Synthesis of 3-(4-heteroaryl-phenyl)-8-oxabicyclo[3.2.1]octane-2-carboxylic acid methyl esters

Cross coupling protocols were applied for the synthesis of 3-(4-heteroaryl-phenyl)-8-oxabicyclo[3.2.1]oct-2-ene-2-carboxylic acid methyl esters. Stille conditions produced the corresponding products in reasonable yields. Samarium iodide reduction of the resulting coupling products produced the 2β-carbomethoxy-3α-aryl-8-oxabicyclo[3.2.1]octane diastereoisomers as the major, and the 2β-carbomethoxy-3β-aryl-8-oxabicyclo[3.2.1]octane diastereoisomer as the minor products. Both diastereomers manifested inhibition of the dopamine (DAT) and serotonin (SERT) transporters, with some selectivity for SERT inhibition.     

On the π coordination of organometallic fullerene complexes

Novel organometallic complexes of fullerene C?? and aryl ligands were simulated. The nature and characteristics of this family of complexes involving π coordination between the fullerene and a metal centre have been studied from a theoretical point of view. We are particularly interested in complexes where η? coordination is present, this being the strangest manifestation of known coordinations, and thus we have studied several known and simulated compounds of this kind in order to understand the lack of examples. The presence of other η? or η? ligands on the opposite side seems to be an important element aiding the stabilization of these complexes, also inducing the conductive and semiconductive behaviour of the studied species.     

New practical synthesis of 5‐formylindole

5‐Formylindole ( 2 ) was synthesized in good overall yield starting from 3‐methyl‐4‐nitrobenzaldehyde ( 4 ) by utilization of the Batcho‐Leimgruber indole synthesis.     

Oxone as oxygen donor in the catalytic hydroxylation of saturated hydrocarbons

Manganese porphyrin complexes catalyze the hydroxylation of saturated hydrocarbons by potassium hydrogen persulfate (or Oxone) at room temperature. High conversions of hydrocarbons are obtained.     

Preparation of a new chiral acridino-18-crown-6 ether-based stationary phase for enantioseparation of racemic protonated primary aralkyl amines

Starting from commercially available and relatively cheap chemicals first enantiopure dimethyl-substituted monoaza-18-crown-6 ether (R,R)-21 containing a diphenylamine unit was prepared, which was then transformed to dimethyl-substituted acridino-18-crown-6 ligand (R,R)-19 having an N-allyl-carbamoyl linker by several steps. The terminal double bond of the latter made possible to attach (R,R)-19 to γ-mercaptopropyl-functionalized spherical HPLC quality silica gel obtaining a new chiral stationary phase (R,R)-CSP-37. Based on electronic circular dichroism (ECD) studies the N-allyl-carbamoyl group attached to the acridine ring of the chiral host (R,R)-19 does weaken exciton interaction between the host and guest molecules, but does not destroy the discriminating power of the chiral host. An HPLC column filled with (R,R)-CSP-37 was tested for the enantioseparation of racemic 1-(1-naphthyl)- and 1-(2-naphthyl)ethylamine hydrogenperchlorates using isocratic conditions.     

Shortcuts in Cosmological Branes

We aim at gathering information from gravitational interaction in the Universe, at energies where quantum gravity is required. In such a setup a dynamical membrane world in a space-time with scalar bulk matter described by domain walls, as well as a dynamical membrane world in empty Anti de Sitter space-time, is analyzed. We later investigate the possibility of having shortcuts for gravitons leaving the membrane and returning subsequently. In comparison with photons following a geodesic inside the brane, we verify that shortcuts exist. For late time universes they are small, but for some primordial universes they can be quite effective. In the case of matter branes, we argue that at times just before nucleosynthesis the effect is sufficiently large to provide corrections to the inflationary scenario, especially as concerning the horizon problem and the Cosmological Background Radiation.     

Untersuchungen über die regionale Kationenverteilung im menschlichen Gehirn

Zusammenfassung Es wird eine verbesserte Gehirnpräparation durch Verwendung einer Formalinatmosphäre beschrieben. Die Excision der Gehirnzentren wird mit Glas- oder Platingeräten durchgeführt, um Fremdioneneinschleppung hintanzuhalten. Auf einem Platinnetzchen mit Kapillardrähten erfolgt der Aufschluß und das Auftragen der mineralisierten Probe auf das Chromatographie-Papier.In einigen Thalamusproben gelang der eindeutige tüpfelanalytische Nachweis von Silber.Die Elemente Eisen und Kupfer wurden polarographisch bestimmt; die erhaltenen sehr unterschiedlichen Werte weisen auf spezielle Funktionen dieser Ionen hin.Vermutlich üben Spurenelemente eine spezifische Kationenwirkung in Spezialzellen aus.Mit Hilfe der beschriebenen Methodik können Fragen der Topochemie der Kationen des Gehirnes geklärt werden.Mit 1 AbbildungHerrn Prof. Dr.O. Kratky zum 60. Geburtstag gewidmet.     

Synthesis of new optically active acridino-18-crown-6 ligands and studies of their potentiometric selectivity toward the enantiomers of protonated 1-phenylethylamine and metal ions

Starting from commercially available and relatively inexpensive chemicals, new enantiopure diisobutyl- and dioctyl-substituted acridino-18-crown-6 ether-type ligands [(R,R)-3] and [(R,R)-4], respectively were prepared. The two lipophilic isobutyl [(R,R)-3] and octyl [(R,R)-4] groups on the stereogenic centers of these macrocycles made it possible to use them as potentiometric sensor molecules when incorporated into plasticized PVC membrane electrodes. Ligand (R,R)-3 showed appreciable enantioselectivity toward the enantiomers of 1-phenylethylammonium chloride while macrocycle (R,R)-4 exhibited a high selectivity toward the silver ion.     

Synthesis of aminomethylazetidines regioselective reactions of mesyloxymethylazetidinones with nucleophiles II

Two efficient methods have been developed for the synthesis of variously substituted 2‐aminomethylazetidine derivatives 5 by regioselective nucleophilic substitution of 4‐mesyloxymethylazetidin‐2‐ones 3 followed by reduction or by reduction of the appropriate 4‐oxo‐azetidine‐2‐carboxamides 7 . A novel ring transformation of 4‐oxoazetidine‐2‐carboxamides 7 into tetrahydroquinolines 16 by reaction with lithium aluminium hydride/aluminium trichloride has been investigated.     

Benzoxadiazocines,benzothiadiazocines and benzotriazocines-V : The synthesis of some 2-amino-6-methyl- and 2-amino-6-phenyl-5,6-dihydro-4h-3,1,6-benzothiadiazocines

A method is described for the synthesis of hydrochlorides of some type 8 title compounds in which the nucleophilicity of N-2 is reduced or completely lost so as to prevent ring contraction reactions and, as a result, making these compounds comparatively stable.