Abstract  Organic aerosols, as an important fraction of airborne particulate mass, significantly affect the environment, climate, and human health. Compared with inorganic species, characterization of individual organic compounds is much less complete and comprehensive because they number in thousands or more and are diverse in chemical structures. The source contributions of organic aerosols are far from being well understood because they can be emitted from a variety of sources as well as formed from photochemical reactions of numerous precursors. This thesis work aims to improve the characterization of polar organic compounds and source apportionment analysis of fine organic carbon (OC) in Hong Kong, which consists of two parts: (1) An improved analytical method to determine monocarboxylic acids, dicarboxylic acids, ketocarboxylic acids, and dicarbonyls collected on filter substrates has been established. These oxygenated compounds were determined as their butyl ester or butyl acetal derivatives using gas chromatography-mass spectrometry. The new method made improvements over the original Kawamura method by eliminating the water extraction and evaporation steps. Aerosol materials were directly mixed with the BF sub( 3)/BuOH derivatization agent and the extracting solvent hexane. This modification improves recoveries for both the more volatile and the less water-soluble compounds. This improved method was applied to study the abundances and sources of these oxygenated compounds in PM sub(2.5) aerosol samples collected in Hong Kong under different synoptic conditions during 2003-2005. These compounds account for on average 5.2% of OC (range: 1.4%-13.6%) on a carbon basis. Oxalic acid was the most abundant species. Six C sub(2) and C sub(3) oxygenated compounds, namely oxalic, malonic, glyoxylic, pyruvic acids, glyoxal, and methylglyoxal, dominated this suite of oxygenated compounds. More efforts are therefore suggested to focus on these small compounds in understanding the role of oxygenated compounds in aerosol chemistry and physics. By reference to tracers for the major organic aerosol sources, it is deduced that the oxygenated compounds are mainly of secondary origin and direct/indirect contribution from biomass burning could also be important. The chemical composition of these oxygenated species in PM sub(2.5) samples in Hong Kong provide useful information to further ambient and model study in the aspects of chemical formation pathways and speciated organic mass distribution. (2) Source apportionment of PM sub(2.5) organic aerosols in Hong Kong were carried out in two studies. In the first study, chemical characterization and source analysis involved samples collected on high particulate matter (PM) days (avg. PM sub( 2.5) >84 kg m super(-3)) at six general stations and one roadside station from October to December in 2003. Analysis of synoptic weather conditions identified three types of high PM episodes: local, regional transport (RT) and long-range transport (LRT). Roadside samples were discussed separately. Using chemical mass balance (CMB) model, contributions of major primary sources (vehicle exhaust, cooking, biomass burning, cigarette smoke, vegetative detritus, and coal combustion) were estimated, which indicate that vehicle exhaust was the most important primary source, followed by cooking and biomass burning. All primary sources except vegetative detritus had the highest contributions at roadside station, in line with its site characteristics. Primary sources dominated roadside and local samples (>64% of fine OC), while un-apportioned OC (i.e., the difference between measured OC and apportioned primary OC) dominated RT and LRT episodes (>60% of fine OC) and un-apportioned OC had characteristics of secondary OC. In the second study, cold front episodes during winter 2004 and 2005 were targeted to investigate the effect of cold front-related LRT on chemical characteristics and organic aerosol sources of PM sub(2.5) in Hong Kong. In comparison with days under influences of mainly local emissions or RT, cold front LRT brought more organic aerosols attributable to coal combustion and biomass burning. Both cold front episodes and RT brought in significant amount of secondary OC to Hong Kong. The relative abundances of major aerosol constituents (sulfate, nitrate, ammonium, organic matter, and elemental carbon) were similar in cold front periods and RT-dominated periods.

Abstract  The title compound was prepared via a malonic ester synthesis starting with a-chloromethylpyrazine, and ending, after an asymmetric enzymatic hydrolysis of the racemic N-acetyl- beta -2-pyrazinylalanine to the L-form of the new amino acid. The optical purity was ascertained by super(1)H-NMR analysis at 360 MHz of the diastereoisomeric dipeptides L-pyrazinylalanine-L-leucine and D-pyrazinylalanine-L-leucine. Hydrophobic, steric and electronic parameters for its side chain were also estimated. The new amino acid could be introduced in the place of phenylalanine in the enkephalin-like pentapeptide (D-alanyl super(2), leucine super(5))enkephalin, thus showing good stability towards the classical methods of peptide synthesis.

Abstract  Starting from benzofuran-2-methanal, 6-substituted benzothiazole-2-amines and malonic esters, sixteen title compounds were designed and synthesized seeking to introduce anti-TMV activity. The structures of the newly synthesized compounds were confirmed by 1H-NMR, 13C-NMR, IR spectra, and MS (HREI) analysis. The bioassays identified some of these new compounds as having moderate to good anti-TMV activity. The compounds 5i and 5m have good antiviral activity against TMV with a curative rate of 52.23% and 54.41%, respectively, at a concentration of 0.5 mg/mL.

Abstract  A series of novel pyrido[1,2-a]pyrimidine-3-carboxamide derivatives 6a-n were prepared starting from 2(1H) pyridone 1 via hydrolysis, de-carboxylation, selective O-alkylation followed by rearrangement to give pyridine-2-amine 3. Compound 3 on reaction with ethoxy methylene malonic diethyl ester (EMME) under a conventional method followed by cyclization under micro wave irradiation (MWI) conditions resulted in product 5. Compound 5 on coupling with diverse substituted aliphatic amines formed title compounds 6a-n. All the products 6a-n were screened against four human cancer cell lines and compounds 6h-k and n which showed promising anticancer activity have been identified.

Abstract    Mono- and di-esterified glycerols were synthesized by the base catalyzed reaction of glycerol with aliphatic dicarboxylic acid esters (C^sub 2^-C^sub 9^): 2,3-dihydroxy-propyl oxalate (2), 1,3 dioxalyloxy propan-2-ol (3), 1,3-dimethoxyoxalyloxy propan2-ol (5), 2,3-dihydroxy-propyl malonate (6), 2,3-dihydroxy-propyl methyl malonate (7), 2,3-dihydroxy-propyl methyl succinate (8), 1,3-dimethoxysuccinyloxy propan-2-ol (9), 2,3-dihydroxy-propyl methyl glutarate (10), 1,3-dimethoxyglutaryloxy propan-2-ol (11), 2,3-dihydroxy-propyl methyl azelate (14), and 1,3-dimethoxyazelyloxy propan-2-ol (15). Their structures were elucidated by spectrometric methods. Compounds 8, 10, 2,3-dihydroxy-propl methyl adipate (12) and 14 were found to possess surface active properties and the ability to reduce the interfacial tension between paraffin and water. [PUBLICATION ABSTRACT]

Abstract  A capillary GC and GC-MS method, employing dibutyl esters is described for determining short-chain dicarboxylic acids in rain, fog and mist samples collected in the Los Angeles area. Approximately twenty dicarboxylic acids (C sub(2)-C sub(10)) were identified in the water samples, including cis (maleic) and trans (fumaric) unsaturated, saturated, normal, branched and aromatic. Oxalic acid is the dominant acid, followed by succinic and malonic acids. The total concentrations measured are 2.9-51 mu M, 64-66 mu M and 12 mu M for rain, fog and mist samples, respectively. These diacids are probably produced by photooxidation of anthropogenic and possibly biogenic organic compounds in the atmosphere.

Abstract  super(2)H- and super(13)C-labeled precursors were used to established the pathway for the biosynthesis of the 1,3,4,6-hexanetetracarboxylic (TCA) component of methanofuran, which is found in some methanogenic bacteria. The extent and position of incorporation of label into TCA were measured from the mass spectrum of the tetramethyl ester of TCA that was prepared from methanofuran present in cells grown in the presence of labeled acetate. It is concluded that TCA is biosynthesized by the condensation of alpha -ketoglutaric acid with malonic acid to form, 1,1,2,4-butanetetracarboxylic, which is further condensed with a second molecule of malonate, in a series of reaction analogous to those observed during fatty acid biosynthesis, to form TCA.

Abstract  A new derivative of diprophylline--[2-hydroxy-3(theophylline-7-ol)] propyl ester 4-benzyloxybenzoic acid was shown to decrease the content of cholesterol and of atherogenic lipoproteins in blood serum of hyperlipidemic guinea pigs. In blood serum of rabbits the new substance studied decreased cholesterol, free fatty acids and malonic dialdehyde concentrations.

Abstract  Covering up to September 2016This review reports on natural compounds that derive from the isoxazolinone ring as well as the 3-nitropropanoic acid (3-NPA) moiety. These structural elements occur in compounds that have been identified in plants, insects, bacteria and fungi. In particular, plants belonging to the family of legumes produce such compounds. In the case of insects, isoxazolin-5-one and 3-NPA derivatives were found in leaf beetles of the subtribe Chrysomelina. A number of these natural products have been synthesized so far. In the case of the single compound 3-NPA, several synthetic strategies have been reported and some of the most efficient routes are reviewed. The toxicity of 3-NPA results from its ability to bind covalently to the catalytic center of succinate dehydrogenase causing irreversible inhibition of mitochondrial respiration. As a motif that is produced by many species of plants, leaf beetles and fungi, different detoxification mechanisms for 3-NPA have evolved in different species. These mechanisms are based on amide formation of 3-NPA with amino acids, reduction to β-alanine, ester formation or oxidation to malonic acid semialdehyde. The biosynthetic pathways of 3-NPA and isoxazolin-5-one moieties have been studied in fungi, plants and leaf beetles. In the case of fungi, 3-NPA derives from aspartate, while leaf beetles use essential amino acids such as valine as ultimate precursors. In the case of plants, it is supposed that malonate serves as a precursor of 3-NPA, as indicated by feeding of 14C-labeled precursors to Indigofera spicata. In other leguminous plants it is suggested that asparagine is incorporated into compounds that derive from isoxazolin-5-one, which was indicated by 14C-labeled compounds as well. In the case of leaf beetles it was demonstrated that detection of radioactivity after 14C-labeling from a few precursors is not sufficient to unravel biosynthetic pathways.

Abstract  Chebulic ellagitannins (ChET) are plant-derived polyphenols containing chebulic acid subunits, possessing a wide spectrum of biological activities that might contribute to health benefits in humans. The herbal formulation Padma Hepaten containing ChETs as the main phenolics, is used as a hepatoprotective remedy. In the present study, an in vitro dynamic model simulating gastrointestinal digestion, including dialysability, was applied to estimate the bioaccessibility of the main phenolics of Padma Hepaten. Results indicated that phenolic release was mainly achieved during the gastric phase (recovery 59.38%-97.04%), with a slight further release during intestinal digestion. Dialysis experiments showed that dialysable phenolics were 64.11% and 22.93%-26.05% of their native concentrations, respectively, for gallic acid/simple gallate esters and ellagitanins/ellagic acid, in contrast to 20.67% and 28.37%-55.35% for the same groups in the non-dialyzed part of the intestinal media. Investigation of human gut microbiota metabolites of Padma Hepaten and pure ChETs (chebulinic, chebulagic acids) established the formation of bioactive urolithins (A, B, C, D, M5). The fact of urolithin formation during microbial transformation from ChETs and ChET-containing plant material was revealed for the first time. Evaluation of the protective effect of ChETs colonic metabolites and urolithins on tert-butyl hydroperoxide (t-BHP)-induced oxidative injury in cultured rat primary hepatocytes demonstrated their significant reversion of the t-BHP-induced cell cytotoxicity, malonic dialdehyde production and lactate dehydrogenase leakage. The most potent compound was urolithin C with close values of hepatoprotection to gallic acid. The data obtained indicate that in the case of Padma Hepaten, we speculate that urolithins have the potential to play a role in the hepatic prevention against oxidative damage.

Abstract  The main objective of this study was to determine the phytochemical composition in the leaves of Coriandrum sativum, using methanolic extraction and report the main functional components by using IR technique. The phytochemical compounds in the extract were then screened by GC-MS method. Seven bioactive phytochemical compounds were identified in the methanolic extract of C. sativum: 1,6-octadien-3-ol, 3,7-dimethyl, 1,6-octadien-3-ol,3,7-dimethyl, 2-aminobenzoate, bicyclo[2.2.1]heptan-2-one,1,7,7-trimethyl., geranyl vinyl ether, 9,10-secocholesta-5,7,10(19)-triene-3,24,25-triol., ascorbic acid 2,6-dihexadecanoate and 7aH-cyclopenta[a] cyclopropa[f]cycloundecene. Thirteen bioactive phytochemical compounds were identified in the methanolic extract of Melia azedarach. In the present investigation, a variety of compounds have been detected in M. azedarach including trichloromethane, propanedioic acid, diethyl ester, 2-pyrrolidinyl-methylamine, butanedioic acid, diethyl ester, 2-piperidimethanamine, butanedioic acid, hydroxyl-, diethyl ester, 2,5-dimethylhexane-2,5-dihydroperoxide, dithiocarbamate, s-methyl-,n-(2-methyl-3-oxobutyl), triethyl citrate, y-sitosterol, ethyl 9,12,15-octadecatrienoate, hexadecanoic acid, 2-hydroxy-1-(hydroxymethyl)ethyl ester, and octadecane, 3-ethyl-5-(2-ethylbutyl). It contains chemical constitutions which may be useful for various herbal formulation as anti-inflammatory, analgesic, antipyretic, cardiac tonic and antiasthamatic. C. sativum is highly active against Aspergillus terreus 6.01 plus or minus 0.200. Bioactive compounds of C. sativum and M. azedarach were assayed for in vitro antibacterial activity against Staphylococcus aureus, Proteus mirabilis, Pseudomonas aerogenosa, Escherichia coli and Klebsiella pneumonia using the diffusion method in agar. The zone of inhibition was compared with different standard antibiotics. The diameters of inhibition zones ranged from 5.60 plus or minus 0.320 to 1.96 plus or minus 0.200 mm for all treatments.

Abstract  1. The metabolism and disposition of ethyl 3-ethoxypropionate (EEP) in male Sprague-Dawley rats was studied following single oral gavage at 150 or 1500 mg/kg. The 14C-EEP was rapidly absorbed at both dose levels, and was excreted predominantly as metabolites in the urine within 24 h of administration. 2. The major urinary metabolites of EEP were monoethyl malonate and 3-ethoxypropionate. Other metabolites included malonic acid and the glycine conjugate of 3-ethoxypropionate. Trace amounts of 14C-EEP were detected after both doses. 3. 14CO2 in the expired air accounted for 34% and 20% of the dose at 150 and 1500 mg 14C-EEP/kg, respectively, mostly in the first 24 h following administration. The appearance of 14CO2 indicates extensive oxidation of the molecule, and the lower percentage of 14CO2 at the high dose possibly indicates saturation of an oxidative metabolic pathway. 4. No evidence was found for alkoxyacetic acid metabolites, such as those produced by metabolism of some low molecular weight ethylene glycol ethers.

Abstract  A series of lower rim-functionalised calix[4]arenes bearing 1,3-positioned phosphorus(III) ligands L-1-L-9 have been synthesized and their coordinative properties examined. L-1 and L-2 {5,11,17,23-tetra-tert-butyl-25,27-bis[2-(diphenylphosphino)ethoxy]- and -25,27-bis(diphenylphosphinomethoxy)-26,28-bis(3-oxabutyloxy)calix[4]arene} react with [Rh(nbd)(THF)(2)]BF4 (nbd=1,5-norbornadiene; THF=tetrahydrofuran) to afford in high yield the complexes [Rh(nbd)L-1]BF4 and [Rh(nbd)L-2]BF4, respectively, where the calixarene behaves as a P,P' chelator. Both complexes catalyse hydroformylation of styrene at comparable rates, the linear:branched aldehyde ratio being 5:95. The presence of the ether side groups did not exert a noticeable effect on the selectivity nor the catalytic activity. Reaction of L-1-L-8 with [Pd(eta (3)-C3H4Me)(THF)(2)]BF4 gave the corresponding cationic chelate complexes [Pd(eta (3)-C3H4Me)L-i]BF4 that are active in the catalytic alkylation of 1,3-diphenylprop-2-enyl acetate with dimethyl malonate. Owing to the presence of a non-planar Pd-allyl fragment, the achiral calixarene subunits of some of these complexes are no longer C-2v-symmetrical, as evidenced by the H-1 and C-13 NMR spectra that show non-equivalent side groups. Selective chelation via the two phosphorus atoms was also observed in the complexes [RuCl(p-MeC6H4Pri)L-i]BF4 (L-i=L-3 or L-4) obtained by reaction of the amide phosphines L-i with [RuCl(p-MeC6H4Pri)(THF)(2)]BF4 [L-3=5,11,17,23-tetra-tert-butyl-25,27-bis(diethylcarbamoylmethoxy)-26,28-bis(diphenylphosphinomethoxy)- and L-4=5,11,17,23-tetra-tert-butyl-25,27-bis(diphenylphosphinomethoxy)-26,28-bis{(1-(R)-phenylethyl)carbamoylmethoxy}-calix[4]arene]. Reaction of L-3 or L-4 with neutral [RuCl2(p-MeC6H4Pri)](2) afforded the bimetallic complexes [{RuCl(p-MeC6H4Pri)}(2)L-i] where the calixarene acts as a P,P' bridging ligand. Reaction of AgBF4 with calix-crown L-9 {25,27-bis(diethoxyphosphinoxy)-26,28-(3,6,9-trioxaundecane-1,11-dioxy)calix[4]arene} resulted in quantitative formation of the complex [AgL9]BF4 in which the silver(I) ion lies inside the cavity constituted by the crown ether fragment and the two phosphorus arms. As revealed by a single crystal X-ray diffraction study, the Ag+ ion has a trigonal P2O coordination environment with a P-Ag-P angle of 134.74(4)degrees.

Abstract  New basic zeolite catalysts obtained by grafting amino groups onto NaX and CsNaX zeolites exhibit excellent catalytic activities for Knoevenagel condensation reaction between benzaldehyde and ethyl cyanoacetate, (ECA), ethyl acetoacetate (EAA) and diethyl malonate (DEM). The CsNaX-NH2 catalyst also displays higher conversion compared to aminopropylated MCM-41. Knoevenagel condensation reaction in a CsNaX zeolite microreactor performed better than the traditional packed bed reactor (PBR) with an order of magnitude higher productivity (i.e. moles ethyl 2-cyano-3 phenylacrylate produced per hour for each gram catalyst). A nearly fourfold increase in reaction conversion was obtained for the microreactor when CsNaX-NH2 Catalyst was used. A membrane microreactor was obtained by incorporating a water-selective, NaA membrane to the multi-channel microreactor. The selective removal of water byproduct during the reaction led to a 25% improvement in reaction conversion for both catalysts. (C) 2003 Elsevier B.V. All rights reserved.

Abstract  The aggregation induced emission (AIE) behavior shown by organic chromophores is very interesting for the development of efficient solid state devices. The restriction of intramolecular rotation is by far the most frequently assumed mechanism to explain this behavior; by blocking or reducing this rotation, upon rigidification of the environment, molecular luminescence is restored. By means of ultrafast pump-probe spectroscopy combined with density functional theory (DFT) and time-dependent DFT calculations, we show direct evidence of intramolecular rotation in a simple push-pull organic chromophore,4-diethylamino-2 benzylidene malonic acid dimethyl ester, possessing AIE properties. The spectral evolution of the stimulated emission band of the chromophore in the first 45 ps after photoexcitation is fully consistent with the presence of a torsional relaxation toward the equilibrium geometry of the excited state, taking place on time scales that depend on the solvent viscosity. The structural features of the excited state fully account for the different photoluminescence efficiencies observed in solvents with different viscosities.

Abstract  Complexes of diethylmalonate, a common building block in organic synthesis, with gold(l) and silver(l) have been investigated. Both metal cations coordinate between the two carbonyl-oxygen atoms of diethylmalonate. The gold(I) complex should also bear diethylmalonate in the enol-form in the gas phase, while the diketo form is preferred in the condensed phase. The IRMPD spectrum shows that the diketo form is retained upon electrospray ionization also in the gaseous diethylmalonate complex with Au(PMe3)(+). The diethylmalonate complex with a bare silver cation undergoes an association with a water molecule in the gas phase. Spectra of the bare complex and the water-tagged complex are compared. (C) 2012 Elsevier B.V. All rights reserved.

Abstract  Highly enantioselective (up to >99% eel palladium-catalyzed substitution of rac-3-diphenyl-2-propenyl acetate with dimethyl malonate as nucleophile was achieved using 2-(1-hydroxyalkyl)-6-(4,5-dihydro-2-oxazolyl)pyridines and 2-(1-alkoxyalkyl)-6-(4,5-dihydro-2-oxazolyl)pyridines as ligands for palladium. The selectivity was found to be highly dependent on the nature of the substituents on the ligand and on the relative configuration of the two stereogenic centers present in the ligand. The results are discussed in terms of the conformation of the ligands in the intermediate pi-allylpalladium complexes.

Abstract  Allylic nucleophilic substitution of trifluoromethyl-group substituted cinnamyl carbonate with diethyl malonate anion in the presence of palladium complex catalyst gave regio- and stereo selectively the S(N)2' product. The regiochemistry caused by the polar effect of trifluoromethyl group was opposite to the methylated cinnamyl substrate in a similar steric environment. The sterically more hindered mesityl and tert-butyl substrates than phenyl derivative also gave the products reacted at the more hindered sites. Although o-substituted substrates expecting intramolecular coordination to affect regiochemistry were examined, no alternative regioisomers were detected. (C) 2003 Elsevier Science B.V. All rights reserved.

Abstract  Our recent reports on the synthesis of Sn-incorporated mesoporous SBA-15 materials have been reviewed. The preparation of the samples with different Si/Sn ratios followed two procedures, the first is the post-synthesis modification of SBA-15 by impregnation with Sn chloride or acetate, and the second is the direct method in which Sn chloride was introduced in to Si precursor along with amphiphilic triblock copolymer, while varying the ratio of the synthesis gel. Detailed characterization of the Sn-SBA-15 samples by a variety of techniques shows how the synthesis procedures influence the properties of the samples that reflect on the differences in (a) the structural features, (b) morphology and textural properties, such as the pore characteristics, (c) the possible location of Sn4+ ions in the meso silica structure and their reducibility, (d) the nature of the Sn species and their the coordination sphere and (e) the acid-base characteristics. We developed a possible model for the localization of Sn species in SBA-15 pore structure for different conditions of preparation. This report includes our investigations on the catalytic properties of these Sn-SBA-15 samples in 3 industrially important reactions, viz., trans-esterification of diethyl malonate, synthesis of nopol by Prins condensation of beta-pinene with para-formaldehyde and the epoxidation of norbornene. In each of this reaction, while demonstrating the catalytic role of Sn species, we show that the requirement of the type and the environment of Sn species are different for these reactions.

Abstract  Novel 1,3-dimesityl-4,5,6,7-tetrahydro-[1,3]-diazepin-2-ylidene-coordinated Ru-alkylidene complexes RuCl(2)(1,3-dimesityl-4,5,6,7-tetrahydro-1,3-diazepin-2-ylidene)(CH-2-(2-PrO)C(6)H(4)) (2) and Ru(CF(3)COO)(2) (1,3-dimesityl-4,5,6,7-tetrahydro-1,3-diazepin-2-ylidene)(=CH-2-(2-PrO)C(6)H(4)) (3) were synthesized from the first-generation Grubbs-Hoveyda catalyst, [RUCl(2)(PCy(3))(=CH-2-(2-PrO)C(6)H(4))] (1). The single-crystal X-ray structure of 3 was determined. Compound 2 showed excellent reactivity in ring-opening metathesis polymerization (ROMP) of cis-cycloocta-1,5-diene (COD), yielding polymers with a high trans-content of 80%. Compound 3 is also an active initiator for ROMP; however, a low trans-content of only 14% was found for poly-COD prepared by this initiator. Both 2 and 3 turned out to be good catalysts for cross-metathesis (CM), while both compounds showed only moderate activity in ring-closing rnetathesis (RCM). Finally, 3 is also a good polymerization catalyst for the regioselective cyclopolymerization of dipropargyl diethyl malonate (DEDPM), resulting in poly-DEDPM virtually solely based on five-membered repeat units.

Abstract  Two novel supramolecular complexes-of types [Ru(L)(H2L)Cl.OH2] and [Ru(HLn)Cl-3] (where H2L is a potential tetradentate ligand derived from hydrazine hydrate and diethyl malonate, and HLn is a potential bidentate ligand derived from coupling of allyl azo-beta-diketone) have been synthesized and characterized by elemental analysis, conductance and magnetic measurements, followed by H-1 NMR, to determine the effect of substituents on the intramolecular hydrogen bond. The electronic properties and models of the bonding of ligands and complexes were investigated by UV-Vis and IR spectroscopies. The first type of complex contains terminal hydrazinic nitrogen atoms with an unshared electron pair and may take part in nucleophilic condensations. Therefore, the reactions of allyl-beta-diketone complexes with malonic dihydrazide have also been studied, as these cause ring closure and formation of supramolecular macrocyclic ligand complexes. The wavelengths of the principal electronic absorption peaks have been accounted for quantitatively in terms of crystal field theory, and various parameters have been evaluated. On the basis of the electronic spectra, an octahedral geometry has been established for the polymer complexes C. The macrocyclic polymer complexes D are pentacoordinate, and a trigonal-bipyramidal environment (D-3h) is suggested for the ruthenium(III) ion. The effect of the Hammett constant on the ligand field parameters is also discussed. Copyright (C) 2004 John Wiley Sons, Ltd.

Abstract  An environmentally benign, solventless, rapid and economic technique for the synthesis of substituted quinolines, indoles and aromatic compounds using Knoevenagel condensation is described from readily available aromatic and heterocyclic aldehydes and diethyl malonate on solid inorganic support under microwave irradiation (MWI). The method is devoid of the hazards of solution phase reactions. All the compounds are screened for their antifungal activity.

Abstract  New chiral P,N-hybrid aryl phosphites have been obtained by one-step phosphorylation of amino and imino alcohols. Complexation of the new ligands with [Rh(CO)(2)Cl](2), [Pd(COD)Cl-2] and [Pd(allyl)Cl](2) was found to give chelate complexes [Rh(CO)Cl(eta(2)-(PN)-N-boolean AND)], [PdCl2(eta(2)-(PN)-N-boolean AND)] and [Pd(allyl) (eta(2)-(PN)-N-boolean AND)]Cl-+(-), respectively. With these new P,N-ligands, up to 82% ee enantioselectivity was achieved in the Pd-catalysed alkylation of ethyl 3-penten-2-yl carbonate with dimethyl malonate, up to 80% ee in the Pd-catalysed sulfonylation of methyl 3-penten-2-yl carbonate with sodium p-toluenesulfinate, and up to 50% ee in the Rh-catalysed hydrosilylation of acetophenone with diphenylsilane. ((C) Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002).

Abstract  New bicyclic (1) and tricyclic (2a) hydrophosphoranes have been synthesized from iso-leucinol. Complexation of bicyclic hydrophosphorane 1 with [PdCl2(COD)], [PdCl2(RCN)(2)] and [Pd(allyl)Cl](2) has been found to give chelate products [PdCl2(L)] and [Pd(allyl)(L)]Cl-+(-) containing an "open" form of the phosphorane. Tricyclic hydrophosphorane 2a, as well as its homologue 2b, forms metal complexes with P-monodentate binding of a hydrophosphorane, phosphoranide or "open" form of the ligand. Up to 74% ee has been achieved in the Pd-catalyzed alkylation of 1,3-diphenylallyl acetate with dimethyl malonate using 1 and 2a and 2b as chiral ligands. (C) 2002 Elsevier Science B.V. All rights reserved.

Abstract  3-(4-Oxo-5,6,7,8-tetrahydro-4H-benzo[4,5]thieno[2,3-d][1,3]oxazin-2-yl)propanoic acid and its ethyl ester 6ab have been prepared via succinoylation of ethyl 2-amino-4,5,6,7-tetrahydrobenzo[b]thlophene-3-carboxylate 1, followed by ester hydrolysis, selective esterification, and acetic anhydride induced cyclization of the thiophenecarboxylic acid derivatives 3, 5. Reaction of 1 with diethyl malonate gave the malonic acid diamide 7, which on ester hydrolysis followed by acetic anhydride induced water elimination furnished the 2-substituted 4H-benzo[4,5]thieno[2,3-d][1,3]oxazine derivative 10 in high yield. A series of new benzo[4,5]thieno[2,3-d]pyrimidines 11-19, which bear a propanoic acid substituent in the 2-position and an amino, aryl, aminosugar, and arylmethylideneamino-substituents in the 3-position have been prepared via the reaction of 6ab with hydrazine hydrate or aromatic amines followed by treatment with aromatic aldehydes, isatin, or aldoses. The aldimines 18a-d underwent unprecedented acid catalyzed tandem cyclization-transannular aldehyde extrusion into octalzydro-1H-benzo[4'.5']thieno[2'.3'.4,5]pyrimido[1,2-b]pyridazines 21. Two other unequivocal approaches for 21 also have been explored, either by treatment of the amino acid derivative 11 with thionyl chloride or by thermal cyclization of the amino ester derivative 12.