bluuebunny/crossref_metadata_2025 huggingface dataset:
New Route to 3-Alkylthiazolo[3,2-a]benzimidazole Derivatives
Authors: Roussel Christian , Andreoli Federico , Roman Mihaela , Hristova Maria , Vanthuyne Nicolas
Published: October 2008

3-Alkyl-thiazolo[3,2-a]benzimidazole derivatives are obtained in high yieldsvia the corresponding 4-alkyl-N-3-(2-aminophenyl)-thiazoline-2-thiones which are easilyprepared from 1,2-diaminobenzene, CS2 and halogenoketones. This new route comparesadvantageously with the classical mercaptobenzimidazole routes in term of simplicity,isolated yields and availability of the starting materials.
Valence Topological Charge-Transfer Indices for Reflecting Polarity: Correction for Heteromolecules
Authors: Torrens F.
Published: October 2008

Valence topological charge-transfer (CT) indices are applied to the calculationof dipole moments μ. The μ calculated by algebraic and vector semisums of the CTindices are defined. The model is generalized for molecules with heteroatoms andcorrected for sp3-heteromolecules. The ability of the indices for the description of themolecular charge distribution is established by comparing them with μ of the valence-isoelectronic series of cyclopentadiene, benzene and styrene. Two CT indices, μvec(vector semisum of vertex-pair μ) and μvecV (valence μvec) are proposed. The μvecVbehaviour is intermediate between μvec and μexperiment. The correction is produced in thecorrect direction. The best results are obtained for the greatest group. Inclusion of theheteroatom in the π-electron system is beneficial for the description of μ, owing to eitherthe role of additional p and/or d orbitals provided by the heteroatom or the role of stericfactors in the π-electron conjugation. The steric effect is almost constant along the seriesand the dominating effect is electronic. Inclusion of the heteroatom enhances μ, whichcan improve the solubility of the molecule. For heteroatoms in the same group, the ringsize and the degree of ring flattering are inversely proportional to their electronegativity.
The Preparation and Characterization of 5-Substituted-4-chloro-1,2,3-dithiazolium Salts and their Conversion into 4-Substituted-3-chloro-1,2,5-thiadiazoles
Authors: Koutentis P.
Published: October 2008

A series of monosubstituted acetonitriles were treated with disulfur dichloride atroom temperature in CH2Cl2 to afford 5-substituted-4-chloro-1,2,3-dithiazolium chlorides 1.Where the 5-substituent was not a good leaving group the chloride salts were converted intothe corresponding perchlorate salts 2 which were sufficiently stable and soluble to provideboth 1H- and 13C-NMR and cyclic voltammetry data. Several of the dithiazolium chlorideswere converted into their corresponding 4-substituted-3-chloro-1,2,5-thiadiazoles 13 ontreatment with aqueous ammonia. Mechanisms for all reactions are proposed.
Synthesis and X-ray Structure of a New Pyrrolo[1,2-b]-pyridazine Derivative
Authors: Caira Mino R. , Dumitrascu Florea , Draghici Constantin , Dumitrescu Denisa , Cristea Mihaela
Published: October 2008

The synthesis, characterization and X-ray crystal structure of 2-(4-chloro-phenyl)-7-methylpyrrolo[1,2-b]pyridazine are reported. The compound crystallizes in thespace group P21/c (No.14) with a =3.8568(1), b = 11.0690(3), c = 26.4243(7) å, β =92.777(1)° and Z = 4. Accurate molecular parameters for the novel heterocyclic systemwere obtained from intensity data collected at 113K. The molecule assumes a planarconformation in the crystal and the packing is based on π-π stacking with interplanarspacing 3.400 å, typical of aromatic molecules with potential for displaying usefuloptical properties.
Synthesis of Pyrrolo[2,3-d][1,2,3]thiadiazole-6-carboxylates via the Hurd-Mori Reaction. Investigating the Effect of the N-Protecting Group on the Cyclization
Authors: Stanetty P, , Turner M. , Mihovilovic M.
Published: October 2008

A route to methyl pyrrolo[2,3-d][1,2,3]thiadiazole-6-carboxylates as potential plant activators and inducers of systemic acquired resistance (SAR) is reported. A synthetic strategy based on cyclization of the thiadiazole ring system utilizing thionyl chloride via the Hurd-Mori protocol as key step was developed. Success of the ring closure reaction turned out to be highly dependent on the nature of the N-protecting group of the pyrrolidine precursor. While electron donors such as alkyl gave only poor conversion to the required 1,2,3-thiadiazoles, an electron withdrawing substituent such as methyl carbamate gave superior yields.
Synthesis of 4-Amino-4,5-dihydro-1H-1,2,4-triazole-5-ones and their Isatin-3-imine Derivatives
Authors: Kahveci Bahittin
Published: October 2008

Iminoester hydrochlorides 1 have been synthesized. These compounds werethen converted into ester ethoxycarbonyl hydrazones 2, from which in turn a new seriesof substituted 4-amino-4,5-dihydro-1H-1,2,4-triazole-5-ones, 3, was then prepared.Finally a set of isatin imine derivatives 4 was obtained from the reaction of compounds 3with isatin. The structures of all the new synthesized compounds were confirmed byelemental analyses, IR, 1H-NMR and 13C-NMR spectra.
Diastereoselective Synthesis of 2-Phenylselenenyl-1,3-anti-Diols and 2-Phenylselenenyl-1,3-anti-Azido-Alcohols via Hydroxyand Azido-Selenenylation Reactions
Authors: Riela Serena , Aprile Carmela , Gruttadauria Michelangelo , Meo Paolo  Lo , Noto Renato
Published: October 2008

A method to synthesize 2-phenylselenenyl-1,3-anti-diols and 2-phenyl- selenenyl-1,3-anti-azidoalcohols via hydroxy- or azido-selenenylation of trans-allylic alcohols is reported. Moreover, the first example of hydroxyl-selenenylation of an allylic azide is presented. Yields ranging from moderate to good and diastereomeric ratios up to 95:5 are achieved.
An Aromatic Iodination Method, with Iodic Acid Used as the Only Iodinating Reagent
Authors: Krassowska-Swiebocka Barbara , Prokopienko Grazyna , Skulski Lech
Published: October 2008

Benzene, halobenzenes, and a number of more or less deactivated arenes,including nitrobenzene, readily reacted in anhydrous HIO3/AcOH/Ac2o/conc. H2SO4mixtures to probably give ArIO2 intermediates or other hypervalent species (notisolated). The final reaction mixtures were poured into excess aq. Na2SO3 solution (areductant) to give the purified iodinated products in 39-83% yields.
A Comparison of Microwave-Accelerated and Conventionally Heated Iodination Reactions of Some Arenes and Heteroarenes, Using ortho-Periodic Acid as the Oxidant†
Authors: Sosnowski Maciej , Skulski Lech
Published: October 2008

A fast and simple method for the oxidative iodination of some activated arenes and heteroarenes, either under microwave irradiation or by conventional heating, is reported, using diiodine and ortho-periodic acid as the oxidant. The reactions were carried out in hot 95% ethanol under a reflux condenser. For the microwave assisted reactions, the reaction times were always notably shortened, but the yields were nearly the same as those afforded by the conventional method.
Synthesis and Cyclizations of N-(2,3-, 3,4- and 3,5-Dimethylphenyl)-β-alanines
Authors: Vaickelioniene Rita , Mickevicius Vytautas , Mikulskiene Gema
Published: October 2008

A series of 1-aryl substituted dihydro-, 5-methyldihydro- and 6-methyl-dihydro-2,4(1H,3H)pyrimidinediones and their 2-thio analogues were obtained byreaction of the corresponding β-alanines or α-methyl- and β-methyl-β-alanines with ureaor potassium thiocyanate. The reaction of N-(2,3- and 3,5-dimethylphenyl)-α-methyl-β-alanines with ethyl acetoacetate gave 1-(2,3- or 3,5-dimethylphenyl)-2,5-dimethyl-1,4,5,6-tetrahydro-4(1H)pyridones. The combined spectral data obtained by 1H-, 13C-,1 H/13C (HETCOR) NMR and IR provided useful information about the structure of theproducts synthesized in this work.
Investigation of DNA-protein Sequence-Specific Interactions with a ds-DNA Array
Authors: Bai Yunfei , Ge Qinyu , Wang Jinke , Li Tongxiang , Liu Quanjun , Lu Zuhong
Published: October 2008

The sequence specific recognitions between DNAs and proteins play important roles in many biological functions. The use of double-stranded DNA arrays (ds-DNA arrays) for studying sequence specific recognition between DNAs and proteins is a promising method. Here we report the use of a ds-DNA probe with multi operation sites of restriction proteins in the middle sequence to investigate DNA-protein sequence-specific interactions including methylation. We arranged EcoR I site and Rsa I site on the same duplex DNA probe to fabricate ds-DNA arrays. We used the ds-DNA arrays to study DNA-restriction enzyme reactions before and after duplex DNA methylation under different probe concentration and reaction time conditions. Our results indicated that the ds-DNA arrays can be further biochemically modified and made accessible for interactions between DNAs and proteins in complex multi-step gene-regulation processes.
The Synthesis and Herbicidal Activity of 1-Alkyl-3-(α-hydroxysubstituted benzylidene)pyrrolidine-2,4-diones
Authors: Zhu You-Quan , Yao Chang-Sheng , Zou Xiao-Mao , Hu Fang-Zhong , Liu Bin , Li Yong-Hong , Yang Hua-Zheng
Published: October 2008

In the search for better herbicides a series of 1-alkyl-3-(α-hydroxy-(un)substituted benzylidene)pyrrolidine-2,4-diones were prepared and their structure-activity relationships studied. All their structures have been confirmed by 1H-NMR andelemental analysis. The preliminary bioassay results indicated that some of them have highherbicidal activity against annual dicotyledonous and monocotyledonous plants.
1H- and 13C-NMR Analysis of a Series of 1,2-Diaryl-1H-4,5-dihydroimidazoles
Authors: Salerno Alejandra , Perillo Isabel  A.
Published: October 2008

An analysis of the 1H- and 13C-NMR spectra of a series of 1,2-diaryl-1H-4,5-dihydroimidazoles and comparisons with 4,5-dihydroimidazoles having differentsubstitution patterns are presented. The influence of different 1-aryl and 2-aryl groupsubstituents on spectroscopic parameters of the heterocyclic ring and on the contributionsof possible mesomeric structures in the system was determined. Spectroscopic featuresare coherent with the presence of two conjugated systems (Ar1-N and Ar2-C=N) whichcompete with the delocalization characteristics of the amidine system.
Solution-phase Synthesis of a Combinatorial Library of 3-[4-(Coumarin-3-yl)-1,3-thiazol-2-ylcarbamoyl]propanoic acid Amides
Authors: Zhuravel I. , Kovalenko S. , Vlasov S. , Chernykh V.
Published: October 2008

The parallel solution-phase synthesis of a new combinatorial library of 3-[4-(R1-coumarin-3-yl)-1,3-thiazol-2-ylcarbamoyl]propanoic acid amides 9 has been developed. The synthesis involves two steps: 1) the synthesis of core building blocks – 3- [4-(coumarin-3-yl)-1,3-thiazol-2-ylcarbamoyl]propanoic acids, 6 – by the reaction of 3-(ω-bromacetyl)coumarins 1 with 3-amino(thioxo)methylcarbamoylpropanoic acid (5); 2) the synthesis of the corresponding 3-[4-(coumarin-3-yl)-1,3-thiazol-2-yl- carbamoyl]propanoic acids amides 9 using 1,1’-carbonyldimidazole as a coupling reagent. The advantages of the method compared to existing ones are discussed.
Influence of the Dielectric Medium on the Carbonyl Infrared Absorption Peak of Acetylferrocene
Authors: Alvarado Y. , Peña-Suárez J. , Cubillán N. , Labarca P. , Caldera-Luzardo J. , López-Linares F.
Published: October 2008

The solvent effect on the position of the carbonyl vibrational stretching ofacetylferrocene in aprotic media was studied in this work. The solvent-induced shifts in thisorganometallic compound were interpreted in terms of the alternative reaction field model(SCRF-MO) proposed by Kolling. In contrast to the established trends for carbonyl groupsin organic systems, the results suggest that the continuum models for the reaction field arenot adequate and that the influence of dipolarity-polarizability described by aninhomogeneous coupling function θ (ε ) L(n 2 ) that assumes optical dielectric saturation isresponsible for the carbonyl band shift and, there is empirical evidence that the effect offield-induced intermolecular interaction on band shift, interpreted in terms of the van derWaals forces from the solvent, have a important contribution to this phenomena.
5-Furan-2yl[1,3,4]oxadiazole-2-thiol, 5-Furan-2yl-4H [1,2,4] triazole-3-thiol and Their Thiol-Thione Tautomerism
Authors: Koparır M. , Çetin A. , Cansız A.
Published: October 2008

5-Furan-2-yl[1,3,4]oxadiazole-2-thiol (Ia) and 5-furan-2-yl-4H-[1,2,4]-triazole-3-thiol (Ib) were synthesized from furan-2-carboxylic acid hydrazide. Mannich basesand methyl derivatives were then prepared. The structures of the synthesized compoundswere confirmed by elemental analyses, IR and 1H-NMR spectra. Their thiol-thione tautomericequilibrium is described.
A Novel Approach in Cinnamic Acid Synthesis: Direct Synthesis of Cinnamic Acids from Aromatic Aldehydes and Aliphatic Carboxylic Acids in the Presence of Boron Tribromide
Authors: Chiriac C. , Tanasa F. , Onciu M.
Published: October 2008

Cinnamic acids have been prepared in moderate to high yields by a new direct synthesis using aromatic aldehydes and aliphatic carboxylic acids, in the presence of boron tribromide as reagent, 4-dimethylaminopyridine (4-DMAP) and pyridine (Py) as bases and N-methyl-2-pyrolidinone (NMP) as solvent, at reflux (180-190°C) for 8-12 hours.
A General Synthesis of Tris-Indole Derivatives as Potential Iron Chelators
Authors: Sears R. , Carpenter R. , Whitlock C.
Published: October 2008

The development of a novel route for the synthesis of a new class of compounds is described. The first tripodal, tris-indole amines are prepared by straightforward routes.
Reaction of Nitrilimines and Nitrile Oxides with Hydrazines, Hydrazones and Oximes
Authors: Ferwanah Abdel-Rahman  S. , Awadallah Adel  M.
Published: October 2008

This review article discusses the reaction of nitrilimines and nitrile oxides with hydrazines, hydrazones, and oximes. Three reaction modes were observed. The article mainly covers our work published over the last fifteen years, in which interesting heterocyles such as oxadiazoles, triazoles, and tetrazines were synthesized and fully characterized.
Microwave-Assisted Amination of a Chloropurine Derivative in the Synthesis of Acyclic Nucleoside Analogues
Authors: Lanver A. , Schmalz H.-G.
Published: October 2008

An efficient protocol for the amination of 6-chloropurine derivatives through nucleophilic aromatic substitution under microwave irradiation was developed and applied to the synthesis in two steps of a series of new acyclic nucleosides (acyclovir analogues) starting from commercially available compounds.
A Novel Aromatic Iodination Method, with Sodium Periodate Used as the Only Iodinating Reagent
Authors: Luliński Piotr , Sosnowski Maciej , Skulski Lech
Published: October 2008

Benzene, halobenzenes and some deactivated arenes readily reacted inanhydrous NaIO4/AcOH/Ac2O/concd. H2SO4 mixtures to afford, after quenching withexcess aqueous Na2SO3 solution (a reducing agent), purified iodinated products in 27-88% yields. This novel method of aromatic iodination is simple, fairly effective andenvironmentally safe.
Investigations on the Formation of 4-Aminobicyclo[2.2.2]-octanones
Authors: Seebacher Werner , Kröpfl Dietmar , Belaj Ferdinand , Saf Robert , Hüfner Antje , Weis Robert
Published: October 2008

Benzylidene acetone reacts with thiocyanates derived from secondary amines in a one-pot reaction to give 4-aminobicyclo[2.2.2]octan-2-ones. The reaction mixture was investigated for the presence of possible intermediates using GC-MS. These intermediates – diketones and enamines – were prepared and exposed to the same reaction conditions to examine the reaction mechanism. The reaction of ethyl styryl ketone with thiocyanates of secondary amines yielded cyclohexanone derivatives instead of the expected bicyclo- octanones. Their structures were established by means of a single crystal structure analysis.
Thermal Behaviour, Biological Activity and Conformational Study of a [Methoprene/β-Cyclodextrin] Complex in a Smoke Generating Formulation
Authors: Audino Paola  González , Masuh Hector , Zerba Eduardo
Published: October 2008

Methoprene, an insect growth regulator, was complexed with β-cyclodextrin, yielding a stable inclusion complex. TGA, X-ray powder diffraction and conformational analysis have been used to confirm the nature of this inclusion complex. The interaction between methoprene and β-cyclodextrin was investigated by means of Molecular Mechanics. The results account for the formation of a 1:1 inclusion complex stabilised by Van der Waals forces and hydrogen bonds. The [methoprene–β-cyclodextrin] complex included in smoke generating formulations and protected from thermal decomposition by the foaming agent azodicarbonamide was shown to be stable enough to release methoprene in fumes with good yields. The improved stabilty of the methoprene complex showed a correlation with increased biological activity against Musca domestica.
Functionalization of 6-Nitrobenzo[1,3]dioxole with Carbonyl Compounds via TDAE methodology
Authors: Amiri-Attou Ouassila , Terme Thierry , Vanelle Patrice
Published: October 2008

We report herein the synthesis of substituted 2-(6-nitrobenzo[1,3]dioxol-5-yl)-1- aryl ethanols and 2-(6-nitrobenzo[1,3]dioxol-5-yl)-propionic acid ethyl esters from the reaction of 5-chloromethyl-6-nitrobenzo[1,3]dioxole with various aromatic carbonyl and α- carbonyl ester derivatives using the tetrakis(dimethylamino)ethylene (TDAE) methodology.
Synthesis of Some Phenylpropanoid Monoglycerides via the Mitsunobu Protocol
Authors: Batovska Daniela  I. , Kishimoto Takao , Bankova Vassya  S. , Kamenarska Zornitsa G. , Ubukata Makoto
Published: October 2008

Natural monoglycerides of cinnamic, ferulic and p-coumaric acids were synthesized in good to high overall yields from isopropylidene glycerol via the Mitsunobu reaction and further deprotection of the corresponding acetonides with Amberlyst 15. The method avoids the need of protection of the phenolic hydroxyls. During the Mitsunobu esterifications a strong influence of the acid strength on the efficacy and outcome of the reaction was observed.
Experimental and Theoretical Studies on the Functionalization Reactions of 4-Benzoyl-1,5-Diphenyl-1H-Pyrazole-3-Carboxylic Acid and Acid Chloride with 2,3-Diaminopyridine
Authors: Yıldırım Ismail , Kandemirli Fatma , Demir Elif
Published: October 2008

The 1H-pyrazole-3-carboxylic acid 2 was converted in good yield (69%) into the corresponding 1H-pyrazole-3-carboxamide 5 via reaction of the acid chloride 3 with 2,3- diaminopyridine (4). A different product, the 3H-imidazo[4,5-b] pyridine derivative 6, was formed from the reaction of 3 with 4 and base in benzene for 5 hours. The structures of the synthesized compounds were determined spectroscopically. The mechanism of the reaction between 3 and 4 was examined theoretically.
Epoxidation and Reduction of DHEA, 1,4,6-Androstatrien-3-one and 4,6-Androstadien-3β,17β-diol
Authors: Ma Eunsook , Kim Eunjeong
Published: October 2008

Dehydroepiandrosterone (DHEA) reacted with m-chloroperoxybenzoic acid(m-CPBA) to form 3β-hydroxy-5α,6α-epoxyandrostan-17-one (1), but it did not reactwith 30% H2O2. 1,4,6-Androstatrien-3,17-dione (2) was obtained from DHEA and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone in dioxane. Compound 2 was reacted with 30%H2O2 and 5% NaOH in methanol to give 1α,2α-epoxy-4,6-androstadien-3,17-dione (3),which was stereoselectively reduced with NaBH4 to form 1α,2α-epoxy-4,6-androstadien-3β,17β-diol (7) and reacted with Li metal in absolute ethanol-tetrahydrofuran mixture togive 2-ethoxy-1,4,6-androstatrien-3,17-dione (8). Compound 2 was also epoxidized withm-CPBA in dichloromethane to afford 6α,7α-epoxy-1,4-androstadien-3,17-dione (4),which was reacted with NaBH4 to synthesize 6α,7α-epoxy-4-androsten-3β,17β-diol (9).Compound 4 was reduced with Li metal in absolute ethanol-tetrahydrofuran mixture toform 7β-ethoxy-6α-hydroxy-1,4-androstadien-3,17-dione (10). Compound 2 was reducedwith NaBH4 in absolute ethanol to form 4,6-androstadien-3β,17β-diol (5), which wasreacted with 30% H2O2 to give the original compound, but which reacted with m-CPBAto give 4β,5β-epoxy-6-androsten-3β,17β-diol (6).
Open Access and Author’s Open Choice
Authors: Lin Shu-Kun
Published: October 2008

For the last ten years we have devoted our time and financial resources to Open Access electronic (online) journal publication [1-3].[...]
Synthesis and Chemistry of Chiral Metallocenes
Authors: Vassylyev Oleksiy
Published: October 2008

Metallocenes are an important and well-known class of organometallic compounds, which were first discovered by Kealy and Paulson in 1951.[...]
Enantioselective Hydrogenations with Chiral Titanocenes
Authors: Vassylyev O. , Panarello A. , Khinast J.
Published: October 2008

In this review article chiral titanocenes and their application for the enantioselective hydrogenations of different unsaturated compounds are discussed, with a special emphasis on the kinetics and the practicality of the developed systems. The nature of enantioselectivity and the hydrogenation mechanisms are reviewed as well. Catalyst immobilization and the different immobilization techniques are examined.
Developments of Chiral Metallocenes as Polymerization Catalysts
Authors: Nakayama Yuushou , Shiono Takeshi
Published: October 2008

This review article describes developments in chiral metallocenes as polymerization catalysts focusing on C2 symmetric ansa-zirconocene complexes. Selective synthesis of rac-isomers of ansa-zirconocenes are surveyed. Isospecific polymerizations of propylene catalyzed by chiral zirconocenes are summarized. Advanced series of polymerizations by chiral metallocenes such as asymmetric polymerization and polymerization of polar monomers are also introduced.
Pd-catalyzed Synthesis of β-Biarylacryl Ferrocenes via Suzuki Cross-coupling
Authors: Song Q. , Lin R. , Yang Z. , Qi C.
Published: October 2008

Some novel β-biarylacryl ferrocene derivatives were synthesized viaPd-catalytic Suzuki cross-coupling reactions of β-(2-bromophenyl)acrylferroceneand arylboronic acids. The structures were determined with elemental analyses, IRspectra, and 1H-NMR spectra.
Synthesis and Crystal Structure of a New Triosmium Alkylidyne Carbonyl Cluster Containing a Chiral Ferrocenylphosphine Ligand
Authors: Wong Wai-Yeung
Published: October 2008

The synthesis, spectroscopic characterization and X-ray crystal structure of a newchiral triosmium alkylidyne carbonyl cluster, (R,S)-[Os3(μ-H)2(CO)9{μ3-CPPh2(η5-C5H4)Fe(η5-C5H3(PPh2)CH(Me)NMe2)}] (1) are described. Compound 1 crystallizes in thenon-centrosymmetric space group P21 and its absolute configuration has been established.The structure consists of an Os3C metal core with one of the PPh2 moieties of the chiralferrocenylphosphine bonded to the apical alkylidyne carbon atom to give a zwitterioniccluster complex, reminiscent of the phosphorus yli
Synthesis and Asymmetric Mono-cyclopalladation of 1,1’-Di(α-dimethylamino)ethylferrocene
Authors: Sokolov V. , Troitskaya L. , Bondareva-Don V.
Published: October 2008

Two-step synthesis of 1,1’-di(α-dimethylamino)ethylferrocene is described in details. Cyclopalladation of this diamine involving one or two amino groups is reported and the product of asymmetric mono-cyclopalladation is fully characterized.
Reactions of Cp2MCl2 (M=Ti or Zr) with Imine-Oxime Ligands. Formation of Metallacycles
Authors: Pandey O. , Sengupta S. , Tripathi C.
Published: October 2008

The reactions of bis(cyclopentadienyl)titanium(IV)/zirconium(IV) dichloridewith a series of imine-oxime ligands (LH2), derived by condensing benzil-α-monoxime and2-phenylenediamine, 4-phenylenediamine, 4-methyl-2-phenylenediamine, 2,6-diamino-pyridine, have been studied in anhydrous tetrahydrofuran in the presence of base andmetallocycles of the [Cp2M(L)] (M=Ti or Zr) type have been isolated. Tentative structureshave been proposed for the products based on elemental analysis, electrical conductance andspectral (electronic, IR and 1H-NMR) data. Proton NMR spectra indicate that on the NMRtime scale there is rapid rotation of the cyclopentadienyl ring around the metal-ring axis at25oC. Studies were conducted to assess the growth inhibiting potential of the complexessynthesized and the ligands against various bacterial strains.
Homo-polymerization of α-Olefins and Co-polymerization of Higher α-Olefins with Ethylene in the Presence of CpTiCl2(OC6H4X-p)/MAO Catalysts (X = CH3, Cl)
Authors: Skupinski W. , Nicinski K. , Jamanek D. , Wieczorek Z.
Published: October 2008

Cyclopentadienyl-titanium complexes containing –OC6H4X ligands (X = Cl,CH3) activated with methylaluminoxane (MAO) were used in the homo-polymerizationof ethylene, propylene, 1-butene, 1-pentene, 1-butene, and 1-hexene, and also in co-polymerization of ethylene with the α-olefins mentioned. The -X substituents exhibitdifferent electron donor-acceptor properties, which is described by Hammett’s factor (σ).The chlorine atom is electron acceptor, while the methyl group is electron donor. Thesecatalysts allow the preparation of polyethylene in a good yield. Propylene in the presenceof the catalysts mentioned dimerizes and oligomerizes to trimers and tetramers at 25oCunder normal pressure. If the propylene pressure was increased to 7 atmospheres,CpTiCl2(OC6H4CH3)/MAO catalyst at 25oC gave mixtures with different contents ofpropylene dimers, trimers and tetramers. At 70oC we obtained only propylene trimer.Using the catalysts with a -OC6H4Cl ligand we obtained atactic polymers with Mw182,000 g/mol (at 25oC) and 100,000 g/mol (at 70oC). The superior activity of theCpTiCl2(OC6H4Cl)/MAO catalyst used in polymerization of propylene prompted us tocheck its activity in polymerization of higher α-olefins (1-butene, 1-pentene, 1-hexene)and in co-polymerization of these olefins with ethylene. However, when homo-polymerization was carried out in the presence of this catalyst no polymers wereobtained. Gas chromatography analysis revealed the presence of dimers. The activity ofthe CpTiCl2(OC6H4Cl)/MAO catalyst in the co-polymerization of ethylene with higher α-olefins is limited by the length of the co-monomer carbon chain. Hence, the highest catalyst activities were observed in co-polymerization of ethylene with propylene (here a lower pressure of the reagents and shorter reaction time were applied to obtain catalytic activity similar to that for other co-monomers). For other co-monomers the activity of the catalyst decreases as follows: propylene >1-butene > 1-pentene >> 1-hexene. In the case of co-polymerization of ethylene with propylene, besides an increase in catalytic activity, an increase in the average molecular weight Mw of the polymer was observed. Other co- monomers used in this study caused a decrease of molecular weight. A significant increase in molecular weight distribution (Mw/Mn) evidences a great variety of polymer chains formed during the reaction.
Catalytic Activity During Copolymerization of Ethylene and 1-Hexene via Mixed TiO2/SiO2-Supported MAO with rac-Et[Ind]2ZrCl2 Metallocene Catalyst
Authors: Jongsomjit B. , Ngamposri S. , Praserthdam P.
Published: October 2008

Activities during ethylene/1-hexene copolymerization were found to increaseusing the mixed titania/silica-supported MAO with rac-Et[Ind]2ZrCl2 metallocenecatalyst. Energy Dispersive X-ray spectorcopy (EDX) indicated that the titania wasapparently located on the outer surface of silica and acted as a spacer to anchor MAO tothe silica surface. IR spectra revealed the Si-O-Ti stretching at 980 cm-1 with low contentof titania. The presence of anchored titania resulted in less steric hindrance and lessinteraction due to supporting effect.
Immobilization of Chiral Ferrocenyl Ligands on Silica Gel and their Testing in Pd-catalyzed Allylic Substitution and Rh-catalyzed Hydrogenation
Authors: Cvengroš Ján , Toma Štefan , Žembéryová Mária , Macquarrie Duncan J.
Published: October 2008

Five different silica gels containing two chiral ferrocenyl ligands were prepared by various synthetic routes and tested in an enantioselective Pd(0)-catalyzed allylic substitution and Rh-catalyzed hydrogenation. All the prepared anchored ligands were characterized by porosimetry data, DRIFTS spectra, thermal data and AAS. The aim of the work was to compare the influence of the carrier, surface properties and immobilization strategy on the performance of the catalyst.
Supramolecular Complex Formation by β-Cyclodextrin and Ferrocenylnaphthalene Diimide-intercalated Double Stranded DNA and Improved Electrochemical Gene Detection
Authors: Sato Shinobu , Nojima Takahiko , Waki Michinori , Takenaka Shigeori
Published: October 2008

Ferrocenylnaphthalene diimide 1 can bind to double stranded DNA (dsDNA) by the threading intercalation mode and the resulting complex was stabilized further by β- cyclodextrin (CD) by forming a supramolecular complex. These complex formation processes were studied by spectroscopic, viscometric, and electrochemical means in the absence or presence of β-CD. Quantitative analysis by quartz crystal microbalance (QCM) and electrochemical experiments strongly suggested a 2:1 binding stoichiometry for β-CD to 1 threading-intercalated to the dsDNA-immobilized electrode. Owing to this supramolecular complex formation, electrochemical DNA detection based on 1 was improved considerably.
Photooxidation of Some Metallocenes in a Polymer Matrix
Authors: Mallik B.
Published: October 2008

The changes in the electronic absorption spectra (UV-Vis) of some metallocene-doped poly(methyl methacrylate) (PMMA) thin films containing chloroform molecules as impurities were studied after photoexcitation in the nitrogen atmosphere. Photoexcitations were made by monochromatic radiation (using a Xe-lamp source and a monochromator) at an interval of few nanometers in the spectral range 210-750 nm. The changes in spectra were studied as a function of photoexcitation time (duration), amount of metallocene in the film and the amount of chloroform molecules present in the film. Occurrence of photoinduced charge-transfer between some metallocenes and chloroform molecules confined in the PMMA thin films was observed, which indicated photooxidation of the metallocenes in the polymer matrix. Photoresponse in the case of ferrocene derivatives was observed to decrease with the increase in the value of para- Hammett constant for the substituent attached to the ferrocene unit and also with increasing half-wave potential for the ferrocene derivatives. Photoeffects on the metallocenes having different central metal atom were studied and it was noticed that the photoeffects on the metallocenes with "18 valence electrons", as in ferrocene and ruthenocene, favored the occurrence of photoinduced charge-transfer between the metallocene and chloroform molecules present in a PMMA film. The photooxidation of a metallocene in a PMMA thin film resulted in an enhanced photoconductivity of the polymeric film.
Role of Palladium in the Redox Electrochemistry of Ferrocene Monocarboxylic Acid Encapsulated Within ORMOSIL Networks
Authors: Pandey P. , Upadhyay B.
Published: October 2008

We report herein the effect of palladium on the redox electrochemistry of ferrocene monocarboxylic acid encapsulated within an organically modified sol-gel glass network (ORMOSIL). It has been found that amount of palladium and its geometrical distribution significantly alter the redox electrochemistry of FcMCA. The geometrical distribution of palladium has been controlled by two methods: (i) palladium is allowed to link within nanostructured network of the ORMOSIL which was subsequently availed from the reactivity of palladium chloride and trimethoxysilane; (ii) palladium powder is encapsulated together FcMCA thus allowing the presence of palladium within the nanoporous domain. The content of palladium is varied by controlling the reaction dynamics of palladium chloride and trimethoxysilane interaction. For this we initially allowed to trigger hydrolysis, condensation and poly-condensation of trimethoxysilane and dimethyldiethoxysilane in acidic medium and subsequently partially dried ORMOSIL film was allowed to interact with palladium chloride. Even with partially dried ORMOSIL derived from trimethoxysilane and dimethyldiethoxysilane undergoes rapid interaction with palladium chloride and the transparent color of ORMOSIL changed to a black colour due to the formation of palladium silicon linkage. The palladium-silicon linkage has been identified by NMR, UV-VIS and transmission electron spectroscopy. The electrochemistry of FcMCA encapsulated within such an ORMOSIL matrix has been studied. Excellent redox electrochemistry of ferrocene monocarboxylic acid having peak potential separation tending to 0 for a multilayered electrode was investigated. The palladium content has been found to affect the redox electrochemistry of ferrocene as well as electrocatalytic efficiency of new ORMOSIL material. The electroanalysis of NADH is reported. The modified electrode is very sensitive to NADH with lowest detection limit of < 1 μM.
Chemical Inventory Management Solutions from CambridgeSoft
Authors: Gupta Sunil , Frutkoff Zev
Published: October 2008

Managing a chemical inventory consists of tracking the usage, disposal, and ordering of substances that are at the heart of an enterprise’s endeavors.[...]
Studies on the Synthesis and Reactivity of Novel Benzofuran-2-yl-[3-Methyl-3-Phenylcyclobutyl] Methanones and their Antimicrobial Activity
Authors: Koca Murat , Ahmedzade Misir , Çukurovali Alaaddin , Kazaz Cavit
Published: October 2008

Preparation in excellent yields of cyclobutyl benzofuran-2-yl- and naphthofuran- 2-yl-ketones, the corresponding ketoximes and thiosemicarbazones, ether derivatives of the ketoximes and thiazoles derived from the thiosemicarbazones are described. Two of the synthesized compounds have been tested against eight different microorganisms and found to be active against some of the species studied.
Three-Component Synthesis of Polysubstituted Homoproline Analogs
Authors: Kudryavtsev K. , Irkha V.
Published: October 2008

Tetrasubstituted pyrrolidines representing analogs of homoproline weresynthesized by three-component condensation of aryl(heteroaryl)aldehydes, asparagineand N-methylmaleimide (NMM). Compounds with (1S*, 3R*, 3aS*, 6aR*)-configurationat the corresponding carbon positions of the bicyclic pyrrolidine ring could be isolated ona preparative scale.
Pechmann Reaction Promoted by Boron Trifluoride Dihydrate
Authors: Stoyanov E. , Mezger J.
Published: October 2008

The Pechmann reaction of substituted phenols 1a-e with methyl acetoacetate (2) can be activated by boron trifluoride dihydrate (3) to give the corresponding 4-methyl- coumarin derivatives 4a-e in excellent yield (98-99 %).
Structural Investigation of bis(4-Methyl-1-piperazineglyoximato)dipyridinato Cobalt(III) Chloro Dinitrate Trihydrate
Authors: Öztürk S. , Akkurt M. , Macit M. , Işık S. , Fun H.
Published: October 2008

The crystal and molecular structure of the title compound,C24H36CoN10O4·2(NO3)·3(H2O)·Cl, have been determined by X-ray analysis: Cc (No: 9),a = 17.6920(4) å, b = 11.8163(2) å, c = 16.4752(4) å, ß = 91.679(1)°, Z = 4. The Co(III)ion is six-coordinated with octahedral geometry, the pyridine rings are planar and thepiperazine rings assume chair conformations.
Regioselective Synthesis of Vinylic Derivatives of Common Monosccarides Through Their Activated Stannylene Acetal Intermediates
Authors: Namazi H. , Sharifzadeh R.
Published: October 2008

The regioselective C-2-O-acrylation and metacrylation of methyl 4,6-O-benzylidene-α-D-glucopyranoside and methyl 4,6-O-benzylidene-α-D-galactopyranosidethrough their corresponding organotin intermediates have been studied. Regioselectivitywas achived through the formation of a tin chelate of the 2,3-diols. Thus, methyl 4,6-O-benzylidene-α-D-glucopyranoside and methyl 4,6-O-benzylidene-α-D-galactopyranosidewere reacted with dibutylstannylene to give the corresponding dibutylstannylene acetalintermediates that were then reacted in a regioselective manner with acryloyl chloride ormetacryloyl chloride in the presence of triethylamine (TEA) or pyridine to give thevinylic type monomeric compounds. The monomeric products containing glucose andgalactose units from each reaction were separated by column chromatography using agradient of n-hexane and ethyl acetate as eluant. The structure of the obtained compoundswere confirmed using 1H-, 13C- and 2D NMR spectroscopy.
Highly Lipophilic Benzoxazoles with Potential Antibacterial Activity
Authors: Vinsova Jarmila , Horak Václav , Buchta Vladimir , Kaustova Jarmila
Published: October 2008

A series of lipophilic 2-substituted 5,7-di-tert-butylbenzoxazoles was prepared in average yields by the reaction of 3,5-di-tert-butyl-1,2-benzoquinone with amino acids and dipeptides bearing N-terminal glycine. Dipeptides having other N-terminal amino acids undergo oxidative deamination. 5,7-Di-tert-butylbenzoxazoles have shown activity against Mycobacterium tuberculosis and some nontuberculous strains where isoniazid has been inactive. Antifungal activity was mediocre.
An Efficient and Selective Solvent-free Oxidation of Alcohols by Shaking with Chromium Trioxide Supported on Aluminium Silicate
Authors: Huang L. , Lou J. , Zhu L. , Ping L. , Fu Y.
Published: October 2008

A selective oxidation of primary alcohols to the corresponding aldehydes by shaking with chromium trioxide supported on aluminium silicate at room temperature under solvent free conditions is reported. This new procedure can also oxidise secondary alcohols.
Chemical Constituents of Piper betle Linn. (Piperaceae) Roots
Authors: Ghosh K. , Bhattacharya T.
Published: October 2008

Column chromatography of the alcoholic extract of Piper betle roots furnished aristololactam A-II and a new phenyl propene, characterized as 4-allyl resorcinol, while the petroleum-ether extract yielded a diketosteroid, viz. stigmast-4-en-3,6-dione. All these compounds were characterized by spectroscopic means. Isolation of these compounds from this source is being reported here for the first time.
Synthesis of Steroidal Thiadiazoles from Steroidal Ketones
Authors: Mushfiq M. , Alam M. , Akhtar M.
Published: October 2008

Syntheses of steroidal heterocycles containing a five-membered N,S- heterocycle attached at the 6,7 positions of the B ring are reported. 5α-Cholestane-6-one (1), its 3β-acetoxy- (2) and 3β-chloro- (3) analogues reacted with semicarbazide and aqueous sodium acetate in refluxing ethanol to yield 5α-cholestan-6-one-semicarbazone 1a and its 3-β-acetoxy and 3β-chloro derivatives 2a and 3a, respectively. The reactions of 1a, 2a and 3a with thionyl chloride in dichloromethane at low temperature afforded the cyclized thiadiazole 4 and its 3β-acetoxy- and 3β-chloro analogues 5 and 6 in good yields.
3-Formylchromones IV. The Rearrangement of 3-Formylchromone Enamines as a Simple, Facile Route to Novel Pyrazolo[3,4-b]pyridines and the Synthetic Utility of the Latter
Authors: Lacova M. , Puchala A. , Solcanyova E. , Lac J. , Kois P. , Chovancova J. , Rasala D.
Published: October 2008

One-pot and facile preparations of 6-(2-hydroxy-5-R-benzoyl)-4-methyl-2-R1- pyrazolo[3,4-b]pyridines 4a-o are described, using the reaction of 3-formyl chromones 1 with 5-amino-1-R1-pyrazoles 2. An enamine-intermediate 2-ethyloxy-6-R-3-(3-methyl-1- phenylpyrazol-5-ylaminomethylene)chroman-4-one 3 was isolated at lower temperatures. Acyloxy-derivatives 5 of compounds 4 were obtained by acylation with acid chlorides or acid anhydrides. Coumarins 6 substituted at the 3- and 4-positions were prepared from the pyrazolo[3,4-b]pyridines 4 by condensation reactions and hydrazones 7 were formed from their reaction with 2,4-dinitrophenyl hydrazine. Reactions under microwave irradiation proceeded significantly faster and with high yields.
Synthesis of 1,3,4-Thiadiazole, 1,3,4-Thiadiazine, 1,3,6-Thiadiazepane and Quinoxaline Derivatives from Symmetrical Dithiobiureas and Thioureidoethylthiourea Derivatives
Authors: Hassan A. , Mourad A. , El-Shaieb K. , Abou-Zied A.
Published: October 2008

Reactions of N,N`-disubstituted hydrazinecarbothioamides 8a-c and substituted thioureidoethylthioureas 9a-c with 2,3,5,6-tetrachloro-1,4-benzoquinone (chloranil, 10a) and 2,3,5,6-tetrabromo-1,4-benzoquinone (bromanil, 10b) to form N,N`-disubstituted [1,3,4]thiadiazole-2,5-diamines 11a-c, 6,7-dichloro-3-substituted amino-1H-benzo[1,3,4]- thiadiazine-5,8-diones 12a-c, 2,3,7,8-tetrahalothianthrene-1,4,6,9-tetraones 13a,b, 5,6,8- trihalo-7-oxo-3,7-dihydro-2H-quinoxaline-1-carbothioic acid substituted amides 14a-c, 15a-c and 7-substituted imino-[1,3,6]thiadiazepane-3-thiones 16a-c are reported. Rationales for the observed conversions are presented.
Unsaturated Sugars: Syntheses and Applications. A Special Issue in Honour of Professor Kalpattu Kuppuswamy Balsubramanian
Authors: Sundararajan G. , Ramesh N.
Published: October 2008

Kalpattu Kuppuswamy Balsubramanian (popularly and affectionately addressed as KKB) was born on September 5th 1939, at Mylapore, Madras (now Chennai), Tamil Nadu, India, in a family gifted with tradition in the noble profession of teaching.[...]
Pyrimidine Acyclo-C-Nucleosides by Ring Transformations of 2-Formyl-L-arabinal
Authors: Bari Ahmed , Feist Holger , Michalik Manfred , Peseke Klaus
Published: October 2008

The protected 2-formyl-L-arabinal 2 reacted with thiourea and cyanamide in the presence of sodium hydride to afford via ring transformations the 5-[1R,2S-1,2- bis(benzyloxy)-3-hydroxypropyl]-1,2-dihydropyrimidines 3 and 4, respectively. Similarly, treatment of 2 with 3-amino-2H-1,2,4-triazole yielded 6-[1R,2S-1,2- bis(benzyloxy)-3-hydroxypropyl][1,2,4]-triazolo[1,5-a]pyrimidine (5).
Triisobutylaluminium (TIBAL) Promoted Rearrangement of C-glycosides
Authors: Sollogoub M. , Sinay P.
Published: October 2008

Triisobutylaluminium-promoted rearrangement of unsaturated glycosides containing electron-donating aglycons, such as C-aryl glycosides, provides direct access to highly functionalised cyclohexane derivatives.
Epoxidation and Bis-hydroxylation of C-Phenyl-∆2,3-glycopyranosides
Authors: Fakha G. , Sinou D.
Published: October 2008

Epoxidation and cis-hydroxylation of C-phenyl-∆2,3-glycopyranosides have beencarried out with a view to developing C-aryl glycoside synthesis. Epoxidation of (2,3- and (6-O-tert-butyldimethylsilyl-2,3-dideoxy-D-erythro-hex-2-enopyranosyl)benzenedideoxy-D-erythro-hex-2-enopyranosyl)benzene gave predominantly the allo-adductswhatever the configuration at the anomeric center. Epoxidation of (4,6-di-O-tert-butyl-dimethylsilyl-2,3-dideoxy-D-erythro-hex-2-enopyranosyl)benzene gave the manno- andallo-adducts in a 89:11 and 40:60 ratios for the α- and β-anomers, respectively.Hydroxylation of α-C-phenyl-∆2,3-glycopyranosides using OsO4 afforded the manno-adductonly, whatever the substituents at positions 4 and 6, whereas hydroxylation of (2,3-dideoxy-β-D-erythro-hex-2-enopyranosyl)benzene and (4,6-di-O-tert-butyldimethylsilyl-2,3-dideoxy- β-D-erythro-hex-2-enopyranosyl)benzene gave the manno- and allo-adducts in25:75 and 80:20 ratios, respectively.
Towards a Synthesis of Vigabatrin Using Glycal Chemistry
Authors: Boga S. , Aidhen J. , Aidhen I.
Published: October 2008

Application of the Ferrier rearrangement led to a novel carbohydrate based synthetic route to 4-aminohexenoic acid viz. (R) and (S)-vigabatrin. The potential of D- glucose or D-galactose as the chiral starting materials for the synthesis of (R) and (S)- vigabatrin has been explored.
Bi(OTf)3 and SiO2-Bi(OTf)3 as Effective Catalysts for the Ferrier Rearrangement#
Authors: Babu J. , Khare A. , Vankar Y.
Published: October 2008

Bi(OTf)3 and SiO2-Bi(OTf)3 are found to effectively catalyze the Ferrierrearrangement of tri-O-acetyl glycals with different alcohols providing an effective routeto 2,3-unsaturated O-glycosides with good anomeric selectivity and good to excellentyields after short reaction times.
The 5-Endo-trig Cyclization of D-Glucose Derived γ-Alkenylamines with Mercury (II) Salts: Synthesis of 1-Deoxycastanospermine and its 8a-epi-Analogue†
Authors: Dhavale D. , Jachak S.
Published: October 2008

The intramolecular aminomercuration of γ-alkenylamines 1a, 1b and 4 was shown to afford the 5-endo-trig cyclized product exclusively in good yield. The utility of pyrrolidine derivatives thus obtained from D-glucose derived γ-alkenylamines 1a and 1b was demonstrated in the synthesis of 1-deoxycastanospermine (3a) and 1-deoxy-8a-epi- castanospermine (3b).
Synthesis of Cyclophellitol Utilizing a Palladium Chloride Mediated-Ferrier-II Rearrangement
Authors: Takahashi H. , Ikegami S.
Published: October 2008

Cyclophellitol and its C3-epimer have been synthesized from5-enoglucopyranoside and 5-enomannopyranoside, respectively. The carbocyclic skeletonwas constructed through a Ferrier-II reaction meditated by PdCl2.
A New iso-Amyl Benzothiazolyl Sulfoxide as an Extractant for Palladium and the Crystal Structure of its Palladium (II) Complex
Authors: Li Yao-Wei , Gu Guo-Bang , Liu Hai-Yang , Sung Herman H. Y. , Williams Ian  D. , Chang Chi-K.
Published: October 2008

A new iso-amyl benzothiazolyl sulfoxide (ABSO) was synthesized and used inthe extraction of Pd(II) from hydrochloric acid media. Pd(II) was extracted quantitativelyfrom 0.1 M HCl with ABSO in benzene (0.5 M). Ammonia solution (2.0 M) could beused as stripping agent. ABSO and Pd(II) form a 2:1 adduct [Pd (ABSO)2Cl2] in theextraction. X-ray crystal structure determination revealed PdCl2(ABSO)2 is asquare-planar complex in which ABSO acts as a neutral unidentate ligand coordinatedwith palladium(II) via the thiazolyl N atom.
Investigation of Antioxidant Vitamins (A, E, C) and Lipid Peroxidation Levels in Rats Injected N-(1,3-Benzothiazol-2-yl)-N-(4,5-dihydro-1H-imidazol-2-yl) amine
Authors: Karatas F. , Kara H. , Servi S. , Tug T. , Erulas F. A. , Koca M.
Published: October 2008

The present study examined the influence of synthetic N-(1,3-benzothiazol-2-yl)-N-(4,5-dihydro-1H-imidazol-2-yl) amine (2-Amdz) on levels of vitamins A, E and C and malondialdehyde (MDA) in rats. A total of 30 rats, divided into two groups, were used in the study. The control group was given only a subcutaneous injection of 250 ?L 75% ethanol, every other day. The other group of rats was administered a subcutaneous injection of 2-Amdz (25 mg kg-1, dissolved in 250 ?L of 75% ethanol). Injections were continued for 16 days. After the application of 2-Amdz for 16 days, the serum levels of vitamins A, E and C and malondialdehyde (MDA) were determined by HPLC. The serum vitamin A, E, and C levels decreased significantly compared to controls (p
Simple and Efficient Synthesis of 2,7-Difunctionalized-1,8-Naphthyridines
Authors: Goswami S. , Mukherjee R. , Mukherjee R. , Jana S. , Maity A. , Adak A.
Published: October 2008

The syntheses in good yields of some new difunctionalized 1,8-naphthyridines 4, 6, 8 and 9 and a novel triethylene glycol ether-linked dinaphthyridine, 10a, along with the mononaphthyridine-linked ether alcohol 10b are described. An improved and milder method for the synthesis of 2,7-diamino-1,8-naphthyridine (14) is also reported.
Reactions of 3-Formylchromone with Active Methylene and Methyl Compounds and Some Subsequent Reactions of the Resulting Condensation Products
Authors: Gasparová R. , Lácova M.
Published: October 2008

This review presents a survey of the condensations of 3-formylchromone with various active methylene and methyl compounds, e.g. malonic or barbituric acid derivatives, five-membered heterocycles, etc. The utilisation of the condensation products for the synthesis of different heterocyclic systems, which is based on the ability of the γ-pyrone ring to be opened by the nucleophilic attack is also reviewed. Finally, the applications of microwave irradiation as an unconventional method of reaction activation in the synthesis of condensation products is described and the biological activity of some chromone derivatives is noted.