Imidazolidin-4-ones via (3+2) cycloadditions of aza-oxyallyl cations onto ()-arylideneanilines.

In the course of our studies on the chemistry of oxyallyl species we uncovered a new (3+2) cycloaddition of aza-oxyallyl systems, generated in situ from -benzyloxy-2-chloroamides in the presence of NEt, onto -arylimines yielding imidazolidin-4-ones in moderate to good yields. The cycloadditions are regioselective. Computational modelling using DFT at the M062×/6-311+G** level is in support the observed regioselectivities.

Synthesis of Oleanolic Acid Analogues and Their Cytotoxic Effects on 3T3 Cell Line.

Background: Oleanolic acid (OA) is a known natural compound with many important biological activities. Thirteen oleanolic acid derivatives linked at C-3 and C-28 were synthesized and their structures were confirmed by 1H- and 13C NMR and mass spectral analyses. Among them, compounds 4, 6, 8-10, 12, 13 were synthesized for the first time.

Synthesis of Novel UV Absorbers Bisindolylmethanes and Investigation of Their Applications on Cotton-Based Textile Materials.

Nowadays modified textiles, especially UV-protective, antibacterial and antimicrobial ones, have become the focus of great interest. In this study, several new UV absorbers, bis(indolyl)methane derivatives, were synthesized and grafted onto polyvinyl alcohol polymer (PVA). Their application properties on cotton-based textile materials were determined; the UV protection factor values of the modified fabrics were measured (UPF); and the antibacterial features of the fabrics were tested.

Aryl- and heteroaryl substituted tandospirones as possible antidepressant drugs.

Nowadays, heterocyclic compounds which have a nitrogen atom on the structure, such as pharmacological products, pesticides and antimicrobials can be demonstrated by biologically-active groups that serve the pharmaceutical industry and they are still important in this field. Various cyclization reactions form the basis of the literature on the syntheses of heterocyclic compounds. NArylpiperazines are a class of heterocyclic compounds that play an important role in organic synthesis and are generally found as fragments in receptor ligands and natural products.

Effect of allylic groups on S(N)2 reactivity.

The activating effects of the benzyl and allyl groups on S(N)2 reactivity are well-known. 6-Chloromethyl-6-methylfulvene, also a primary, allylic halide, reacts 30 times faster with KI/acetone than does benzyl chloride at room temperature. The latter result, as well as new experimental observations, suggests that the fulvenyl group is a particularly activating allylic group in S(N)2 reactions.

Reductive Heck reactions and [3+2] cycloadditions of unsaturated N,N'-bistricyclic imides.

The C-C coupling of N,N'-bis(5-norbornene-2,3-dicarboximide) (3) and N,N'-bis(7-oxa-5-norbornene-2,3-dicarboximide) (6) with aryl and heteroaryl iodides gave under reductive Heck conditions the C-aryl(hetaryl), substituted N,N'-bistricyclic imides 7a-f and 8a,b. The fused spiro-1,3-indandionolylpyrrolidine compounds, 9, 10 and 11 were also obtained from ninhydrine, sarcosine and 3 or 6 via [3+2]cycloaddition.

1,3-dipolar cycloaddition reactions of N-methyl-substituted tricyclic imides.

The [3+2] cycloadditions of N-methyl derivatives of unsaturated imides with various nitrile oxides to yield new bridged isoxazoline derivatives with potential biological activity is described.

The hydroarylation reaction--scope and limitations.

The synthetic potential of stereoselective, palladium-catalyzed hydro(het)arylation reactions of bi-, tri- and tetracyclic (hetero)alkenes in the presence of phospines and arsines as highly efficient ligands was studied. The mechanism of this reductive Heck reaction becomes more complex in the case of benzonorbornenes. Hydroarylation of diazabicyclo-[2.

Reductive Heck reactions of N-methyl-substituted tricyclic imides.

The palladium-catalyzed hydroarylation of N-methyl-substituted tricyclic imides was studied in order to find a new stereoselective access to a series of new exo-aryl(hetaryl)-substituted tricyclic N-methylimides.

Supramolecular structure of racemic 5-hydroxy-4-(4-methoxyphenyl)-10-oxa-4-azatricyclo[5.2.1.0(2,6)]dec-8-en-3-one.

The structure of the title compound, C(15)H(15)NO(4), comprises a racemic mixture of chiral molecules containing five stereogenic centres. The cyclohexane ring tends towards a boat conformation and the two tetrahydrofuran rings adopt envelope conformations. Molecules are linked into sheets parallel to (100) by a combination of O-H.

Unusual endoperoxide isomerizations: a convenient entry into 2-vinyl-2-cyclopentenones from saturated fulvene endoperoxides.

An unusual peroxide base promoted isomerization was uncovered. Saturated endoperoxides derived from fulvenes give rise to 2-vinyl-2-cyclopentenones upon treatment with DBU in CH(2)Cl(2) in a one-pot reaction. This methodology was applied to a convenient synthesis of dihydrojasmone.

Epibatidine alkaloid chemistry: 5. Domino-Heck reactions of azabicyclic and tricyclic systems.

Palladium-catalyzed hydroarylations and additional domino reactions of aza-bicyclic and tricyclic norbornene derivatives were investigated and a series of new epibatidine analogues were synthesized.

Synthesis of new pyrazolothiazole derivatives from 4-thiazolidinones.

The synthesis of new 2,3,5,6-aryl substituted tetrahydro-2H-pyrazolo[3,4-d]- thiazoles 4a-j as potential biologically active compounds by the cyclocondensation of phenyl hydrazine with new 5-arylidene derivatives 2a-j of 2,3-disubstituted-1,3- thiazolidin-4-ones 1a-e is reported.

Palladium-catalyzed, stereoselective rearrangement of a tetracyclic allyl cyclopropane under arylation.

The first example of a pi,sigma domino-Heck reaction under concomitant rearrangement of the tetracyclic allylcyclopropane endo,exo-bishomobarrelene (5) is reported; the stereoselective reaction proceeds via an intramolecular insertion of a primarily-formed carbopalladation intermediate into a strained cyclopropane C-C sigma-bond, giving 9.