Effects of nitrogen and alkene substitution on the PtCl2 catalyzed cycloisomerization of N-tethered 1,6-enyne precursors to the triple reuptake inhibitor GSK1360707

The effects of nitrogen and alkene substitution on the cycloisomerization of N-tethered 1,6-enynes into 3-azabicyclo[4.1.0]heptene precursors to the triple reuptake inhibitor GSK1360707 are described. In general, electron donating substituents proved beneficial both in terms of the reaction rate and chemoselectivity.     

Thermal Valence Rearrangements of Heterocycles. Part 2. A new synthetic approach towards the indole ring system

A new synthetic approach towards the indole ring system is described. When dimethyl 1-methyl-2-oxa-1-aza-spiro[4.5]dec-3-ene-3,4-dicarboxylate ( 6 ) was refluxed in toluene, the previously known dimethyl 4,5,6,7-tetra-hydro-1-methyl-1H-indole-2,3-dicarboxylate ( 7 ) was obtained in 71% yield, via a 2,3-dihydroisoxazole-pyrrole rearrangement. After treatment with DDQ , the tetrahydro analogue 7 was converted to the corresponding dimethyl 1-methyl-1H-indole-2,3-dicarboxylate ( 8 ).     

Cycloalkylations of N-(ω-Halogenoalkyl)-substituted Macrocyclic Imides

With ω-halogenoalkyl isocyanates, 2-oxocyclododecane-l-carbonitrile is transformed under ring enlargement to 1-(ω-halogenoalkyl)-2,14-dioxo-1-azacyclotetradecane-3-carbonitriles. In the presence of base, these products undergo O- or C-alkylation leading to bicyclic compounds. The C-alkylation product 7 undergoes solvolysis to form a sixteen-membered ring compound.     

Erratum to “The extremal codes of length 42 with automorphism of order 7” [Discrete Math. 190 (1998) 201–213]

This note corrects a mistake in the previous paper where some of the codes are missing and others are repeated. All [42, 21, 8] binary self-dual with an automorphism of order 7 are enumerated. Up to equivalence their number is 29.     

Conductive Composites Based on Metallocene Isotactic Poly(propylene): Preparation and Properties

Summary: The research deals with the preparation and the further comprehensive characterization of metallocene polypropylene-based composite materials by incorporation of carbon black nanoparticles. Composites containing up to 10 wt% of carbon black were prepared by direct melt mixing in a single screw extruder Brabender Extrusiograph type 30/25D with attached static mixer at melt temperature of 200 °C and a screw speed of 30 rpm, according to a two-step process. Some composites were treated with 3 wt% maleic anhydride grafted polypropylene (MAH-PP). The rheological behaviour of the miPP nanocomposites was determined by cone/plate rheological measurements at 180 °C. The composites were characterized by SEM for morphological details and uniaxial stress-strain measurements for determining the mechanical parameters. Electric conductivity of injection molded plates from these composites was investigated. The different miPPs studied are ranked in an ascending order according to their increasing molecular weight concerning the magnitude of their rheological parameters. The maleic anhydride compatibilizer leads to lower viscosity values even at high shear gradients and to better homogenization of the nanofiller in the polymer matrix. The processing conditions, carbon black concentration and viscosity of the virgin polymer have an impact on the final conductivity of the miPP/carbon black composites.     

A DFT Study of Electron Structure, Geometry, and Keto–Enol Tautomerism of 3-Oxopropionyl Halogenides

Summary. The electronic and geometry structures of all enol and diketoforms of 3-oxopropionyl halogenides were investigated at the B3LYP/3-21G** level of theory. The comparative study of their energies revealed that the enol forms of the compounds are more stable than cis- and trans-diketones. All cis-diketones (except Cl-containing one) have one imaginary frequency in their vibration spectra, i.e. they do not correspond to local or global minima on the potential hypersurface. The keto–enol transformations enolcis-diketone and enoltrans-diketone for a certain triad of tautomers/isomers pass through one transition state or in other words, the two conversions have one common maximum on the energy hypersurface. The energy barriers of the keto–enol conversions found for isolated molecules are quite high. Only for the enoldiketone conversions in solution the energy barriers are slightly reduced.     

3-Aryl-5-[(aryloxy)methyl]-3-[(1H-1,2,4-triazol-1-yl)methyl]-2-methylisoxazolidine derivatives. Synthesis and antifungal activity

The synthesis and antifungal activity of a novel series of 3-aryl-5-[(aryloxy)methyl]-3-[(1H-1,2,4-triazol-1-yl)-methyl]-2-methylisoxazolidines are described. The in vitro activity was evaluated in solid agar cultures against a variety of dermatophytes and yeast fungi, while in vivo activity was measured in an immune-compromised mouse model of systemic candidiasis. The activity of the title series was compared to that of ketoconazole and one derivative, the cis-3-(4-chlorophenyl)-5-(4-chlorophenyloxy)methyl analogue 5f was found to possess a similar potency in the in vivo assay. Structure-activity relationship correlations are also discussed.