New frontiers in hybrid materials: noble metal nanoparticles – supramolecular gel systems

The last decade has witnessed an increasing interest in the development of hybrid materials with novel properties. Noble metal NPs–gel materials represent a new class of hybrid composites, envisaged by many to have great potential for technological applications, as a consequence of the beneficial integration of the properties of both the NPs and the gelling compounds. This review article provides an up-todate account of the most interesting and inspiring works published in the field, especially focusing on their preparation and characterization. Some examples of practical uses of such intriguing materials are also described

Responsive aggregation-induced emissive supramolecular gels based on bis-cyanostilbene derivatives

In aromatic solvents, V-shaped bis-cyanostilbene derivative 1 forms stable and emissive gels which are capable of responding to light and, selectively, to TFA via a gel-to-sol transformation

Derivatives of nonsteroidal anti-inflammatory drugs and amino acids - synthesis, characterization and biological activity

Sintetizirana je serija novih strukturnih analoga 3,5-disupstituiranih hidantoina 5a-h s lipofilnim supstituentima na C-5, N-3 ili na oba atoma intramolekulskom ciklizacijom amida N-(1-benzotriazolkarbonil)aminokiselina 4a-h. Sintetizirani su derivati NSAID 6–12: reducirani derivati ketoprofena 6a,b, NSAID benzotriazolidi 7a-h, NSAID hidroksamske kiseline i njihovi derivati 8a-y, derivati ketoprofena 9a-i, 10a-f, 11a-f i 3-hidroksipropilamidi NSAID 12a-e. Reducirani derivati ketoprofena 6 pripravljeni su katalitičkim hidrogeniranjem ketoprofena uz Pd/C ili Pd/C(en). NSAID s karboksilnom funkcionalnom (ibuprofen, fenoprofen, diklofenak, indometacin, ketoprofen, 6a,b) u reakciji s kloridom 1-benzotriazol-karboksilne kiseline (1) dali su odgovarajuće NSAID benzotriazolide 7, koji su bili polazni spojevi u sintezi derivata NSAID 8–12. Razvijena je nova sintetska metoda za pripravu NSAID hidroksamskih kiselina i derivata 8, reakcijom NSAID benzotriazolida 7 i odgovarajućih hidroksilamina (hidroksilamin, N-metilhidroksilamin, O-metilhidroksilamin, O-etilhidroksilamin i O-benzilhidroksilamin) ili katalitičkim hidrogeniranjem O-benzilnih derivata NSAID hidroksamskih kiselina. Derivati ketoprofena 9, 10 i 3-hidroksipropilamidi NSAID 12 sintetizirani su iz NSAID benzotriazolida 7 i odgovarajućih amina, dok su derivati ketoprofena 11 sintetizirani katalitičkim hidrogeniranjem amida ketoprofena 10 uz Pd/C(en). Provedena su sljedeća biološka ispitivanja: antitumorsko, antimikrobno, antivirusno i antioksidacijsko djelovanje, inhibicija ureaze, lipooksigenaze i lipidne peroksidacije. Najbolje antitumorsko djelovanje pokazao je 8c, najbolje antimikrobno 8b,d, najbolje antivirusno 5a i 8y, a najbolje antioksidacijsko djelovanje 8o. Najjači inhibitor ureaze bio je 8f, a lipooksigenaze 11f. Najbolji inhibitor lipidne peroksidacije bio je 9e.3,5-Disubstituted hydantoin derivatives 5a-h with lipophilic substituents at C-5, N-3 or both atoms were prepared by the intramolecular cyclization of the corresponding N-(1-benzotriazolecarbonyl)amino acid amides 4a-h. The following NSAID derivatives 6–12 were prepared: the reduced ketoprofen derivatives 6a,b, NSAID benzotriazolides 7a-h, NSAID hydroxamic acids and their derivatives 8a-y, ketoprofen derivatives 9a-i, 10a-f, 11a-f and NSAID 3-hydroxypropylamides 12a-e. The reduced ketoprofen derivatives 6 were prepared by the catalytic hydrogenation of ketoprofen with Pd/C or Pd/C(en) catalyst. NSAIDs bearing carboxylic group (ibuprofen, fenoprofen, diclofenac, indomethacin, ketoprofen, 6a,b) reacted with 1-benzotriazole carboxylic acid chloride (1) affording benzotriazolides 7, which were the starting compounds in the synthesis of NSAID derivatives 8–12. A new synthetic method for the synthesis of NSAID hydroxamic acids and their derivatives was developed. They were obtained in the reaction of NSAID benzotriazolides 7 with an appropriate hydroxylamine (hydroxylamine, N-methylhydroxylamine, O-methylhydroxylamine, O-ethylhydroxylamine or O-benzylhydroxylamine) or by the catalytic hydrogenation of O-benzyl derivatives of NSAID hydroxamic acids. Ketoprofen derivatives 9, 10 and NSAID 3-hydroxypropylamides 12 were prepared from NSAID benzotriazolides 7, in the reaction with an appropriate amine, while compounds of the series 11 were obtained by the catalytic hydrogenation of ketoprofen amides 10 with Pd/C(en). The compounds were evaluated for their biological activity: antitumor, antimicrobial, antiviral and antioxidant activity, inhibition of urease, lipoxygenase and linoleic acid lipid peroxidation. The best antitumor activity was exerted by 8c, antimicrobial by 8b,d, antiviral by 5a and 8y, and antioxidant by 8o. The strongest inhibitor of urease was 8f, while 11f was the strongest inhibitor of lipoxygenase. Compoung 9e showed the highest inhibition of linoleic acid lipid peroxidation

Synthesis of Selected Naturally Occurring Glucosides of Volatile Compounds. Their Chromatographic and Spectroscopic Properties

Naturally occurring glucosides of benzyl alcohol, (±)-menthol, (+)-borneol, thymol, carvacrol and eugenol were synthesized by the Koenigs-Knorr-Zemplén method (yields 19.5–52.2 %). Their β-D-glucopyranosidic structures were determined by one- and two-dimensional homoand heteronuclear 1H and 13C NMR spectroscopy. The β-configuration was additionally confirmed by the hydrolysis with β-glucosidase. Tetraacetyl-β-D-glucopyranosides, as intermediates, were GC-MS analyzed. Diastereomeric β-glucoside tetraacetates of (±)-menthol were well separated on the HP-101 column. The mass spectra of glucopyranoside tetraacetates were mutually compared, as well as with the spectra of their aglycones

Synthesis of Selected Naturally Occurring Glucosides of Volatile Compounds. Their Chromatographic and Spectroscopic Properties

Naturally occurring glucosides of benzyl alcohol, (±)-menthol, (+)-borneol, thymol, carvacrol and eugenol were synthesized by the Koenigs-Knorr-Zemplén method (yields 19.5–52.2 %). Their β-D-glucopyranosidic structures were determined by one- and two-dimensional homoand heteronuclear 1H and 13C NMR spectroscopy. The β-configuration was additionally confirmed by the hydrolysis with β-glucosidase. Tetraacetyl-β-D-glucopyranosides, as intermediates, were GC-MS analyzed. Diastereomeric β-glucoside tetraacetates of (±)-menthol were well separated on the HP-101 column. The mass spectra of glucopyranoside tetraacetates were mutually compared, as well as with the spectra of their aglycones

Synthesis of selected naturally occurring glucosides of volatile compounds. Their chromatographic and spectroscopic properties

Naturally occurring glucosides of benzyl alcohol, (+/-)-menthol, (+)-borneol, thymol, carvacrol and eugenol were synthesized by the Koenigs-Knorr-Zemplen method (yields 19.5-52.2%). Their beta-D-glucopyranosidic structures were determined by one- and two-dimensional homo- and heteronuclear H-1 and C-13 NMR spectroscopy. The beta-configuration was additionally confirmed by the hydrolysis with P-glucosidase. Tetraacetyl-beta-D-glucopyranosides, as intermediates, were GC-MS analyzed. Diastereomeric beta-glucoside tetraacetates of (+/-)-menthol were well separated on the HP-101 column. The mass spectra of glucopyranoside tetraacetates were mutually compared, as well as with the spectra of their aglycones

Benzotriazole as a Synthetic Auxiliary

Benzotriazole is a very useful synthetic auxiliary with versatile applications in organic chemis¬try. We have used benzotriazole in the synthesis of various heterocyclic compounds (benzoxazine, quinazoline, triazinetrione, hydantoin, oxadiazine and diazepane derivatives), amino acid derivatives, car¬bamates, ureas, semicarbazides, carbazides, sulfonylureas, sulfonylcarbazides, hydantoic acids, non-steroidal antiinflammatory drug (NSAID) and primaquine derivatives, polymer-drug and thiomer-drug conjugates. The results have been published in more than 30 papers and here we give an overview of all syntheses. (doi: 10.5562/cca2124

Preparation of potentially porous, chiral organometallic materials through spontaneous resolution of pincer palladium conformers

Understanding the mechanism by which advanced materials assemble is essential for the design of new materials with desired properties. Here, we report a method to form chiral, potentially porous materials through spontaneous resolution of conformers of a PCP pincer palladium complex ({; ; 2, 6-bis[(di-t-butylphosphino)methyl]phenyl}; ; palladium(II)halide). The crystallisation is controlled by weak hydrogen bonding giving rise to chiral qtz-nets and channel structures, as shown by 16 such crystal structures for X = Cl, and Br with various solvents like pentane and bromobutane. The fourth ligand (in addition to the pincer ligand) on palladium plays a crucial role ; the chloride and the bromide primarily form hexagonal crystals with large 1D channels, whereas the iodide (presumably due to its inferior hydrogen bonding capacity) forms monoclinic crystals without channels. The hexagonal channels are completely hydrophobic and filled with disordered solvent molecules. Upon heating loss of solvent occurs and the hexagonal crystals transform into other non-porous polymorphs. Also by introducing strong acid, the crystallisation process can be directed to a different course, giving several different non-porous polymorphs. In conclusion a number of rules can be formulated dictating the formation of hexagonal channel structures based on pincer palladium complexes. Such rules are important for a rational design of future self-assembling materials with applications in storage and molecular recognition