The Diels-Alder reaction of various reactive dienophiles with cyclopentadiene is reported. Rather than cracking dicyclopentadiene in a separate step, the reagents were mixed in a sealed tube and the reactions carried out at 185C. Conversion to the adducts is dependent on the nature of the dienophile and the reaction time. In those cases where stereochemistry is relevant, the endo/exo ratios are reported and compared to those reported at lower temperatures.

Vitamin E, consisting of the groups of tocotrienols 5 and tocopherols 6, is the biologically most important fat-soluble antioxidant. In the context of total synthesis of these compounds,^[1] the Zr-mediated carboalumination methodology^[2] was applied. Alkyne 3, easily available from (E)-geranylacetone (4), delivers (all-E)-alkenyl iodide 2 for the coupling with (enantiomerically pure) aldehydes 1 to various stereochemically defined homologous trienols 5, e.g. serving as starting materials for the highly stereoselective Ir-catalyzed asymmetric hydrogenation to tocopherols 6.^[3] [1] a) T. Netscher, Chimia 1996, 50, 563; T. Netscher, Vitamins and Hormones 2007, 76, 155; b) C. Rein, P. Demel, R.A. Outten, T. Netscher, B. Breit, Angew. Chem. Int. Ed. 2007, 46, 8670; c) T. Netscher, M. Scalone, R. Schmid in Asymmetric Catalysis on Industrial Scale, H.-U. Blaser, E. Schmidt (eds.), Wiley-VCH, Weinheim, Germany, 2004, p. 71. [2] a) E. Negishi, Pure Appl. Chem. 1981, 53, 2333; b) S. Huo, E. Negishi, Org. Lett. 2001, 3, 3253. [3] S. Bell, B. Wüstenberg, S. Kaiser, F. Menges, T. Netscher, A. Pfaltz, Science 2006, 311, 642.

The title compound was prepared from 2,6-difluorophenol in four steps. Acetylation, followed by nitration, reduction to the amine and diazotization/azide formation proceeded in the expected fashion. A copper-catalyzed Huisgen cyclization between the compound and phenylacetylene was carried out as a model and the triazole isolated. The propargyl ester of naproxen was prepared (naproxen/propargyl alcohol/carbodiimide) and the subsequent click reaction carried out. It is expected that this strategy will afford access to materials with dual biological activity.

Ab-initio levels of theory using 6-31+G(d,p) basis set have been carried out to investigate the Isomeric structures, energies and properties of mononsilacyclopropylidenoids, C₂H₄SiMX (where M= Na or Li, and X= F, Cl or Br). The theoretical calculations depict that each of them has three stationary structures: silacyclopropylidenoid (S), tetrahedral (T), and inverted (I). All of the silacyclopropylidenoid (S) forms are energetically more stable than others except for S-LiF, whereas all of the tetrahedral (T) forms are the most unstable ones except for T-NaF. Energy differences between S, T, and I forms range from 0.60 to 8.70 kcal/mol. Moreover, natural bond orbitals (NBO), and frontier molecular orbitals (FMO) were achieved in this computational study.

Triethylammonium 4-aryl-3,5-dicyano-6-oxo-1,4,5,6-tetrahydropyridine-2-olates were obtained by reaction of (E)-3-aryl-2-cyanoacrylamides with 1-cyanoacetyl-3,5-dimethylpyrazole in the presence of 1.5 eq. of Et₃N (20 °C, acetone) in 55-98% yields.

The lower molecular weight hydrocarbons that can be mapped on the buckminsterfullerene (C₆₀) structure are commonly known as "buckybowls" or "geodesic polyarenes" and have the distinctive characteristics of preserving the curvature and aromaticity of fullerene. These bowl-shaped structures are expected to be quite rigid. Nevertheless, the smaller members of the family, in spite of its substantial curvature are surprisingly flexible undergoing rapid bowl-to-bowl inversion in solution as evidenced by the dynamic NMR behavior of C₂₀H₁₀ (corannulene) and several of its derivatives. With the aim of gaining understanding in the bowl-to-bowl inversion, the present theoretical study has explored the effect that substitution of some of the hydrogen atoms of corannulene has on this process. The model systems studied have the formula C₂₀H_10-nR_n with R = -Cl, -Br, -C≡CH, -CH₃ and n = 0, 2, 4, 5, 6, 8, and 10. It is observed that the bowl depth is reduced only by high substitution levels or by a substitution pattern that conduces to important peri interactions. Full substitution with bulky groups causes a pronounced repulsion and the deformation of the transition structure for bowl inversion that otherwise is planar. The activation barrier for the inversion – bowl depth data fit an empirical quartic/quadratic function used previously in similar systems but the coefficients of the fitting don\'t follow the predicted substituent independency.

A library of 2-amino-9-aryl-3-cyano-4-methyl-7-oxo-6,7,8,9-tetrahydropyrido[2\',3\':4,5]thieno[2,3-b]pyridines which recently have been reported as selective progesterone receptor agonists was synthesized by ternary condensation of N-methylmorpholinium 4-aryl-3-cyano-6-oxo-1,4,5,6-tetrahydropyridine-2-thiolates with malononitrile and acetone, and alternatively by reaction of bis(4-aryl-3-cyano-6-oxo-1,4,5,6-tetrahydropyridine-2-yl)disulfides with acetone and malononitrile in basic media. The mechanism, scope and limitations of the reactions are discussed.

Bitopic pyrazole-containing ligands attract interest because of their potential use as building blocks for crystal engineering and for synthesis of heterobimetallic complexes for catalysis. Several new bitopic pyrazole-containing ligands were prepared from the corresponding pyrazoles and tetrahalogen- or tetratosyloxy derivatives of o-xylene and neopentane in a superbasic medium (KOH-DMSO). The reaction of unsubstituted pyrazole with 1,3-dibromo-2,2-dibromomethylpropane yields a new tetrapyrazole ligand with a neopentane backbone, while no reaction occurs in case of 3,5-dimethylpyrazole. The product represents a bitopic ligand comprising two 1,3-bis(pyrazol-1-yl)propane units directly linked together. The use of tetratosyloxy- instead of tetrabromo-derivative gives previously unknown 1,1-bis(3,5-dimethylpyrazol-1-ylmethyl)oxetane, while the unsubstituted pyrazole in the same conditions yields a mixture tetrapyrazolyl-neopentane and dipyrazolyloxetane derivatives. A new bitopic ligand with aromatic o-xylene linker inaccessible by other routes was prepared from o-bis(dibromomethyl)benzene and pyrazole in a superbasic KOH-DMSO medium. In case of 3(5)-methylpyrazole and 3,5-dimethylpyrazole no products could be isolated, apparently due to steric hindrance.

Since the optically active quinuclidin-3-ol is an important intermediate in the preparation of physiologically or pharmacologically active compounds, new biocatalytic method for the efficient production of chiral quinuclidin-3-ols was examined. Butyrylcholinesterase (BChE; EC 3.1.1.8) was chosen as a biocatalyst in a preparative kinetic resolution of enantiomers. [1-3] In this study a series of racemic, (R)- and (S)- esters of quinuclidin-3-ol and acetic, benzoic, phthalic and succinic acids were synthesized as well as their racemic and chiral, quaternary N-benzyl, meta and para N-bromobenzyl and meta and para N-methylbenzyl derivatives. After the resolution, all N-benzyl protected groups were successfully removed by catalytic transfer hydrogenation with ammonium formate (10% Pd-C). The stereoselectivity of hydrolysis with horse serum BChE was investigated. The rates of hydrolyses were monitored at 37 ^oC in 0.1 M phosphate buffer pH 7.4 (2 mM concentrations of racemic esters). Hydrolyses studies confirmed [3] that all (R)-enantiomers of prepared esters are much better substrates than (S)-enantiomers. In the case of N-benzyl protected esters, the difference for all prepared esters was even more pronounced. Introduction of bromine atom or methyl group in the meta or para position on the phenyl ring of benzyl moiety resulted in a remarkable improvement of the stereoselectivity: (R)-acetates and (S)-alcohols were isolated in a high optical purity (> 95 %). Thus, optically pure quinuclidin-3-ols can be prepared in the high yields and enantiopurity by the esterification, quarternization with benzyl bromide, BChE-catalysed hydrolysis and finally catalytic transfer hydrogenation. [1] Ines Primozic, Tomica Hrenar, Srdjanka Tomic and Zlatko Meic, Journal of Physical Organic Chemistry 15 (2002) 608-614. [2] Ines Primozic, Tomica Hrenar, Srdjanka Tomic and Zlatko Meic, European Journal of Organic Chemistry (2003) 295-301. [3] Ines Primozic, and Srdjanka Tomic, Croatica Chemica Acta 84 (2011) 245-249.

New thermotropic liquid crystals containing benzoxazole core and alkanoyloxy chain at the end group of the molecules (C_n-1H_2n-1COO-, n = 14, 16, 18) was synthesized. The present compounds are enantiotropic smectic A liquid crystals.It was also found that the end groups of the molecules and polar chloro substituent at the benzoxazole fragment had effect on the mesomorphic properties.