Efficient synthesis of 2-aminoindane-2-carboxylic acid via dialkylation of nucleophilic glycine equivalent

An efficient, easy to scale-up method for preparing 2-aminoindane-2-carboxylic acid via two-step alkylation of a Ni(II)-complex of glycine Schiff base with 2-[N-(alpha-picolyl)amino]benzophenone (PAAP) (2b) with o-dibromoxylylene (3) is reported. The first step, monoalkylation of 2b with 3, conducted under phase-transfer conditions, gave the corresponding complex 6 in excellent chemical yield (97.2%). Without any purification the intermediate 6 was cyclized under homogeneous conditions (DMF, NaO-t-Bu) to give the product 7 in high chemical yield (93.1%). Decomposition of prepared 7 afforded the target amino acid 2-aminoindane-2-carboxylic acid (1) in 97.9% yield, along with recovery of ligand 8, which was converted back to the starting glycine complex 2b. Operationally convenient experimental procedures, mild reaction conditions, as well as high chemical and volume yields render the method practical for preparing amino acid 1 and its analogues.     

Recent Reviews. 42

Reviews are listed in order of appearance in the sources indicated. In multidisciplinary review journals, only those reviews which fall within the scope of this Journal are included. Sources are listed alphabetically in three categories: regularly issued review journals and series volumes, contributed volumes, and other monographs. Titles are numbered serially, and these numbers are used for reference in the index. Major English-language sources of critical reviews are covered. Encyclopedic treatises, annual surveys such as Specialist Periodical Reports, and compilations of symposia proceedings are omitted. This installment of Recent Reviews covers principally the middle part of the 1996 literature. Previous installment: J. Org. Chem.1996, 61(14), 4860-8. These Recent Review articles are now also available in a database form on the ACS Organic Division WWW site http://www.organic.emory.edu/acsorg/index.html.     

On microfunctions at the boundary along CR manifolds

Let X be a complex analytic manifold, a C ² submanifold, an openset with C ² boundary .Denote by (resp. ) the microlocalization along M (resp. ) of the sheaf of holomorphic functions.In the literature (cf. [A-G], [K-S 1,2])one encounters two classical results concerning the vanishing of the cohomology groups .The most general gives the vanishing outside a range of indices j whose length is equal to (with being the number of respectively positive, negative and null eigenvalues for themicrolocal Levi form ).The sharpest result gives the concentration in a single degree, provided that the difference is locally constant for near p (with for z the base point of p).The first result was restated for the complex in [D'A-Z 2], in the case codim We extend it here to any codimension and moreover we also restate for the second vanishing theorem.We also point out that the principle of our proof, related to a criterion for constancy of sheaves due to [K-S 1], is a quite new one.     

Luminescent lanthanide ions hosted in a fluorescent polylysin dendrimer. Antenna-like sensitization of visible and near-infrared emission

We have investigated the complexation of the luminescent Nd(3+), Eu(3+), Gd(3+), Tb(3+), Er(3+), and Yb(3+) ions by a polylysin dendrimer containing 21 amide groups in the interior and, in the periphery, 24 chromophoric dansyl units which show an intense fluorescence band in the visible region. Most of the experiments were performed in 5:1 acetonitrile/dichloromethane solution at 298 K. On addition of the lanthanide ions to dendrimer solutions, the fluorescence of the dansyl units is quenched; in Nd(3+), Er(3+), and Yb(3+), a sensitized near-infrared emission of the lanthanide ion is observed. At low metal ion concentrations, each dendrimer hosts only one metal ion and when the hosted metal ion is Nd(3+) or Eu(3+), the fluorescence of all the 24 dansyl units of the dendrimer is quenched with unitary efficiency. Quantitative measurements were performed in a variety of experimental conditions, including protonation of the dansyl units and measurements in rigid matrix at 77 K where a sensitized Eu(3+) emission could also be observed. The results obtained have been interpreted on the basis of the energy levels and redox potentials of dendrimer and metal ions.     

Azidotetrakis(diarylformamidinate)diruthenium(II,III) Compounds: Synthesis,Molecular Structures and Voltammetric Properties; Linear Free Energy Relationships in Dinuclear Compounds VII*<Superscript>,</Superscript>†

A series of Ru₂(DArF)₄(N₃) compounds have been prepared from the metathesis reaction between Ru₂(DArF)₄Cl and NaN₃, where DArF is diarylformamidinate, and aryl is X–Ph with X as 4-MeO (1), 4-Me (2), H (3), 3-MeO (4), 4-Cl (5), 3-Cl (6), 3-CF₃ (7), 4-CF₃ (8), 3,4-Cl₂ (9) and 3,5-Cl₂ (10). Single crystal X-ray diffraction studies of 3 and 10 revealed the expected paddlewheel motif for the first coordination sphere of Ru₂ and axial ligation of azide. Voltammetric studies revealed a (quasi)reversible oxidation (A) and a irreversible reduction (B) for all compounds, and a second (quasi)reduction (C) for compounds 6–10. The half-wave potentials of couple A span a remarkable range of 640 mV, and they correlate linearly with the Hammett constant (σ) of the aryl substituent.¹Dedicated to Professor F. Al Cotton, mentor, friend, and pioneer, on the occasion of his 75th birthday. ²For part VI, see C. Lin, T. Ren, E.J. Valente, and J.D. Zubkowski (1999). J. Organomet. Chem. 579, 114.     

Molecular motions and the structure ofβ-cyclodextrin inclusion complexes with ferrocene, [3]-ferrocenophane-1,3-dione and ruthenocene

Spin-lattice relaxation time measurements in laboratory and rotating frames as well as proton second moment analysis have been used to investigate molecular motions in -cyclodextrin (CD) and its solid inclusion complexes with the title organometallic compounds. Different dynamical processes have been identified in the host lattice along with high mobility of the ferrocene and ruthenocene guest molecules. The Arrhenius parameters of all motions were obtained. The assumption based on the second moment measurements was made about the axial structure of the ferrocene complex and the equatorial one of the ruthenocene complex at low temperatures. The bridged ferrocenophane molecule was shown to be rigid on the NMR time scale. The ternary inclusion complex of -CD with ruthenocene and iodine was also studied and no evidence of redox reactions was observed.     

Liquid chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry of the Alternaria mycotoxins alternariol and alternariol monomethyl ether in fruit juices and beverages

Alternariol (AOH) and alternariol monomethyl ether (AME) are among the main mycotoxins formed in apples and other fruits infected by Alternaria alternata. For determination of AOH and AME by LC, apple juice and other fruit beverages were cleaned up on C18 and aminopropyl solid-phase extraction columns. Positive and negative ion mass spectra of AOH and AME under electrospray (ESI) and atmospheric pressure chemical ionization (APCI) conditions were obtained. Collision-induced dissociation of the [M+H]+ and [M-H]- ions for both compounds were also studied. The phenolic anions of both compounds are more stable with less fragmentation. In quantitative analysis, negative ion detection also offers lower background and better sensitivity. Sensitive LC-MS and LC-MS-MS confirmatory procedures based on APCI with negative ion detection were applied to confirm the natural occurrence of AOH in nine samples of apple juice and in single samples of some other clear fruit beverages--grape juice, cranberry nectar, raspberry juice, red wine, and prune nectar (which also contained 1.4 ng AME/ml)--at levels of up to 6 ng AOH/ml. Electrospray LC-MS-MS with negative ion detection and in multiple reaction monitoring mode offers higher sensitivity and specificity. Absolute detection was better than 4 pg per injection for both compounds.     

Preparation and structural characterization of polymer-supported methylrhenium trioxide systems as efficient and selective catalysts for the epoxidation of olefins

Novel heterogeneous compounds of methylrhenium trioxide (MTO) were prepared with poly(4-vinylpyridine) and polystyrene as polymeric supports. The wide-angle X-ray diffraction (WAXS.) analysis, performed by the application of the difference method, showed, in a representative case of the poly(4-vinylpyridine)/MTO derivatives, a slightly distorted octahedral conformation on the metal's primary coordination sphere. The Re-O and Re-C bond distances were not influenced by the polymeric nature of the ligand, while the Re-N bond distance was abnormally shorter than those previously observed for homogeneous MTO/L(n) complexes, showing a strong coordination of the rhenium atom to the support. A set of scanning electron microscopy (SEM) photographs showing the morphology of the surface of particles of poly(4-vinylpyridine)/MTO and polystyrene/MTO systems are reported. The reticulation grade of the polymer was a crucial factor for the morphology of the particles surface. Poly(4-vinylpyridine) 2% cross-linked systems were characterized by particles with very irregular shape and surface. Poly(4-vinylpyridine) 25% cross-linked systems showed particles with regular spherical shape, which morphology was similar to microcapsules obtained with polystyrene. All novel MTO compounds were efficient and selective heterogeneous catalysts for the epoxidation of olefins using environmentally friendly H2O2 as oxygen atom donor. The catalyst activity was maintained for at least five recycling experiments.     

Determination by the EPR Radical Equilibration Technique of the O–H Bond Dissociation Enthalpy in 3,5-Dimethylphenol

The O–H bond dissociation enthalpy (BDE) of 3,5-dimethylphenol has been determined, by using the EPR radical equilibration technique, as 362.5 ± 1.5 kJ/mol. This value is 7 kJ/mol smaller than that of phenol, this indicating that alkyl substitution of the meta hydrogens of phenol induces a weakening of the O–H bond, in contrast with what was reported in a recent calorimetric study.     

Cavitand-based nanoscale coordination cages

This communication reports design, self-assembly, solution, and solid-state characterization of nanoscale coordination cages formed by tetradentate cavitand ligands and appropriate metal precursors. The preorganization of the cavitand ligand in terms of structural rigidity and relative orientation of the pyridyl units leads to the exclusive formation of coordination cages in a wide temperature and concentration range. Desired features of the cage self-assembly process, such as reversibility in the presence of a competitive ligand and self-recognition of the cavitand components, have been assessed.