A Simple Preparation of 3,5,6-Substituted 2-Cyclohexene-1-Ones and Several Derivatives of 3,4-Diphenyl-5-Oxohexanoic Acid

Some 3,5,6-triaryl-2-cyclohexene-1-ones and derivatives of 3,4-diphenyl-5-oxohexanoic acid are prepared by addition of phenylacetone to α,β-unsaturated compounds in DMSO under the action of aq. NaOH.     

Solid-state molecular organization and solution behavior of methane-1,1-diphosphonic acid derivatives of heterocyclic amines: the role of the topochemical ring modification and the intramolecular hydrogen bonds in monosubstituted piperid-1-ylmethane-1,1-diphosphonic acids

The crystal structures of 3-methylpiperid-1-ylmethane-1,1-diphosphonic (2), 4-methylpiperid-1-ylmethane-1,1-diphosphonic (3), 2-ethylpiperid-1-ylmethane-1,1-diphosphonic (4), and 2-methylpiperid-1-ylmethane-1,1-diphosphonic (5) acids have been determined and are discussed with respect to their molecular organization and crystal-packing preferences. The chair conformation, predominant also in solution, favors equatorial positioning of the bulky substituents of the heterocyclic N and C atoms. The molecular geometry also provides access to intramolecular hydrogen-bond formation between the axial protons located on the nitrogen atoms, as well as the carbon atoms closest to it, and phosphonic/phosphonate oxygen atoms. The molecules preferably arrange in monolayers, observed in all crystals with an exception of 3. The layers are held in place in the third direction through van der Waals interactions. The analysis of two-dimensional hydrogen-bonded networks is concentrated on revealing how the substituent's topology of the molecule affects the solid-state organization in well-defined structures and is aimed at unraveling the consequences and the possible conformational changes by stepwise network disruption upon crystal dissolution in water. The solution NMR studies are focused on revealing the role that the topochemistry of the substituent plays for the stereodynamics in 2-5. It is demonstrated that in contrast to piperid-1-ylmethane-1,1-diphosphonic acid (1), in which the ring inversion/rotation around the C-N bond concerted with the N-H...O hydrogen-bond breaking/formation process leads to a mixture of two interconverting conformers, the concerted N-H...O breaking/rotation/N-H...O formation process in 2 and 3 allows for a predominance of one conformer in solution. However, placement of a substituent at 2-position in the ring hampers the rotation around the C-N bond; this makes 4 and 5 significantly less flexible relative to compounds 1-3. In addition, both compounds 4 and 5 are proved to exist as a mixture of two conformers, the equilibrium of which in acidic solution is shifted towards the conformer found in solid state. In alkaline solutions of 4 and 5, the equilibrium is shifted towards the conformer that is forced by the flipping of the heterocyclic ring. These results correlate well with recently documented differences in the biological potency of this group of compounds.     

Urea-glutaric acid (2∶1) structural aggregates as building blocks for crystal engineering

The crystal structure of a 21 urea-glutaric acid cocrystal has been determined. The crystal is monoclinic:C2lc,a=11.954(5),b=10.932(1),c=9.078(3) Å, =97.86(3)°, withZ=4. The formula unit is a hydrogen-bonded heterotrimeric aggregate consisting of one acid subunit locked between two identical urea subunits. The symmetric arrangement from both sides of the acid allows for retaining the twofold axis primary inherent for the glutaric acid. An additional symmetry element (inversion center) is introduced during the aggregate self-association into one-dimensional chains, which are further organized through glide operations into a well-defined three-dimensional, hydrogen-bonded crystal network.Deceased on June 10, 1992.     

The supramolecular architecture of tris(naphthalene‐1,5‐diaminium) bis(5‐aminonaphthalen‐1‐aminium) octakis[hydrogen (5‐carboxypyridin‐3‐yl)phosphonate]

The asymmetric unit of the title compound, 3C₁₀H₁₂N₂²⁺·2C₁₀H₁₁N₂⁺·8C₆H₅NO₅P⁻, contains one and a half naphthalene‐1,5‐diaminium cations, in which the half‐molecule has inversion symmetry, one 5‐aminonaphthalen‐1‐aminium cation and four hydrogen (5‐carboxypyridin‐3‐yl)phosphonate anions. The crystal structure is layered and consists of hydrogen‐bonded anionic monolayers between which the cations are arranged. The acid monoanions are organized into one‐dimensional chains along the [101] direction via hydrogen bonds established between the phosphonate sites. (C)O—H...N_py hydrogen bonds (py is pyridine) crosslink the chains to form an undulating (010) monolayer. The cations serve both to balance the charge of the anionic network and to connect neighbouring layers via multiple hydrogen bonds to form a three‐dimensional supramolecular architecture.     

Vanadium oxide gels as electrode materials for lithium batteries

Electrochemical lithium insertion has been studied in a large number of vanadium oxides with three dimensional framework structure. Several of these oxides have shown high capacities for lithium insertion and good reversibility.Pure solutions of decavanadic acid have shown to undergo spontaneous polycondensation reaction forming sols or gels of highly polymerized vanadium oxides, M _w 10⁶. After dehydration a series of xerogels with varying amounts of water, V₂O₅ · nH₂O, can be obtained. The structure of these xerogels consists of ribbons of corner and edge sharing VO₆ octahedra stabilized by interlayer water molecules. Under ambient conditions the water content corresponds to n=1.8, but this value can be reversibly changed under mild drying conditions.This report deals with the electrochemical insertion of lithium in dried vanadium oxide xerogels, with special regard to the use of these materials as electrodes in rechargeable lithium batteries.     

Phase-Transfer Catalyzed Additions. VI. Reaction of N-Diphenylmethyleneaminoacetonitrile with Aromatic Aldehydes

The phase-transfer catalyzed reaction of N-diphenylmethyleneaminoacetonitrile with aromatic aldehydes affords 4-aryl-3-cyano-1,1-diphenyl-2-aza-1,3-butadienes (3) in good yields.