@article{MachumiYenesewMidiwoetal.2012, author = {Machumi, Francis and Yenesew, Abiy and Midiwo, Jacob O. and Heydenreich, Matthias and Kleinpeter, Erich and Tekwani, Babu L. and Khan, Shabana I. and Walker, Larry A. and Muhammad, Ilias}, title = {Antiparasitic and anticancer carvotacetone derivatives of Sphaeranthus bullatus}, series = {Natural product communications : an international journal for communications and reviews}, volume = {7}, journal = {Natural product communications : an international journal for communications and reviews}, number = {9}, publisher = {NPC}, address = {Westerville}, issn = {1934-578X}, pages = {1123 -- 1126}, year = {2012}, abstract = {The CH2Cl2-MeOH (1:1) extract of the aerial parts of Sphaeranthus bullatus, an annual herb native to tropical East Africa, showed activity against chloroquine sensitive D6 (IC50 9.7 mu g/mL) and chloroquine resistant W2 (IC50 15.0 mu g/mL) strains of Plasmodium falciparum. Seventeen secondary metabolites were isolated from the extract through conventional chromatographic techniques and identified using various spectroscopic methods. The compounds were evaluated for their in vitro antiplasmodial, antileishmanial and anticancer activities revealing activity of four carvotacetone derivatives, namely 3-acetoxy-7-hydroxy-5-tigloyloxycarvotacetone (1) 3,7-dihydroxy-5-tigloyloxycarvotacetone (2), 3-acetoxy-5,7-dihydroxycarvotacetone (3) and 3,5,7-trihydroxycarvotacetone (4); with antiplasmodial IC50 values of 1.40, 0.79, 0.60 and 3.40 mu g/mL, respectively, against chloroquine sensitive D6 strains of P. falciparum; antiplasmodial activity of IC50 2.00, 0.90, 0.68 and 2.80 mu g/mL respectively, against chloroquine resistant W2 strains of P. falciparum, antileishmanial IC50, values of 0.70, 3.00, 0.70 and 17.00 mu g/mL, respectively, against the parasite L. donovanii promastigotes, and anticancer activity against human SK-MEL, KB, BT-549 and SK-OV-3 tumor cells, with IC50 values between <1.1 - 5.3 mu g/mL, for 1-3. In addition, cytotoxic effects of the active compounds were evaluated against monkey kidney fibroblasts (VERO) and pig kidney epithelial cells (LLC-PK11). The structures of carvotacetone derivatives were determined by ID and 2D NMR spectroscopy; the absolute stereochemical configuration of 3-acetoxy-7-hydroxy-5-tigloyloxycarvotacetone (I) was determined as 3R, 4R, 5S by circular dichroism, specific rotation, H-1 NMR and 2D NMR ROESY and NOESY experiments.}, language = {en} } @article{InduliChelotiWasunaetal.2012, author = {Induli, Martha and Cheloti, Michael and Wasuna, Antonina and Wekesa, Ingrid and Wanjohi, John M. and Byamukama, Robert and Heydenrich, Matthias and Makayoto, Moses and Yenesew, Abiy}, title = {Naphthoquinones from the roots of Aloe secundiflora}, series = {Phytochemistry letters}, volume = {5}, journal = {Phytochemistry letters}, number = {3}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1874-3900}, doi = {10.1016/j.phytol.2012.04.014}, pages = {506 -- 509}, year = {2012}, abstract = {Two new naphthoquinones, 5-hydroxy-3,6-dimethoxy-2-methylnaphthalene-1,4-dione and 5,8-dihydroxy-3-methoxy-2-methylnaphthalene-1,4-dione, were isolated from the roots of Aloe secundiflora together with the known compounds chrysophanol, helminthosporin, isoxanthorin, ancistroquinone C, aloesaponarins I and II, aloesaponols I and II, laccaic acid D methyl ester and asphodelin. The structures were elucidated based on spectroscopic evidence. This appears to be the first report on the occurrence of naphthoquinones in the genus Aloe. Aloesaponarin I and 5-hydroxy-3,6-dimethoxy-2-methylnaphthalene-1,4-dione showed anti-bacterial activity against Mycobacterium tuberculosis with MIC values of 21-23 mu g/mL in the Microplate Alamar Blue Assay (MABA) and Low Oxygen Recovery Assay (LORA); 5-hydroxy-3,6-dimethoxy-2-methylnaphthalene-1,4-dione also showed cytotoxicity against the Vero cell line (IC50 = 10.2 mu g/mL).}, language = {en} } @article{GumulaHeydenreichDereseetal.2012, author = {Gumula, Ivan and Heydenreich, Matthias and Derese, Solomon and Ndiege, Isaiah O. and Yenesew, Abiy}, title = {Four isoflavanones from the stem bark of Platycelphium voense}, series = {Phytochemistry letters}, volume = {5}, journal = {Phytochemistry letters}, number = {1}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1874-3900}, doi = {10.1016/j.phytol.2011.11.012}, pages = {150 -- 154}, year = {2012}, abstract = {From the stem bark of Platycelphium voense (Leguminosae) four new isoflavanones were isolated and characterized as (S)-5,7-dihydroxy-2 ',4 '-dimethoxy-3 '-(3 ''-methylbut-2 ''-enyl)-isoflavanone (trivial name platyisoflavanone A), (+)-5,7,2 '-trihydroxy-4 '-methoxy-3 '-(3 ''-methylbut-2 ''-enyl)-isoflavanone (platyisoflavanone B), 5,7-dihydroxy-4 '-methoxy-2 ''-(2 '''-hydroxyisopropyl)-dihydrofurano-[4 '',5 '':3 ',2 ']-isoflavanone (platyisoflavanone C) and 5,7,2 ',3 ''-tetrahydroxy-2 '',2 ''-dimethyldihydropyrano-[5 '',6 '':3 ',4 ']-isoflavanone (platyisoflavanone D). In addition, the known isoflavanones, sophoraisoflavanone A and glyasperin F; the isoflavone, formononetin; two flavones, kumatakenin and isokaempferide; as well as two triterpenes, betulin and beta-amyrin were identified. The structures were elucidated on the basis of spectroscopic evidence. Platyisoflavanone A showed antibacterial activity against Mycobacterium tuberculosis in the microplate alamar blue assay (MABA) with MIC = 23.7 mu M, but also showed cytotoxicity (IC50 = 21.1 mu M) in the vero cell test.}, language = {en} } @article{MunzkeSaundersOmranietal.2012, author = {Munzke, Dorit and Saunders, John and Omrani, Hengameh and Reich, Oliver and Loock, Hans-Peter}, title = {Modeling of fiber-optic fluorescence probes for strongly absorbing samples}, series = {Applied optics}, volume = {51}, journal = {Applied optics}, number = {26}, publisher = {Optical Society of America}, address = {Washington}, issn = {1559-128X}, doi = {10.1364/AO.51.006343}, pages = {6343 -- 6351}, year = {2012}, abstract = {The dynamic range of fiber-optic fluorescent probes such as single fibers and fiber bundles is calculated for strongly absorbing samples, such as process liquids, foodstuffs, and lubricants. The model assumes an excitation beam profile based on a Lambertian light source and uses analytical forms of the collection efficiency, followed by an Abel transformation and numerical integration. It is found that the effect of primary absorption of the excitation light and secondary absorption of the fluorescence is profound. For fiber bundles and bifurcated fiber probes, the upper accessible concentration limit is roughly given by the absorption length of the primary and secondary absorption. Fluorescence detectors that are placed at right angles to the excitation beam axis or collinear to the beam axis are equally strongly affected by secondary absorption. A probe in which the same fiber is used for excitation and for collection of the fluorescence emerges as the fiber probe with the largest accessible concentration range.}, language = {en} } @article{RuizHassReich2012, author = {Ruiz, Salome Vargas and Hass, Roland and Reich, Oliver}, title = {Optical monitoring of milk fat phase transition within homogenized fresh milk by Photon Density Wave spectroscopy}, series = {International dairy journal}, volume = {26}, journal = {International dairy journal}, number = {2}, publisher = {Elsevier}, address = {Oxford}, issn = {0958-6946}, doi = {10.1016/j.idairyj.2012.03.012}, pages = {120 -- 126}, year = {2012}, abstract = {Photon Density Wave (PDW) spectroscopy was applied for temperature dependent monitoring of melting and crystallization of milk fat within homogenized fresh milk. As an in-line process analytical technique, PDW spectroscopy quantifies continuously the optical properties of turbid material, providing an insight into its structural processes. Here, the measured absorption coefficients reflect temperature as well as fat content of milk and the reduced scattering coefficients probe physical changes of the light scattering fat droplets and casein micelles. Thermal processing reveals breakpoints within the temperature trend of the reduced scattering coefficient of fat containing milk. Found at 16 degrees C and 24 degrees C while cooling and heating, respectively, they are associated to the phase transitions of milk fat. Continuous isothermal measurement of the optical coefficients showed that the crystallization process requires several hours. The strongly changing reduced scattering coefficient implies that the thermal history of milk will have a major impact on any method based on light scattering as quantitative analytical technique.}, language = {en} } @article{WoehlBruhnBadarBertzetal.2012, author = {W{\"o}hl-Bruhn, Stefanie and Badar, Muhammad and Bertz, Andreas and Tiersch, Brigitte and Koetz, Joachim and Menzel, Henning and M{\"u}ller, Peter P. and Bunjes, Heike}, title = {Comparison of in vitro and in vivo protein release from hydrogel systems}, series = {Journal of controlled release}, volume = {162}, journal = {Journal of controlled release}, number = {1}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0168-3659}, doi = {10.1016/j.jconrel.2012.05.049}, pages = {127 -- 133}, year = {2012}, abstract = {Hydrogel systems based on hydroxyethyl starch-polyethylene glycol methacrylate (HES-P(EG)(6)MA) or hydroxyethyl starch methacrylate (HES-MA) were used to assess the protein release behavior. Here, we analyzed the in vitro release of FITC-anti-human antibodies incorporated in either HES-P(EG)(6)MA or HES-MA hydrogel delivery systems in PBS or human serum. In addition, hydrogel disks and microparticles prepared from the two polymers were subcutaneously implanted in BALB/c mice. The in vivo release of FITC-IgG was non-invasively monitored by an in vivo imaging system (IVIS 200) over a time period of up to 3 months. The imaging system allowed to asses individual animals over time, therefore only a small number of animals was required to obtain high quality data. The reduction in fluorescence intensity at the site of administration was compared to in vitro release profiles. These investigations demonstrated a sustained release from HES-MA hydrogel disks compared to rapidly degrading HES-P(EG)(6)MA disks and microparticles. The sustained release from HES-MA disks could be further optimized by using increased polymer concentrations. Human serum as in vitro release medium reflected better the in vivo release from HES-P(EG)(6)MA systems than PBS, suggesting that the presence of organic substances like proteins or lipids may play a significant role for the release kinetics.}, language = {en} } @article{KoethTierschAppelhansetal.2012, author = {Koeth, Anja and Tiersch, Brigitte and Appelhans, Dietmar and Gradzielski, Michael and C{\"o}lfen, Helmut and Koetz, Joachim}, title = {Synthesis of Core-Shell Gold Nanoparticles with Maltose-Modified Poly(Ethyleneimine)}, series = {Journal of dispersion science and technology}, volume = {33}, journal = {Journal of dispersion science and technology}, number = {1-3}, publisher = {Taylor \& Francis Group}, address = {Philadelphia}, issn = {0193-2691}, doi = {10.1080/01932691.2010.530084}, pages = {52 -- 60}, year = {2012}, abstract = {The synthesis of ultrafine gold nanoparticles in presence of maltose-modified hyperbranched poly(ethyleneimines) (PEI) is described. The polymer acted as both a reducing and stabilising agent in the particle formation process. The nanoparticles were characterized by means of dynamic light scattering (DLS), transmission electron microscopy (TEM), analytical ultracentrifugation (AUC), small-angle x-ray scattering (SAXS), and small-angle neutron scattering (SANS). The mechanism of nanoparticle formation can be described in two steps. The reduction process of the Au3+ ions located in the inner coil region of the hyperbranched PEI led to the formation of a compact gold core, and is accompanied by a collapse of the polymer coil. Therefore, in the subsequent reduction process a gold-polymer hybrid shell is formed. By using the PEI of higher molar mass, core-shell gold nanoparticles of about 3.6 nm size with a more narrow size distribution and special fluorescence behavior could be synthesized.}, language = {en} } @article{KleinpeterShainyanKirpichenkoetal.2012, author = {Kleinpeter, Erich and Shainyan, Bagrat A. and Kirpichenko, Svetlana V. and Shlykov, Sergei A.}, title = {Structure and Conformational Properties of 1,3,3-Trimethyl-1,3-Azasilinane : Gas Electron Diffraction, Dynamic NMR, and Theoretical Study.}, issn = {1089-5639}, year = {2012}, language = {en} } @phdthesis{Mucic2012, author = {Mucic, Nenad}, title = {Thermodynamics, kinetics and rheology of surfactant adsorption layers at water/oil interfaces}, address = {Potsdam}, year = {2012}, language = {en} } @phdthesis{Bettenbuehl2012, author = {Bettenb{\"u}hl, Mario}, title = {Microsaccades: symbols in fixational eye movements}, address = {Potsdam}, pages = {117 S.}, year = {2012}, language = {en} } @phdthesis{RojasCarillo2012, author = {Rojas Carillo, Oscar Mario}, title = {Versatile uses of halogen-free Ionic Liquids for the formulation of non-aqueous microemulsion and synthesis of gold nanoparticles}, address = {Potsdam}, pages = {93, XXVI S.}, year = {2012}, language = {en} } @article{ShainyanSuslovaKleinpeter2012, author = {Shainyan, Bagrat A. and Suslova, Elena N. and Kleinpeter, Erich}, title = {Conformational analysis of 4,4-dimethyl-1-(trifluoromethylsulfonyl)-1,4-azasilinane and 2,2,6,6-tetramethyl-4- (trifluoromethylsulfonyl)-1,4,2,6-oxazadisilinane}, year = {2012}, abstract = {4,4-Dimethyl-1-(trifluoromethylsulfonyl)-1,4-azasilinane 1 and 2,2,6,6-tetramethyl-4-(trifluoromethylsulfonyl)- 1,4,2,6-oxazadisilinane 2 were studied by variable temperature dynamic 1H, 13C, 19F NMR spectroscopy and theoretical calculations at the DFT (density functional theory) and MP2 (Moller-Plesset 2) levels of theory. Both kinetic (barriers to ring inversion) and thermodynamic data (frozen conformational equilibria) could be obtained for the two compounds. The computations revealed two minima on the potential energy surface for molecules 1 and 2 corresponding to the rotamers with the CF3SO2 group directed inward and outward the ring, the latter being 0.20.4 kcal/mol (for 1) and 1.1 kcal/mol (for 2) more stable than the former. The vibrational calculations at the DFT and MP2 levels of theory give the values of the free energy difference Delta G degrees for the 'inward' reversible arrow 'outward' equilibrium consistent with those determined from the experimentally measured ratio of the rotamers. The structure of crystalline compound 2 was ascertained by X-ray diffraction analysis.}, language = {en} } @article{LazarevaAlbanovShainyanetal.2012, author = {Lazareva, Nataliya F. and Albanov, Alexander I. and Shainyan, Bagrat A. and Kleinpeter, Erich}, title = {Synthesis and conformational properties of substituted 1,4,2-oxazasilinanes: low temperature NMR study and quantum chemical calculations}, doi = {10.1016/j.tet.2011.11.077}, year = {2012}, language = {en} } @article{KleinpeterStojanovicMarkovicetal.2012, author = {Kleinpeter, Erich and Stojanovic, Milovan and Markovic, Rade and Baranac-Stojanovic, Marija}, title = {Synthesis of thiazolidine-fused heterocycles via exo-mode cyclizations of vinylogous N-acyliminium ions}, issn = {1477-0520}, year = {2012}, abstract = {Syntheses of thiazolidine-fused heterocycles via exo-mode cyclizations of vinylogous N-acyliminium ions incorporating heteroatom-based nucleophiles have been examined and discussed. The formation of (5,6)-membered systems was feasible with all nucleophiles tried (O, S and N), while the closing of the five-membered ring was restricted to O- and S-nucleophiles. The closure of a four-membered ring failed. Instead, the bicyclic (5,6)-membered acetal derivative and the tricyclic system with an eight-membered central ring were obtained from the substrates containing O and S nucleophilic moieties, respectively. The reaction outcome and stereochemistry are rationalized using quantum chemical calculations at B3LYP/6-31G(d) level. The exclusive cis-stereoselectivity in the formation of (5,6)- and (5,5)-membered systems results from thermodynamic control, whereas the formation of the eight-membered ring was kinetically controlled.}, language = {en} } @article{ShainyanKleinpeter2012, author = {Shainyan, Bagrat A. and Kleinpeter, Erich}, title = {Conformational preferences of Si-Ph,H and Si-Ph,Me silacyclohexanes and 1,3-thiasilacyclohexanes : Additivity of conformational energies in 1,1-disubstituted heterocyclohexanes}, issn = {0040-4020}, year = {2012}, abstract = {The conformational equilibria of 1-phenyl-1-silacyclohexane 1, 3-phenyl-1,3-thiasilacyclohexane 2, 1-methyl-1- phenyl-1-silacyclohexane 3, and 3-methyl-3-phenyl-1,3-thiasilacyclohexane 4 have been studied for the first time by low temperature C-13 NMR spectroscopy at 103 K. Predominance of the equatorial conformer of compound 1 (Ph-eq/Ph-ax=78\%:22\%) is much less than in its carbon analog, phenylcyclohexane (nearly 100\% of Ph-eq). And in contrast to 1-methyl-1- phenylcyclohexane, the conformers with the equatorial Ph group are predominant for compounds 3 and 4: at 103 K, Ph-eq/Ph- ax ratios are 63\%:37\% (3) and 68\%:32\% (4). As the Si-C bonds are elongated with respect to C-C bonds, the barriers to ring inversion are only between 5.2-6.0 (ax -> eq) and 5.4-6.0 (eq -> ax) kcal mol(-1). Parallel calculations at the DFT and MP2 level of theory (as well as the G2 calculations for compound 1) show qualitative agreement with the experiment. The additivity/nonadditivity of conformational energies of substituents on cyclohexane and silacyclohexane derivatives is analyzed. The geminally disubstituted cyclohexanes containing a phenyl group show large deviations from additivity, whereas in 1-methyl-1-phenyl-1-silacyclohexane and 3-methyl-3-phenyl-1,3-thiasilacyclohexane the effects of the methyl and phenyl groups are almost additive. The reasons for the different conformational preferences in carbocyclic and heterocyclic compounds are analyzed using the homodesmotic reactions approach.}, language = {en} } @phdthesis{Schneider2012, author = {Schneider, Julia}, title = {Characterisation of single and multibubble cavitation through analysis of molecular, atomic and ionic line emissions}, address = {Potsdam}, pages = {117 S.}, year = {2012}, language = {en} } @phdthesis{Kupstat2012, author = {Kupstat, Annette}, title = {F{\"o}rster resonance energy transfer (FRET)-based detection of molecular binding interactions - from fundamental research to application in life science}, address = {Potsdam}, pages = {129 S.}, year = {2012}, language = {en} } @article{KleinpeterHeydenreichKochetal.2012, author = {Kleinpeter, Erich and Heydenreich, Matthias and Koch, Andreas and Linker, Torsten}, title = {Synthesis and NMR spectroscopic conformational analysis of esters of 4-hydroxy-cyclohexanone-the more polar the molecule the more stable the axial conformer}, issn = {0040-4020}, year = {2012}, abstract = {The esters of 4-hydroxy-cyclohexanone and a series of carboxylic acids R-COOH with R of different electronic and steric influence (R=Me, Et, n-Pr, i-Pr, n-Bu, i-Bu, sec-Bu, t-Bu, CF3, CH2Cl, CHCl2, CCl3, CH2Br, CHBr2, and CBr3) were synthesized and the conformational equilibria studied by 1H and 13C NMR spectroscopy at 103 K and at 295 K, respectively. The geometry of optimized structures of the axial/equatorial chair conformers was computed at the ab initio MO and DFT levels of theory. Only one preferred conformation was obtained for the axial and the equatorial conformer as well. When comparing the conformational equilibria of the cyclohexanone esters with those of the corresponding cyclohexyl esters a certain polarity contribution of the cyclohexanone framework was revealed, which is independent of the substituent effects and increases the stability of the axial conformers by a constant amount.}, language = {en} } @phdthesis{vonRuestenLange2012, author = {von R{\"u}sten-Lange, Maik}, title = {Improving Hemocompatibility of poly(ether imide) by surface functionalization with polyethers}, address = {Potsdam}, pages = {136, L S.}, year = {2012}, language = {en} } @phdthesis{Flehr2012, author = {Flehr, Roman}, title = {Design and development of novel three color-FRET systems in synthetic peptides and oligonucleotides}, address = {Potsdam}, pages = {VII, 149 S.}, year = {2012}, language = {en} } @phdthesis{Su2012, author = {Su, Fangzheng}, title = {Graphitic carbon nitride as a metal-free catalyst for photosynthesis, Amine oxidation and base-mediated reactions}, address = {Potsdam}, pages = {120 S.}, year = {2012}, language = {en} } @phdthesis{Lahn2012, author = {Lahn, Mattes}, title = {Investigation of ion concentrations in biological tissue using FLIM and 2P-microscopy}, address = {Potsdam}, pages = {94, XXVIII S.}, year = {2012}, language = {en} } @article{KleinpeterNeuvonenNeuvonenetal.2012, author = {Kleinpeter, Erich and Neuvonen, Kari and Neuvonen, Helmi and Koch, Andreas}, title = {Taft equation in the light of NBO computations : Introduction of a novel polar computational substituent constant scale for alkyl groups}, issn = {2210-271X}, year = {2012}, language = {en} } @phdthesis{Glatzel2012, author = {Glatzel, Stefan}, title = {Cellulose based transition metal nano-composites : structuring and development}, address = {Potsdam}, pages = {102, XXIII S.}, year = {2012}, language = {en} } @phdthesis{Ast2012, author = {Ast, Sandra}, title = {Integration of the 1,2,3-Triazole "Click" motif as a potent signalling element into metal ion responsive fluorescent probes for physiological cations}, address = {Potsdam}, pages = {137 S.}, year = {2012}, language = {en} } @article{KleinpeterLazarevaShainyanetal.2012, author = {Kleinpeter, Erich and Lazareva, Nataliya F. and Shainyan, Bagrat A. and Schilde, Uwe and Chipania, Nina N.}, title = {Synthesis, Molecular Structure, Conformational Analysis, and Chemical Properties of Silicon-Containing Derivatives of Quinolizidine}, issn = {0022-3263}, year = {2012}, language = {en} } @phdthesis{Junginger2012, author = {Junginger, Mathias}, title = {Interface-controlled calcium phosphate mineralization}, address = {Potsdam}, pages = {100 S.}, year = {2012}, language = {en} } @phdthesis{Xie2012, author = {Xie, Zai-Lai}, title = {Functional materials in metal-containing ionic liquids}, address = {Potsdam}, pages = {108 S.}, year = {2012}, language = {en} } @phdthesis{Luzi2012, author = {Luzi, Manja}, title = {Kinetic studies of mixed gas hydrates}, address = {Potsdam}, pages = {178, XXIII S.}, year = {2012}, language = {en} } @article{KleinpeterKoch2012, author = {Kleinpeter, Erich and Koch, Andreas}, title = {Spatial magnetic properties subject to lone pair and pi electron delocalization in benzenoid and quinoid structures : are quinoid tautomers really nonaromatic?}, issn = {1551-7004}, year = {2012}, abstract = {The spatial magnetic properties, through-space NMR shieldings (TSNMRS), of benzenoid and quinoid tautomeric structures such as benzodifurantrione and phenazine-type molecules have been calculated using the GIAO perturbation method employing the nucleus independent chemical shift (NICS) concept of Paul von Rague Schleyer and visualized as iso- chemical-shielding surfaces (ICSS) of various size and direction. The TSNMRS values were employed to quantify and visualize the partial aromaticity of the studied compounds. In the case of the surprisingly more stable quinoid tautomers, the aromaticity-synonymous with stability due to the conjugation of p electrons and lone pairs-was not found to be particularly reduced.}, language = {en} } @article{KleinpeterModarresiAlamInaloo2012, author = {Kleinpeter, Erich and Modarresi-Alam, Ali Reza and Inaloo, Iman Dindarloo}, title = {Synthesis of primary thiocarbamates by silica sulfuric acid as effective reagent under solid-state and solution conditions}, issn = {0022-2860}, year = {2012}, abstract = {A simple and efficient method for the conversion of alcohols and phenols to primary O-thiocarbamates and S- thiocarbamates in the absence of solvent (solvent-free condition) using silica sulfuric acid (SiO2OSO3H) as a solid acid is described. The products are easily distinguished by IR, NMR and X-ray data. X-ray data of the compounds reveal a planar trigonal orientation of the NH2 nitrogen atom with the partial C,N double-bond character and the CS or CO groups in synperiplanar position with CarylO and CalkylS moieties, respectively. Moreover, the OCSNH2 group which is perpendicular to the plane of the benzene ring in 1c and the central thiocarbamate SCONH2 group in 2b are essentially planar.}, language = {en} } @article{Kleinpeter2012, author = {Kleinpeter, Erich}, title = {Are lithium and sodium salts of N-(2-hydroxyphenyl)-salicylaldimine aromatic metalla-hetero[10]annulenes? An answer given by spatial magnetic properties (through space NMR shieldings-TSNMRS)}, issn = {1463-9076}, year = {2012}, abstract = {The spatial magnetic properties (through space NMR shieldings-TSNMRS) of the enol tautomer of N-(2- hydroxyphenyl)-salicylaldimine, the lithium and sodium salts in comparison with cyclodecapentaene and pyrano[2,3- b]pyrrole were studied to answer this question.}, language = {en} } @article{KleinpeterBranacStojanoviKoch2012, author = {Kleinpeter, Erich and Branac-Stojanovi, Marija and Koch, Andreas}, title = {Is the Conventional Interpretation of the Anisotropic Effects of CC Double Bonds and Aromatic Rings in NMR Spectra in Terms of the -Electron Shielding/Deshielding Contributions Correct?}, issn = {1521-3765}, year = {2012}, abstract = {Based on the nucleus-independent chemical shift (NICS) concept, isotropic magnetic shielding values have been computed along the three Cartesian axes for ethene, cyclobutadiene, benzene, naphthalene, and benzocyclobutadiene, starting from the molecular/ring center up to 10;{\AA} away. These through-space NMR spectroscopic shielding (TSNMRS) values, which reflect the anisotropic effects, have been broken down into contributions from localized- and canonical molecular orbitals (LMOs and CMOs); these contributions revealed that the proton NMR spectroscopic chemical shifts of nuclei that are spatially close to the C=C double bond or the aromatic ring should not be explained in terms of the conventionally accepted ;-electron shielding/deshielding effects. In fact, these effects followed the predictions only for the antiaromatic cyclobutadiene ring.}, language = {en} } @article{KleinpeterBalciYaparetal.2012, author = {Kleinpeter, Erich and Balci, Kubilay and Yapar, G. and Akkaya, S. and Akyuz, S. and Koch, Andreas}, title = {A conformational analysis and vibrational spectroscopic investigation on 1,2-bis(o-carboxyphenoxy) ethane molecule}, year = {2012}, abstract = {The minima on the potential energy surface of 1,2-bis(o-carboxyphenoxy) ethane (CPE) molecule in its electronic ground state were searched by a molecular dynamics simulation performed with MM2 force field. For each of the found minimum-energy conformers, the corresponding equilibrium geometry, charge distribution, HOMO-LUMO energy gap, force field, vibrational normal modes and associated IR and Raman spectral data were determined by means of the density functional theory (DFT) based electronic structure calculations carried out by using B3LYP method and various Pople- style basis sets. The obtained theoretical data confirmed the significant effects of the intra- and inter-molecular hydrogen bonding interactions on the conformational structure, force field, and group vibrations of the molecule. The same data have also revealed that two of the determined stable conformers, both of which exhibit pseudo-crown structure, are considerably more favorable in energy to the others and accordingly provide the major c ntribution to the experimental spectra of CPE. In the light of the improved vibrational spectral data obtained within the "SQM FF" methodology and "Dual Scale Factors" approach for the monomer and dimer forms of these two conformers, a reliable assignment of the fundamental bands observed in the experimental room-temperature IR and Raman spectra of the molecule was given, and the sensitivities of its group vibratb20s to conformation, substitution and dimerization were discussed.}, language = {en} } @article{KleinpeterSchainyanKirpichenko2012, author = {Kleinpeter, Erich and Schainyan, Bagrat A. and Kirpichenko, Svetlane V.}, title = {Synthesis and conformational properties of 1,3-dimethyl-3-phenyl-1,3-azasilinane : low temperature dynamic NMR and computational study}, issn = {1551-7004}, year = {2012}, abstract = {1,3-Dimethyl-3-phenyl-1,3-azasilinane was synthesized and its conformational behavior was studied by the low temperature NMR spectroscopy and quantum chemical calculations. The compound was shown to exist as an equilibrium mixture of the PhaxMeeq and PheqMeax chair conformers with the N-methyl substituent in equatorial position. The barrier to ring inversion was also determined.}, language = {en} } @article{AwadKochMickleretal.2012, author = {Awad, Duha Jawad and Koch, Andreas and Mickler, Wulfhard and Schilde, Uwe and Strauch, Peter}, title = {EPR spectroscopy of 4, 4 '-Bis(tert-butyl)-2, 2 '-bipyridine-1, 2-dithiolatocuprates(II) in host lattices with different coordination geometries}, series = {Zeitschrift f{\"u}r anorganische und allgemeine Chemie}, volume = {638}, journal = {Zeitschrift f{\"u}r anorganische und allgemeine Chemie}, number = {6}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0044-2313}, doi = {10.1002/zaac.201100517}, pages = {965 -- 975}, year = {2012}, abstract = {A series of new heteroleptic MN2S2 transition metal complexes with M = Cu2+ for EPR measurements and as diamagnetic hosts Ni2+, Zn2+, and Pd2+ were synthesized and characterized. The ligands are N2 = 4, 4'-bis(tert-butyl)-2, 2'-bipyridine (tBu2bpy) and S2 =1, 2-dithiooxalate, (dto), 1, 2-dithiosquarate, (dtsq), maleonitrile-1, 2-dithiolate, or 1, 2-dicyanoethene-1, 2-dithiolate, (mnt). The CuII complexes were studied by EPR in solution and as powders, diamagnetically diluted in the isostructural planar [NiII(tBu2bpy)(S2)] or[PdII(tBu2bpy)(S2)] as well as in tetrahedrally coordinated[ZnII(tBu2bpy)(S2)] host structures to put steric stress on the coordination geometry of the central CuN2S2 unit. The spin density contributions for different geometries calculated from experimental parameters are compared with the electronic situation in the frontier orbital, namely in the semi-occupied molecular orbital (SOMO) of the copper complex, derived from quantum chemical calculations on different levels (EHT and DFT). One of the hosts, [NiII(tBu2bpy)(mnt)], is characterized by X-ray structure analysis to prove the coordination geometry. The complex crystallizes in a square-planar coordination mode in the monoclinic space group P21/a with Z = 4 and the unit cell parameters a = 10.4508(10) angstrom, b = 18.266(2) angstrom, c = 12.6566(12) angstrom, beta = 112.095(7)degrees. Oxidation and reductions potentials of one of the host complexes, [Ni(tBu2bpy)(mnt)], were obtained by cyclovoltammetric measurements.}, language = {en} } @article{PrimusKumke2012, author = {Primus, Philipp-A. and Kumke, Michael Uwe}, title = {Flash photolysis study of complexes between salicylic acid and lanthanide ions in water}, series = {The journal of physical chemistry : A, Molecules, spectroscopy, kinetics, environment \& general theory}, volume = {116}, journal = {The journal of physical chemistry : A, Molecules, spectroscopy, kinetics, environment \& general theory}, number = {4}, publisher = {American Chemical Society}, address = {Washington}, issn = {1089-5639}, doi = {10.1021/jp2043575}, pages = {1176 -- 1182}, year = {2012}, abstract = {In the natural environment humic substances (HS) represent a major factor determining the speciation of metal ions, e.g., in the context of radionuclide migration. Here, due to their intrinsic sensitivity and selectivity, spectroscopic methods are often applied, requiring a fundamental understanding of the photophysical processes present in such HS-metal complexes. Complexes with different metal ions were studied using 2-hydroxybenzoic acid (2HB) as a model compound representing an important part of the chelating substructures in HS. In flash photolysis experiments under direct excitation of 2HB in the absence and the presence of different lanthanide ions, the generation and the decay of the 2HB triplet state, of the phenoxy radical, and of the solvated electron were monitored. Depending on the lanthanide ion different intracomplex processes were observed for these transient species including energy migration to and photoreduction of the lanthanide ion. The complexity of the intracomplex photophysical processes even for small molecules such as 2HB underlines the necessity to step-by-step approach the photochemical reactivity of HS by using suitable model compounds.}, language = {en} } @article{ShainyanTolstikovaSchilde2012, author = {Shainyan, Bagrat A. and Tolstikova, Ljudmila L. and Schilde, Uwe}, title = {Simple methods for the preparation of N-triflyl guanidines and the structure of compounds with the CF3SO2N=C-N fragment}, series = {Journal of fluorine chemistry}, volume = {135}, journal = {Journal of fluorine chemistry}, number = {1}, publisher = {Elsevier}, address = {Lausanne}, issn = {0022-1139}, doi = {10.1016/j.fluchem.2011.12.004}, pages = {261 -- 264}, year = {2012}, abstract = {Two novel and simple approaches to N-triflyl guanidines are elaborated. Owing to very strong conjugation the formally double C=N bond of TIN=C(NHR)(2) is longer than the formally single N-C bonds. Energetic effect of the triflylgroup on the conjugation in the N-C=N moiety is estimated to be >= 150 kcal/mol.}, language = {en} } @article{KleinpeterHeydenreichKochetal.2012, author = {Kleinpeter, Erich and Heydenreich, Matthias and Koch, Andreas and Linker, Torsten}, title = {Synthesis and NMR spectroscopic conformational analysis of esters of 4-hydroxy-cyclohexanone-the more polar the molecule the more stable the axial conformer}, series = {Tetrahedron}, volume = {68}, journal = {Tetrahedron}, number = {10}, publisher = {Elsevier}, address = {Oxford}, issn = {0040-4020}, doi = {10.1016/j.tet.2012.01.022}, pages = {2363 -- 2373}, year = {2012}, abstract = {The esters of 4-hydroxy-cyclohexanone and a series of carboxylic acids R-COOH with R of different electronic and steric influence (R=Me, Et, n-Pr, i-Pr, n-Bu, i-Bu, sec-Bu, t-Bu, CF3, CH2Cl, CHCl2, CCl3, CH2Br, CHBr2, and CBr3) were synthesized and the conformational equilibria studied by H-1 and C-13 NMR spectroscopy at 103 K and at 295 K, respectively. The geometry of optimized structures of the axial 'equatorial chair conformers was computed at the ab initio MO and DFT levels of theory. Only one preferred conformation was obtained for the axial and the equatorial conformer as well. When comparing the conformational equilibria of the cyclohexanone esters with those of the corresponding cyclohexyl esters a certain polarity contribution of the cyclohexanone framework was revealed, which is independent of the substituent effects and increases the stability of the axial conformers by a constant amount.}, language = {en} } @article{SetoMaDavisetal.2012, author = {Seto, Jong and Ma, Yurong and Davis, Sean A. and Meldrum, Fiona and Gourrier, Aurelien and Kim, Yi-Yeoun and Schilde, Uwe and Sztucki, Michael and Burghammer, Manfred and Maltsev, Sergey and J{\"a}ger, Christian and C{\"o}lfen, Helmut}, title = {Structure-property relationships of a biological mesocrystal in the adult sea urchin spine}, series = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {109}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, number = {10}, publisher = {National Acad. of Sciences}, address = {Washington}, issn = {0027-8424}, doi = {10.1073/pnas.1109243109}, pages = {3699 -- 3704}, year = {2012}, abstract = {Structuring overmany length scales is a design strategy widely used in Nature to create materials with unique functional properties. We here present a comprehensive analysis of an adult sea urchin spine, and in revealing a complex, hierarchical structure, showhow Nature fabricates a material which diffracts as a single crystal of calcite and yet fractures as a glassy material. Each spine comprises a highly oriented array of Mg-calcite nanocrystals in which amorphous regions and macromolecules are embedded. It is postulated that this mesocrystalline structure forms via the crystallization of a dense array of amorphous calcium carbonate (ACC) precursor particles. A residual surface layer of ACC and/or macromolecules remains around the nanoparticle units which creates the mesocrystal structure and contributes to the conchoidal fracture behavior. Nature's demonstration of howcrystallization of an amorphous precursor phase can create a crystalline material with remarkable properties therefore provides inspiration for a novel approach to the design and synthesis of synthetic composite materials.}, language = {en} } @article{SchmidtKrehlKellingetal.2012, author = {Schmidt, Bernd and Krehl, Stefan and Kelling, Alexandra and Schilde, Uwe}, title = {Synthesis of 8-Aryl-Substituted Coumarins based on Ring-Closing Metathesis and Suzuki-Miyaura coupling - synthesis of a Furyl Coumarin natural product from Galipea panamensis}, series = {The journal of organic chemistry}, volume = {77}, journal = {The journal of organic chemistry}, number = {5}, publisher = {American Chemical Society}, address = {Washington}, issn = {0022-3263}, doi = {10.1021/jo2026564}, pages = {2360 -- 2367}, year = {2012}, abstract = {The synthesis of 7-methoxy-8-(4-methyl-3-furyl)-2H-chromen-2-one, a natural product with antileishmanial activity recently isolated from the plant Galipea panamensis, is described. The key step is a Suzuki-Miyaura coupling of a furan-3-boronic acid and an 8-halocoumarin, which is advantageously synthesized using a ring-closing metathesis reaction. Several non-natural analogues are also available along these lines.}, language = {en} } @article{LazarevaShainyanSchildeetal.2012, author = {Lazareva, Nataliya F. and Shainyan, Bagrat A. and Schilde, Uwe and Chipanina, Nina N. and Oznobikhina, Larisa P. and Albanov, Alexander I. and Kleinpeter, Erich}, title = {Synthesis, molecular structure, conformational analysis, and chemical properties of silicon-containing derivatives of quinolizidine}, series = {The journal of organic chemistry}, volume = {77}, journal = {The journal of organic chemistry}, number = {5}, publisher = {American Chemical Society}, address = {Washington}, issn = {0022-3263}, doi = {10.1021/jo202658n}, pages = {2382 -- 2388}, year = {2012}, abstract = {A silicon analog of quinolizidine 3,3,7,7-tetramethylhexahydro-1H-[1,4,2]oxazasilino[4,5-d][1,4,2]oxazasilin-9a-yl)methanol 3 was synthesized. X-ray diffraction analysis confirmed the trans configuration and low temperature NMR spectroscopy both the flexibility (barrier of interconversion 5.8 kcal mol(-1)) and the conformational equilibrium (chair-chair and chair-twist conformers) of the compound. The relative stability of the different isomers/conformers of 3 was calculated also at the MP2/6-311G(d,p) level of theory. Intra- and intermolecular hydrogen bonding in 3 and the appropriate equilibrium between free and self-associated molecules was studied in solvents of different polarity. Both the N-methyl quaternary ammonium salt and the O-trimethylsilyl derivative of 3 could be obtained and their structure determined.}, language = {en} } @article{KreyeTueruencSehlingeretal.2012, author = {Kreye, Oliver and T{\"u}r{\"u}nc, Oguz and Sehlinger, Ansgar and Rackwitz, Jenny and Meier, Michael A. R.}, title = {Structurally diverse polyamides obtained from monomers derived via the Ugi multicomponent reaction}, series = {Chemistry - a European journal}, volume = {18}, journal = {Chemistry - a European journal}, number = {18}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0947-6539}, doi = {10.1002/chem.201103341}, pages = {5767 -- 5776}, year = {2012}, abstract = {The combination of the Ugi four-component reaction (Ugi-4CR) with acyclic diene metathesis (ADMET) or thiolene polymerization led to the formation of poly-1-(alkylcarbamoyl) carboxamides, a new class of substituted polyamides with amide moieties in the polymer backbone, as well as its side chains. 10-Undecenoic acid, obtained by pyrolysis of ricinoleic acid, the main fatty acid of castor oil, was used as the key renewable building block. The use of different primary amines, as well as isonitriles (isocyanides) for the described Ugi reactions provided monomers with high structural diversity. Furthermore, the possibility of versatile post-modification of functional groups in the side chains of the corresponding polymers should be of considerable interest in materials science. The obtained monomers were polymerized by ADMET, as well as thiolene, chemistry and all polymers were fully characterized. Finally, ortho-nitrobenzylamide-containing polyamides obtained by this route were shown to be photoresponsive and exhibited a dramatic change of their properties upon irradiation with light.}, language = {en} } @misc{Laschewsky2012, author = {Laschewsky, Andr{\´e}}, title = {Recent trends in the synthesis of polyelectrolytes}, series = {Current opinion in colloid \& interface science : current chemistry}, volume = {17}, journal = {Current opinion in colloid \& interface science : current chemistry}, number = {2}, publisher = {Elsevier}, address = {London}, issn = {1359-0294}, doi = {10.1016/j.cocis.2011.08.001}, pages = {56 -- 63}, year = {2012}, abstract = {Recent developments in the synthesis of polyelectrolytes are highlighted, with respect to the nature of the ionic groups, the polymer backbones, synthetic methods, and additional functionality given to the polyelectrolytes. In fact, the synthesis of new polyelectrolytes is mostly driven by material aspects, currently. The article pays particular attention to strong polyelectrolytes, and the new methods of controlled polymerization. These methods and the so-called click reactions have enabled novel designs of polyelectrolytes. Nevertheless, the polymerization of unprotected ionic monomers is still challenging and limits the synthetic possibilities. The structural aspects are complemented by considerations with respect to the aspired uses of the new polyelectrolytes.}, language = {en} } @article{ZakrevskyyRitschelDoscheetal.2012, author = {Zakrevskyy, Y. and Ritschel, T. and Dosche, C. and L{\"o}hmannsr{\"o}ben, Hans-Gerd}, title = {Quantitative calibration - and reference-free wavelength modulation spectroscopy}, series = {Infrared physics \& technology}, volume = {55}, journal = {Infrared physics \& technology}, number = {2-3}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1350-4495}, doi = {10.1016/j.infrared.2011.12.001}, pages = {183 -- 190}, year = {2012}, abstract = {A unified model for quantitative description of harmonic spectra of gases obtained by wavelength modulation spectroscopy (WMS) technique is presented. In the model, both intensity modulation (IM) and frequency modulation (FM) of the laser emission are taken into account using minimum number of parameters. For the first time, the static behavior of a laser is described as a limiting case of its dynamic response. Laser and its driver are considered as a single device converting applied bias to laser emission. This allows application of the model to any type of laser and the introduced parameters can be assigned to the corresponding laser and/or driver properties. The approach was tested using a distributed feedback (DFB) laser spectrometer. Correctness of the proposed model is justified by very good agreement between the measured and modeled/fitted spectra, which allowed evaluation of the setup performance and assessment of modulation parameters of the DFB laser. An algorithm to minimize the time of numerical calculation of harmonic spectra using numerically approximated Voigt lineshape function was developed. Absolute values of the absorption line parameters (line strength and line width) were obtained from a single calibration- and reference-free spectrum scan with accuracy better than 0.1\%.}, language = {en} } @article{KienzlerFlehrGehneetal.2012, author = {Kienzler, Andrea Altevogt Nee and Flehr, Roman and Gehne, S{\"o}ren and Kumke, Michael Uwe and Bannwarth, Willi}, title = {Verification and biophysical characterization of a New Three-Color Forster Resonance-Energy-Transfer (FRET) System in DNA}, series = {Helvetica chimica acta}, volume = {95}, journal = {Helvetica chimica acta}, number = {4}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {0018-019X}, doi = {10.1002/hlca.201100460}, pages = {543 -- 555}, year = {2012}, abstract = {We report on a new three-color FRET system consisting of three fluorescent dyes, i.e., of a carbostyril (=quinolin-2(1H)-one)-derived donor D, a (bathophenanthroline)ruthenium complex as a relay chromophore A1, and a Cy dye as A2 (FRET=Forster resonance-energy-transfer) (cf. Fig. 1). With their widely matching spectroscopic properties (cf. Fig. 2), the combination of these dyes yielded excellent FRET efficiencies. Furthermore, fluorescence lifetime measurements revealed that the long fluorescence lifetime of the Ru complex was transferred to the Cy dye offering the possibility to measure the whole system in a time-resolved mode. The FRET system was established on double-stranded DNA (cf. Fig. 3) but it should also be generally applicable to other biomolecules.}, language = {en} } @article{SchmidtKunz2012, author = {Schmidt, Bernd and Kunz, Oliver}, title = {alpha,beta-Unsaturated delta-Valerolactones through RCM-Isomerization Sequence}, series = {Synlett : accounts and rapid communications in synthetic organic chemistry}, journal = {Synlett : accounts and rapid communications in synthetic organic chemistry}, number = {6}, publisher = {Thieme}, address = {Stuttgart}, issn = {0936-5214}, doi = {10.1055/s-0031-1290488}, pages = {851 -- 854}, year = {2012}, abstract = {alpha,beta-Unsaturated d-lactones are accessible via a sequential ring-closing metathesis (RCM) double-bond migration reaction starting from butenoates of allyl alcohols. This approach proceeds efficiently with lower catalyst loadings and higher initial substrate concentrations compared to the alternative RCM of acrylates derived from homoallylic alcohols.}, language = {en} } @article{StrehmelRexhausenStrauch2012, author = {Strehmel, Veronika and Rexhausen, Hans and Strauch, Peter}, title = {New spin probes starting from 4-amino-2,2,6,6-tetramethylpiperidine-1-yloxyl}, series = {Tetrahedron letters}, volume = {53}, journal = {Tetrahedron letters}, number = {13}, publisher = {Elsevier}, address = {Oxford}, issn = {0040-4039}, doi = {10.1016/j.tetlet.2012.01.063}, pages = {1587 -- 1591}, year = {2012}, abstract = {This Letter describes four new 4-trimethylammonio-2,2,6,6-tetramethylpiperidine-1-yloxyls bearing camphorsulfonate, triflate, tosylate, or lactate as counter ions. These spin probes were made by anion metathesis of 4-trimethylammonio-2,2,6,6-tetramethylpiperidine-1-yloxyl iodide using the corresponding silver salts. The latter is made by the alkylation of 4-amino-2,2,6,6-tetramethylpiperidine-1-yloxyl. Furthermore, the Letter gives an improved synthetic way to 4-sulfonamido-2,2,6,6-tetramethylpiperidine-1-yloxyl using chlorosulfuric acid trimethylsilylester and 4-amino-2,2,6,6-tetramethylpiperidine-1-yloxyl. All the spin probes are highly interesting for the investigation of ionic liquids.}, language = {en} } @misc{KosmellaKoetz2012, author = {Kosmella, Sabine and Koetz, Joachim}, title = {Polymer-modified w/o microemulsions - with tunable droplet-droplet interactions}, series = {Current opinion in colloid \& interface science : current chemistry}, volume = {17}, journal = {Current opinion in colloid \& interface science : current chemistry}, number = {5}, publisher = {Elsevier}, address = {London}, issn = {1359-0294}, doi = {10.1016/j.cocis.2012.06.004}, pages = {261 -- 265}, year = {2012}, abstract = {Water soluble polymers can be incorporated into reverse microemulsion droplets without leaving the isotropic phase region. When the polymer is attached to the surfactant film the bending elasticity is changed, and droplet-droplet interactions are influenced. Different methods are available for studying the droplet-droplet interactions in more detail, e.g. SANS. SAXS and DLS. Conductometric measurements are very useful for detecting exchange processes between the droplets. In presence of polyampholytes a pH dependent tuning of the membrane properties becomes possible, experimentally detectable by conductometry.}, language = {en} } @article{BramborgLinker2012, author = {Bramborg, Andrea and Linker, Torsten}, title = {Regioselective synthesis of alkylarenes by two-step ipso-substitution of aromatic dicarboxylic acids}, series = {European journal of organic chemistry}, journal = {European journal of organic chemistry}, number = {28}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1434-193X}, doi = {10.1002/ejoc.201200823}, pages = {5552 -- 5563}, year = {2012}, abstract = {A strategy for the regioselective alkylation of arenes was developed, starting from commercially available and inexpensive terephthalic acid or naphthalene-1,4-dicarboxylic acid. The method entails a formal ipso-substitution of the carboxylate groups by a sequence of reductive alkylation under Birch conditions and subsequent acid-mediated rearomatization with loss of carbon monoxide and carbon dioxide. More than 20 different arenes with various side-chains were synthesized. With naphthalene-1,4-dicarboxylic acid as starting material, we were able to control the degree of alkylation by choosing the appropriate electrophile in the Birch reduction. Thus, bisalkylated naphthalenes and naphthoic acids became available chemoselectively. All reactions afforded a single regioisomer exclusively in high yields. Overall, aromatic dicarboxylic acids are suitable substrates for a two-step ipso-substitution that allows the selective synthesis of alkylated benzenes and naphthalenes.}, language = {en} }