Voici les éléments 1 - 10 sur 18
  • Publication
    Métadonnées seulement
    4-Meth-oxy-benzoyl-meso-octa-methyl-calix[2]pyrrolidino[2]pyrrole: an acyl chloride derivative of a partially reduced calix[4]pyrrole
    In 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].
  • Publication
    Métadonnées seulement
    2,2'-[(2S*,6R*)-Piperidine-2,6-diyl]dipropan-2-ol
    In 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)]
  • Publication
    Métadonnées seulement
    The hydrogenation of heterocyclic calix[4]arenes, a transformation leading to novel macrocyclic ligands
    (2012) ;
    Jones, Christopher R.
    ;
    Blangy, Valeria
    ;
    A review. Hydrogenation reactions of calix[4]furan and calix[4]pyrrole were reviewed together with the authors' own work in this field. A short description of the metal binding process of our new calix[4]pyrrolidines (= the fully satd. calix[4]pyrrole) with Cu was discussed as a typical example of the metal binding capacities. The new calix[4]pyrrolidines can be structurally classified as new stiffened macrocyclic crown ethers or as satd. analogs of the porphyrin-derived "pigments of life". [on SciFinder(R)]
  • Publication
    Métadonnées seulement
    4-Chloro-benzoyl-meso-octa-methyl-calix[2]pyrrolidino[2]pyrrole: an acyl chloride derivative of a partially reduced calix[4] pyrrole
    In 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.
  • Publication
    Accès libre
    Catalytic Hydrogenation of meso-Octamethylporphyrinogen (Calix[4]pyrrole)
    (2010) ;
    Letondor, Christophe
    ;
    ; ;
    Savoia, Diego
    ;
    Gualandi, Andrea
    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 alternating pyrrolidine and pyrrole rings, while the fourth was the all-cis saturated product. An acidic medium was necessary to achieve hydrogenation. However, the use of too strongly acidic solvents or additives was detrimental to the stability of the substrate and/or the catalyst.
  • Publication
    Métadonnées seulement
    2,2'-(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)]
  • Publication
    Accès libre
    4,4-Bis(1H-pyrrol-2-yl)pentanol
    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 helical arrangement propagating along the b axis. An interesting feature of the crystal structure is the absence of any conventional hydrogen bonds involving the hydroxy H atom. There is, however, a weak intermolecular O-H ··· π interaction involving one of the pyrrole rings.
  • Publication
    Métadonnées seulement
    Synthesis of α,β'- and β,β'-linked dimethoxycarbonyldipyrromethanes by Rothemund-type condensation
    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)]
  • Publication
    Métadonnées seulement
    4,4-Bis(1H-pyrrol-2-yl)penta-nol
    The title achiral compound, C(13)H(18)N(2)O, crystallized in the chiral monoclinic space group P2(1). 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 inter-molecular N-H(midline ellipsis)O hydrogen bonds, leading to the formation of a helical arrangement propagating along the b axis. An inter-esting feature of the crystal structure is the absence of any conventional hydrogen bonds involving the hydr-oxy H atom. There is, however, a weak inter-molecular O-H(midline ellipsis)? inter-action involving one of the pyrrole rings.
  • Publication
    Métadonnées seulement
    4-Chlorobenzoyl-meso-octamethylcalix[2]pyrrolidino[2]pyrrole: an acyl chloride derivative of a partially reduced calix[4] pyrrole
    In 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)]