Asymmetric Mono Research Articles

SEVERE TANGIER DISEASE WITH A NOVEL ABCA1 GENE MUTATION

Tangier disease (TD) is a rare autosomal codominant disease caused by mutations in the ATP-binding cassette transporter A1 gene ( ABCA1 ) on chromosome 9q31.1 As a consequence of impaired ABCA1 function, cholesterol accumulates in macrophages and other cells of the reticulo-endothelial system,2 leading to hepatosplenomegaly, lymphadenopathy, and enlarged yellow tonsils. Almost complete absence of high-density lipoprotein cholesterol (HDL) and low or absent levels of apolipoprotein A-I (apoA-I) are characteristic. Neurologically, patients with TD often have a peripheral neuropathy. Relapsing and remitting asymmetric mono- or polyneuropathy and slowly progressive distal symmetric polyneuropathy are more frequent than a severe syringomyelia-like subtype.3 Mutations in the ABCA1 gene have been described in more than 10 different pedigrees. However, there is no known genotype–phenotype correlation. Here we studied the ABCA1 gene sequence together with a detailed sural nerve biopsy in a family from Afghanistan with a case of progressive syringomyelia-like phenotype and severe premature atherosclerosis. ### Methods. Methods are described in appendix e-1 on the Neurology ® Web site at www.neurology.org. #### Case report. A 49-year-old Afghan Caucasian patient presented with a 15-year history of progressive syringomyelia-like syndrome with episodes of appendicular stabbing pain. Apart from tonsillectomy at age 14 his medical history was unremarkable. Examination revealed marked …

Synthesis and structural studies of germyl and germyl/stannyl substituted tungstenocenes

One-pot reactions of [WCp2(H)2] and [WCp2(H)(SnMe3)] with "BuLi followed by an equivalent of GeMe2Cl2 afford mono(germyl) substituted tungstenocenes [WCp2(H)(GeMe2Cl)] (1) and [WCp2(SnMe3)(GeMe2Cl)] (7). Reactions of the products with tin halides in the presence NEt3 afford the mixed complexes [WCp2(SnR2X)(GeMe2Y)] (X, Y = Cl, Br, R = Me, Et), which were further converted to moderately stable compounds [WCp2(SnR2H)(GeMe2H)] (R = Me (10), Et (11)). A number of asymmetric mono(halo)-substituted germyl/stannyl tungstenocenes [WCp2(SnMe2X)(GeMe2H)] (X = Cl (12), Br (13)) and [WCp2(SnEt2Y)(GeMe2H)] (Y = Br (14), I (15)) were prepared by selective halogenation of the Sn-H bond in 10 and 11. X-Ray studies of [WCp2(H)(GeMe2Cl)] (1), [WCp2(SnEt2Br)(GeMe2Cl)] (4), and [WCp2(SnEt2Br)(GeMe2H)] (14) established classical structures of these compounds. X-Ray study of complex [WCp2(SnMeCl)(GeMe2Cl)] (3) revealed the presence of interligand Ge-Cl...Sn-Cl interactions in a highly Ge/Sn disordered structure. Analyses of molecular parameters of 1, 4, and 14 suggest the presence of a negative hyperconjugation between metal lone pairs and the sigma*-orbital of the E-X bond, which is stronger in bromo substituted complexes in comparison with chloro substituted ones.

Supramolecular Architectures of C 3 -Symmetrical and Asymmetrical Discotics

Chiral ( 3b ) and achiral ( 3a ) C 3 -symmetrical nitrogen centered amide disks were investigated with optical polarizing microscopy, differential scanning calorimetry and UV-Vis/circular dichroism spectroscopy. Similar to the carbonyl centered amide disks 1a / b , only achiral compound 3a shows order in the liquid crystalline phase. Using the same techniques, two asymmetrical mono amide bisurea disks were investigated, one containing 6 "chiral urea" groups ( 4 ) and the other containing 3 "chiral amide" centers ( 5 ). These compounds do show supramolecular aggregation in dilute apolar solutions, featuring hysteresis in experiments investigating thermoreversibility; similar to C 3 -symmetrical trisurea compounds 2a / b .

Preparation and Reactions of 2,2-Dimethyl-1,3-dioxan-5-one-SAMP-Hydrazone: A Versatile Chiral Dihydroxyacetone Equivalent

The SAMP-hydrazone of 2,2-dimethyl-1,3-dioxan-5-one represents a valuable chiral dihydroxyacetone equivalent. Asymmetric mono- or α,α′-bisalkylations followed by auxiliary cleavage leads to the corresponding mono- or α,α′-disubstituted, acetonide protected ketodiols in excellent diastereo- and enantiomeric excesses.

Synthesis, equilibrium and NMR studies of lanthanide(III) complexes of the N-mono(methylamide) and N ′-mono(methylamide) derivatives of diethylenetriamine-N,N,N ′,N ″,N ″-pentaacetic acid†

Two derivative ligands of diethylenetriamine-N,N,N′,N′′,N′′-pentaacetic acid (H5DTPA; H5L1) were synthesized: the symmetric and asymmetric mono(methylamides) DTPA-N′-MA (H4L3) and DTPA-N-MA (H4L4). The protonation constants (log KiH) of L3 and L4 were obtained by pH-potentiometric titration: 10.04, 8.41, 2.73, 1.94 and 10.18, 6.19, 3.55, 2.0, respectively. The protonation constants and the sites of protonation were interpreted on the basis of the pH dependence of the chemical shifts of the non-labile protons. The stability constants (KLnL) of the complexes of these ligands with lanthanide(III) ions were determined by direct pH-potentiometry and competition titration. The stability constants decrease in the sequence LnL1 > LnL3 > LnL4. The log KLnL values of the complexes LnL3 and LnL4 increase with increasing atomic number of Ln3+ from La to Gd, then remain roughly unchanged up to Er and subsequently decrease slightly to Lu. The 1H and 13C NMR spectra reveal the presence of 2 isomers for the complexes LnL3 and 4 isomers for LnL4 at around 0 °C. The AB multiplets of the acetate methylene protons demonstrate the long lifetime of the Ln3+–N bonds. The coupling observed between the methyl and methylene protons of the methylamide group in the 2-D COSY spectra indicates partial double bond character of the C–NMe bond.

Studies on some new bridgehead nitrogen heterocyclic cyanine dyes

New asymmetrical mono-(tri)-methine and azomethine cyanine dyes of pyrazolo[5,4-b] quinolino [a, b]-1,4-pyra-(oxa)-zinium bromide salts were prepared. The new synthesized cyanines were identified by elemental and spectral analyses. The visible absorption spectra of some selected dyes were investigated in single and mixed solvents, and also in aqueous buffer solutions. The spectral shifts were studied in relation to molecular structure and in terms of medium effects. Molecular complex formation with DMF was verified through mixed-solvent studies.

Synthesis and solvatochromic behaviour of new asymmetrical mono-(tri)-methine cyanine dyes

6-Amino-5-cyano-3-methyl-1,4-diarylpyrano[2,3-c]pyrazole derivatives were prepared via the interaction ofα, β-unsaturated nitriles with 3-methyl-1-phenylpyrazol-5-one as starting materials in the synthesis of new asymmetrical mono-(tri)-methine cyanine dyes. The new cyanines were characterised by elemental analysis, IR and1H-NMR spectral data. The visible absorption spectra of some selected dyes were investigated in pure and mixed solvents as well as in aqueous buffer solutions.

Reactive arthritis, diagnosis and treatment: a review.

The diagnosis of reactive arthritis (ReA) is easy in typical cases with a history of an infection within 3 weeks in combination with an asymmetric mono or oligoarthritis with or without extra-articular manifestations. Subclinical microbial infections, a possible co-existing inflammatory bowel disease and the fact that in 25% of the cases the microbial agent remains unidentified, make the diagnosis more troublesome. The course of disease is usually self-remittent within 6 months but a less good long-term prognosis is pre-determined by two factors-namely, the presence of HLA-1327 and the recurrence of triggering infections. The finding of microbial fragments in the joint cavity have led to new treatment strategies especially in Chlamydia-triggered ReA. It must, however, be remembered that the antibiotics mostly used (namely, tetracyclines) also possess immunoregulatory and anticollagenolytic potential. In chronic destructive cases, antirheumatic treatment, similar to that used in rheumatoid arthritis, is recommended.

ChemInform Abstract: SYNTHESIS OF AZO COUPLED CROWN ETHERS CONTAINING TRANSITION METAL AND OTHER CHROMOPHORIC ENVIRONMENTS AND THEIR ION COMPLEXATION PROPERTIES

AbstractDer Benzokronenether (I) wird nach Nitrierung und Reduktion mit HNO2 in das Diazonium‐ . salz (II) übergeführt, dessen Azokupplung mit den Phenolen (III) die Hydroxyarylazobenzokronenether (IV) liefert.

Some aromatic derivatives of 1,4,7,10,13,16-hexaoxacyclooctadecane

Some of the derivatives of polyglycoles were obtained just by reacting the α-chlorhydrines with phenols, α-naphtol and β-naphtols in the presence of NaOH. Derivatives obtained were condensed with the ditosylates of polyethyleneglycoles in the presence of potassium tert-butoxide in THF and some asymmetrical mono and disubstituted hexaoxacyclooctadecanes were formed.

Synthesis of Azo Coupled Crown Ethers Containing Transition Metal and other Chromophoric Environments and Their Ion Complexation Properties

Abstract The crown ethers, 2,3-benzo-1,4,7,10,13-pentaoxa-cyclopentadeca-2-ene and 2,3, ll,12-dibenzo-l,4,7,10,13,16-hexaoxscyclooctadeca-2,11-diene are incorporated into H,N′-ethylenebis(acetylacetoneimino) nickel(II) and copper(II), phenol, and β-naphthol by diazo coupling reactions. The selective nature of the coupling reaction has-been demonstrated by the isolation of both asymmetric mono- and symmetric bis(glyoxalarylcrownhydrazoneimino) metal(II) complexes. An interesting binuclear complex containing two intramolecularly rearranged (glyoxal-hydrazonearylimino) metal(II) groups joined by 18-crown-6 result8 when bis(arenediazonium)-18-crown-6 is coupled with the metal(I1) Schiff bases. The substituted ethers form cationic salts with NaClO4, KCNS, NH4CNS, 14g(CNS)2 and Ca(CNS)2. All the synthesised ethers exhibit ion selectivity sequence as K+ > Na+ and Ca2+ > Mg2+.

ChemInform Abstract: DIAZO COUPLING REACTIONS OF COORDINATED LIGANDS ‐ NICKEL(II) COMPLEXES OF SUBSTITUTED GLYOXALARYLHYDRAZONEIMINES

AbstractAus den entsprechenden Nickelkomplexen entstehen mit Diazoniumsalzen Di‐ und Monosubstitutionsprodukte (I) bzw. (II).

Diazo Coupling Reactions of Coordinated Ligands-Nickel(II) Complexes of Substituted Glyoxalarylhydrazoneimines

Abstract Diazo coupling reactions of nickel (II) complexes of 4, 9-dimethyl-5, 8-diazadodeca-4, 8-diene-2, 11-dione and 4, 6, 9-trimethy1-5, 8-diazadodeca-4, 8-diene-2,11-dione in aqueous methanol have been studied. It is shown that the diazo coupling reaction proceeds selectively leading to asymmetric mono(glyoxalarylhydra-zoneimino) nickel (II) and symmetric bie (glyoxalaryl-hydrazoneimino) nickel (II) complexes. Synthesis of these types of complexes has been achieved by direct synthesis from diazo coupled Schiff bases derived from β-diketones and 1,2 diamines and nickel (II) acetate. The products are characterised by elemental analysis, spectroscopic methods, conductivity studies and magnetic susceptibility measurements.