80191-01-1Relevant articles and documents
Guest inclusion in cyclic imides containing flexible tethers
Singh, Devendra,Baruah, Jubaraj B.
, p. 269 - 281 (2013)
Guest inclusion properties of two cyclic imides which have carboxylic acids connected through flexible tether, namely, 4-(1,3-dioxo-1,3-dihydro-isoindol-2- ylmethyl)-cyclohexanecarboxylic acid (1) and 4-(1,3-dioxo-1H,3H-benzo[de] isoquinolin-2-ylmethyl)-cyclohexanecarboxylic acid (2) are studied. The crystals of host 1 containing one molecule of 1, the crystals of 4,4′-bipyridine (bpy) cocrystal of 1 containing one molecule of 1 and half molecule of bpy (1a), the crystals of 1,4-dioxane solvate of 1 containing two molecule of 1 and one and half molecule of 1,4-dioxane (1b) and the crystals of quinoline solvate of 1 containing one molecule of 1 and one molecule of quinoline (1c) in their crystallographic asymmetric units are investigated. Intermolecular hydrogen bonded two dimensional (2D) sheet structure of 1 and 3D channel network of 1b are comprised of cyclic R 2 2 (8) hydrogen bond motifs; whereas cleavage of dimeric carboxylic acid R 2 2 (8) motifs occurs in the structures of 1a and 1c in which 3D host-guest networks are comprised of discrete O-H···N and cyclic R 2 2 (7) interactions, respectively. Various types of weak interactions between the two symmetry nonequivalent host molecule are found to be responsible for the formation of channels (14 × 11 A) filled by guest 1,4-dioxane molecules in the crystal lattice of 1b. Two different solvates of 2 containing one molecule of 2 with a water molecule (2a) and one molecule of 2 with a quinoline molecule (2b) in their crystallographic asymmetric units, respectively, are also crystallized in different space groups. The quinoline molecules are held with host molecules by discrete O-H···N and C-H···O interactions and reside inside the voids formed by 3D repeated hexameric assemblies of host molecules in the crystal lattice of 2b.
Synthesis of Medium- and Large-Ring Compounds Initiated by Photochemical Decarboxylation of ω-Phthalimidoalkanoates
Griesbeck, Axel G.,Henz, Andreas,Kramer, Wolfgang,Lex, Johann,Nerowski, Frank,Oelgemoeller, Michael,Peters, Karl,Peters, Eva-Maria
, p. 912 - 933 (2007/10/03)
The synthesis of a variety of hydroxylactams from ω-phthalimidoalkanoates using a triplet-sensitized photodecarboxylation reaction initiated by intramolecular photo electron transfer is described. Ring sizes available by this method span from 4 (benzazepine-1,5-dione 7) to 26 (cyclodipeptide 26e). Ground-state template formation is proposed as the explanation for the high efficiency of this reaction and for the decrease in reactivity in the presence of organic bases instead of metal carbonates. The crucial step in this macrocyclization reaction seems to be the protonation of the intermediary ketyl radiais (Scheme 4). Spacer groups investigated were alkyl chains (C3-C11: 5c-h, 11a, 12), ether (16, 18), ester (20, 22), and amide (26a-f) linkages. Within the detection limits, no dimeric (= decarboxylative coupling) products were observed, indicating the high preference for intra-vs. intermolecular photoelectron transfer. The C,C radical combination step proceeds with low stereoselectivity (cf. products 11 and 12) in contrast to comparable singlet reactions. Except for the lactones 22, all products were stable under the photolysis conditions. Prolonged irradiation of 22 led to the formation of the spiro compounds 23, probably via an intermediary acyliminium betaine (Scheme 8). One serious limitation of the decarboxylative macrocyclization is its incompatibility with the glycine spacer (as in 27a and 27b), probably the consequence of a strong intramolecular H-bond (Scheme 10).
