3-hydroxy-2-phenylbuthanethioate (I) and rac-(2R*,3R*)-S-ethyl-2-phenyl-3-(tosyloxy)buthanethioate (III), are both composed of a S-ethyl 2-phenylbutanethioate moiety but have different geometries. Compound I is substituted in the 3 and 4 positions by a hydroxyl group and a chlorine atom, respectively. In compound III...