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The histone deacetylases (HDACs) are being explored as a promising therapeutic target for the treatment of various diseases. Here, the synthesis of a series of pyrimidine‐based 1,3,4‐oxadiazoles, in which the oxadiazole scaffold is attached to the pyrimidine ring via a methyleneoxy spacer, is described and their HDAC inhibitory activity studied. The target compounds were synthesized by sequence of reactions involving O‐alkylation of 2‐(methylthio)pyrimidin‐4(3H)‐ones with ethyl 2‐bromoethanoate followed by oxidation of the 2‐methylthio group, displacement of the obtained 2‐methylsulfonyl group with amines, hydrazinolysis of the obtained ethyl (2‐amino‐substituted pyrimidin‐4‐yloxy)acetates to give the corresponding hydrazides and their cyclization under the treatment with ethyl O‐ethyl xanthate or carbonyldiimidazole to 1,3,4‐oxadiazole‐2(3H)‐thiones and 1,3,4‐oxadiazol‐2(3H)‐one, correspondingly. In addition, two 1,3,4‐oxadiazole‐2(3H)‐thiones were converted into (N3)‐morpholinomethyl derivatives by the Mannich reaction with formaldehyde and morpholine. The yields of intermediates and target compounds ranged from moderate to excellent. The synthesized compounds were characterized by 1H and 13C NMR spectra and HRMS data, their purity was controlled by TLC. The synthesized pyrimidine‐based 1,3,4‐oxadiazoles (18 compounds) were tested as inhibitors of the HDAC4 and HDAC8 isoforms and their inhibitory activity was compared with that of Vorinostat. Most of the oxadiazolethiones containing methyl group at the position 6 of the pyrimidine moiety were found to be more selective towards HDAC8, while oxadiazolethiones with propyl group in the pyrimidine ring were active against HDAC4. Among the tested compounds, 5‐((2‐(dibutylamino)‐6‐propylpyrimidin‐4‐yloxy)methyl)‐1,3,4‐oxadiazole‐2(3H)‐thione (48) was found to have the strongest inhibitory activity for HDAC4 isoform (IC50 = 4.2 μM vs. IC50 = 59 μM for Vorinostat) while 5‐((2‐(cyclopentylamino)‐6‐propylpyrimidin‐4‐yloxy)methyl)‐1,3,4‐oxadiazole‐2(3H)‐thione (50) was the most potent HDAC8 inhibitor (IC50 = 6.8 μM). [ABSTRACT FROM AUTHOR]

N-((2-chloropyridin-3-yl)carbamothioyl)thiophene-2-carboxamide (HL1), N-((6-methylpyridin-2-yl)carbamothioyl)thiophene-2-carboxamide (HL2), N-(allylcarbamothioyl)thiophene-2-carboxamide (HL3), 2-chloro-N-(methyl(1-phenylethyl)carbamothioyl)benzamide (HL4) and 2-chloro-N-(bis((R)-1-phenylethyl)carbamothioyl)benzamide (HL5) were synthesized and characterized via FT-IR, 1H-NMR, 13C-NMR and HR-MS techniques and HL3 was characterized via a single crystal X-ray diffraction experiment. The antituberculosis activity of the synthesized thiourea derivatives was tested against the H37RV (ATCC27294), ATCC35822 (INH resistant), ATCC35838 (RIF resistant), ATCC35820 (STM resistant) and ATCC35837 (EMB resistant) standard bacteria strains. The thiourea derivatives were tested on two MDR and one primary drug-sensitive isolates with the microplate nitrate reductase test method. The results indicated that HL2 and HL3 had tuberculosis activity on some of the isolates. It was observed that HL4 was the most effective among all the thiourea derivatives. The interaction mechanism of the synthesized compounds on 2X23, a tuberculosis protein, was investigated via molecular docking method. The interaction was observed to occur over S and Cl atoms in all the compounds. The compounds containing the methyl group were observed to interact via this group. [ABSTRACT FROM AUTHOR]

The development of hybrid molecules with significant human therapeutic properties is one of the main approaches of pharmaceutical research. One of the most important pharmacophores is the quinazolin-4(3H)-one heterocycle moiety, due to its wide range of biological activities. By its derivatization with polyphenolic compounds, in our previous research, it proved to possess a good antiradical activity of ortho-diphenolic derivatives of quinazolin-4(3H)-one. In this study, we developed two new series of compounds, with an additional phenolic group or with a methyl group on the thioacetohydrazone fragment. The methods used to evaluate the activity of the compounds were radical scavenging, reduction of oxidizing reagents and transition metals' ions chelation assays. Quantum descriptors were also calculated in order to evaluate the influence of substituents and their position on the activity of the compounds. The cytotoxic activity was evaluated using normal human foreskin fibroblast cells (BJ) and two cancerous cell lines, lung adenocarcinoma cells (A549) and prostate carcinoma cells (LNCaP). The results obtained for the pyrogallol derivatives showed a high antioxidant activity compared to ascorbic acid and Trolox. All the synthesized compounds displayed a higher cytotoxicity against the cancerous cell types and a high cytocompatibility with the normal cells. The antioxidant activity was deeply influenced by the addition of the third phenolic group in the synthesized molecules. [ABSTRACT FROM AUTHOR]

A structure-guided modelling approach using COX-2 as a template was used to investigate the effect of replacing the chloro atom located at the chlorophenyl ring of amide-linked bipyrazole moieties, aiming at attaining better anti-inflammatory effect with a good safety profile. Bromo, fluoro, nitro, and methyl groups were revealed to be ideal candidates. Consequently, new bipyrazole derivatives were synthesised. The in vitro inhibitory COX-1/COX-2 activity of the synthesised compounds exhibited promising selectivity. The fluoro and methyl derivatives were the most active candidates. The in vivo formalin-induced paw edoema model confirmed the anti-inflammatory activity of the synthesised compounds. All the tested derivatives had a good ulcerogenic safety profile except for the methyl substituted compound. In silico molecular dynamics simulations of the fluoro and methyl poses complexed with COX-2 for 50 ns indicated stable binding to COX-2. Generally, our approach delivers a fruitful matrix for the development of further amide-linked bipyrazole anti-inflammatory candidates. [ABSTRACT FROM AUTHOR]

Brassinolide (BL) is a possible plant growth regulator in agriculture, but the presence of a steroid skeleton hampers the field application of BL in agriculture because of its high synthetic cost. We discovered NSBR1 as the first nonsteroidal BL-like compound using in silico technology. Searching for more potent BL-like compounds, we modified the structure of NSBR1 with respect to 2 benzene rings and the piperazine ring. The activity of synthesized compounds was measured in Arabidopsis hypocotyl elongation. The propyl group of butyryl moiety of NSBR1 was changed to various alkyl groups, such as straight, branched, and cyclic alkyl chains. Another substituent, F, at the ortho position of the B ring toward the piperazine ring was changed to other substituents. A methyl group was introduced to the piperazine ring. Most of the newly synthesized compounds with the 3,4- (OH)2 group at the A ring significantly elongated the hypocotyl of Arabidopsis. [ABSTRACT FROM AUTHOR]

Novel 1,2,3-triazole-tethered N-norbuprenorphine derivatives with an OMe or OH group at the C3 position were synthesized alongside with evaluation of their analgesic properties. The analgesic activities of the resulting library were investigated via tail flick test in mice. Our results indicated that 10b and 10e were as effective as the starting compounds 8 and 9 with ED50 equal to 16.59 and 19.44 mg/kg, respectively. To investigate the effect of a methyl group at C3 on biological properties, the most active compounds were O-demethylated and their anti-nociceptive effects were assessed. The new O-demethylated derivatives (11b and 11e) showed better analgesic properties than the parent compounds with ED50 of 14.73 and 15.80 mg/kg, respectively. Naloxone prevented the analgesic effect of the synthesized compounds, indicating that the opioid receptors are highly involved in the anti-nociceptive effects. The potential dependency effects of the most potent derivatives were studied by condition place preference test in mice and compared with morphine and buprenorphine. Interestingly, 10b, 10e, 11b, and 11e did not show any dependency effect, similar to buprenorphine. [ABSTRACT FROM AUTHOR]

Background. Endolysins of a number of bacteriophages, including coliphages T5, RB43, and RB49, target the peptidoglycans of the bacterial cell wall. The backbone of these bacterial peptidoglycans consist of alternating N-acetylglucosamine and N-acetylmuramic acid residues that is further "reinforced" by the peptide subunits. Because of the mesh-like structure and insolubility of peptidoglycans, the processes of the peptidoglycan binding and hydrolysis by enzymes cannot be studied by spectral methods. To overcome these issues we synthesized and analyzed here one of the simplest water soluble peptidoglycan mimetics. Methods. A compound has been synthesized that mimics the peptidoglycan fragment of the bacterial cell wall, N-acetylglucosaminyl-β(1-4)-N-acetylmuramoyl-l-alanyl-γ-d-glutamyl-l-alanyl-d-alanine. NMR was used to study the degradation of this peptidoglycan mimetic by lytic l-alanoyl-d-glutamate peptidases of colibacteriophages T5, RB43, and RB49 (EndoT5, EndoRB43, and EndoRB49, respectively). Results. The resulting glycopeptide mimetic was shown to interact with the studied enzymes. Its hydrolysis occurred through the bond between l-Ala and d-Glu. This artificial substrate mimetic was hydrolyzed by enzymes at different rates, which decreased outside the pH optimum. The EndoT5 demonstrated the lowest hydrolysis rate, whereas the EndoRB49-driven hydrolysis was the fastest one, and EndoRB43 displayed an intermediate potency. These observations are consistent with the hypothesis that EndoRB49 is characterized by the lowest selectivity, and hence the potentially broader spectrum of the peptidoglycan types subjected to hydrolysis, which was put forward in the previous study. We also show that to hydrolyze this glycopeptide mimetic, enzymes approach the glycopeptide near the methyl groups of all three alanines. [ABSTRACT FROM AUTHOR]

The hydrosilylation reactions of allylgermanes R3GeAll (R3 = Cl3, Me3) in the presence of a platinum catalyst (Karstedt catalyst) with methylchlorohydridesilanes MenCl3–nSiH (n = 0–2) and 1,1,3,3-tetramethyldisiloxane have been studied. It was found that only 1,3-adducts are formed. In some cases, the replacement of only one methyl group at silicon with Cl (or vice versa, Cl for methyl group) leads not only to a decrease in the yields of the products obtained, but to a complete absence of reaction. A possible route of the studied reactions is proposed. The identification of the synthesized compounds was carried out using the methods of gas-liquid chromatography, 1H NMR spectroscopy and chromatography-mass spectrometry. [ABSTRACT FROM AUTHOR]

3aα-H-4α-(3′-Propionic acid)-5α-hydroxy-7aβ-methylhexahydro-1-indanone-δ-lactone (sitolactone, or HIL) and 3aα-H-4α-(3′-propionic acid)-7aβ-methylhexahydro-1,5-indanedione (HIP) are important intermediates for the synthesis of a variety of steroidal medicines with an α-methyl group or without the methyl group at the C10-position. Although they can be prepared by chemical synthesis or microbial transformation of steroids, their low efficiency and the formation of by-products limit their application. In this study, by investigating the degradation pathway of steroidal C/D rings and analyzing the metabolites in the catabolism of phytosterols by the genetically modified strains ΔfadD3 and ΔfadE30 of Mycobacterium fortuitum (ATCC 6841), two carboxylic acid reductase genes (car1 and car2) were identified to be involved in the degradation of HIP. The inactivation of these two car genes in strains ΔfadD3 or ΔfadE30 blocked the generation of other metabolites and enhanced the accumulation of HIP or HIL, respectively. At the preparative scale, the recombinant strains transformed phytosterols into HIP or HIL at 20 g L−1 substrate concentration in 88% or 75% yields, respectively, without detectable by-products. This offers an economically feasible and green process for the industrial production of these important intermediates from bio-renewable phytosterols, cheap and abundant by-products of the plant oil industry. [ABSTRACT FROM AUTHOR]

In this study, the novel 5-Mercapto-2-(5-methyl-furan-2-yl-methylidenamino)-1,3,4-thiadiazole molecule was synthesized from the reaction of 2-amino-5-mercapto-1,3,4-thiadiazole with 5-methyl-furan-2-carbaldehyde. The 5-Mercapto-2-(5-methyl-furan-2-yl-methylidenamino)-1,3,4-thiadiazole was optimized by using DFT(B3LYP)-HF methods. The mulliken charges, HOMO-LUMO energy, ELUMO-EHOMO energy gap (ΔEg), dipole moments, electron affinity (A), ionization potential (I), chemical softness (σ), chemical hardness (η), electronegativity (χ), bond angles, total energy and bond lengths of the molecule were calculated by using 6-31G(d,p) basis set with DFT (B3LYP) and HF methods. Otherwise, the 1H-NMR and 13C-NMR isotropic shift values were calculated by using GIAO methods with GaussianG09W package program. The experimental/theoretical values were compared and the regression analysis were found. Defining IR values were used the veda4f program. The theoretical infrared spectrums are visualised. [ABSTRACT FROM AUTHOR]

Fenestranes, a specific class of natural products, contain four fused rings that share a central quaternary carbon atom. The fungal natural product penifulvin A (1) is a potent insecticidal sesquiterpene that features the [5.5.5.6]dioxafenestrane ring. Although the chemical synthesis of 1 has been achieved recently, the enzymes catalysing the cyclization and oxidation of FPP to 1 remain unknown. In this work, we identified a concise pathway that uses only three enzymes to produce 1. A new sesquiterpene cyclase (PeniA) generates the angular triquinane scaffold silphinene (6). A cytochrome P450 (PeniB) and a flavin‐dependent monooxygenase (PeniC) catalyse a series of oxidation reactions to transform 6 into 1, including oxidation of the C15 methyl group to a carboxylate moiety, oxidative coupling of the C15 carboxylate and the C1‐C2 olefin to form a γ‐lactone, and Baeyer–Villiger oxidation to form a δ‐lactone. Our results demonstrate the highly concise and efficient ways in which fungal biosynthetic pathways can generate complex sesquiterpene scaffolds. [ABSTRACT FROM AUTHOR]

Abstract A new set of mesoionic 1,2,3-triazolium salts functionalised by para substituted phenoxymethyl side groups were prepared using the 'click' Cu catalyzed [3 + 2] cycloaddition of organic azides and terminal alkynes. Four previously unreported neutral triazoles (1–4) were first isolated en route to formation of the salts (5–8). All the compounds were fully characterised (1H, 13C NMR; IR; HR-MS; EA) and representative neutral triazoles and salts were structurally characterised by single crystal X-ray diffraction (SCXRD). Full examination of structural characteristics of the neutral compounds and the salts were presented by detailed analysis of multinuclear NMR data and SCXRD. As metal-free catalysts for the transfer hydrogenation of ketones to alcohols in isopropanol as solvent and hydrogen source, salts 5–8 showed moderate activities for the transformation of acetophenone to 1-phenyl alcohol. Graphical abstract Image 1 Highlights • Cu catalyzed [3 + 2] cycloaddition 'click' reaction yielded eight new 1,2,3-triazole compounds. • Azolium ring C-4 wingtip para substituted phenoxymethyl group is a common feature of all compounds. • All the salts are moderately active as organocatalysts for the transfer hydrogenation of acetophenone. • Full structural analysis by a variety of techniques that include 2D-NMR and single crystal XRD is presented. [ABSTRACT FROM AUTHOR]

9,9‐Diethylfluorenes bearing chloromethyl, bromomethyl, and iodomethyl groups in the 2, 4, and 7 positions of the aromatic skeleton were prepared and their solid‐state structures determined by single‐crystal X‐ray diffraction analysis. The prepared fluorenes represent not only valuable starting materials for a wide range of fluorene‐based compounds but are also interesting objects for the analysis of the supramolecular motifs in the crystalline state. The X‐ray diffraction experiments revealed that the asymmetric unit of each structure contains one molecule, featuring similar conformations, but differ in their modes of non‐covalent intermolecular bonding. The crystal structures of the chloromethyl and bromomethyl substituted compounds 1 and 2 are primarily stabilized by Hal···Hal and C–H···Hal contacts, whereas the packing of the iodine substituted analogous compound 3 is influenced by triangular I3 synthons, C–H···π interactions and to a less degree by C–H···I contacts. The manuscript provides information about new synthetic routes, new molecules as well as about halogen/hydrogen bonding patterns and other noncovalent interactions in the crystalline state. Concerning the syntheses, the efficient one‐step synthesis of 9,9‐diethylfluorene‐2,4,7‐tricarbaldehyde (8) is also worthy of particular mention. The syntheses of 9,9‐diethylfluorenes bearing halogenomethyl groups in the 2, 4 and 7 positions of the aromatic skeleton, as well as their analyses by X‐ray diffraction are presented. In addition, the efficient one‐step synthesis of 9,9‐diethylfluorene‐2,4,7‐tricarbaldehyde, providing threefold higher yield of the carbaldehyde than the known three‐step reaction sequence, is also described. The crystal packings of the chloromethyl and bromomethyl substituted fluorenes are primarily stabilized by Hal···Hal and C–H···Hal contacts, whereas the packing of the iodine substituted analogue is influenced by a triangular I3 synthon, C–H···π and C–H···I interactions. [ABSTRACT FROM AUTHOR]

8- (4-bromophenoxy) caffeine was synthesized, and its absolute crystal structure was determined by single crystal techniques. The title compound crystallizes in the orthorhombic space group P212121 with a= 7.9056(3), b= 9.1413(3), c= 20.2023(6) Å, and Z=4. The caffeine group makes a dihedral angle of 58.18(9) ° with the bromofenoxy moiety The structure consists of discrete molecule with weak intramolecular hydrogen bond between hydrogen of the methyl group of imidazole ring and oxygen atom of the carbonyl group. The packing of the molecules is oriented in an anti-parallel fashion. [ABSTRACT FROM AUTHOR]

• Synthesis of thiazole appended phenyl acrylamide 1,3-thiazole derivatives (7a-j). • All the synthesized compounds were recognized by IR, NMR, and mass spectral data. • Evaluated the synthesized series for anti-inflamatory and anti-ulcer activity. • Synthesized compounds possess good anti-inflammatory and anti-ulcer activity which was evaluated in-vitro , and in-silico studies. • Compound (7e) with electron releasing methyl group has strongest contact with the active site of H +/ K + ATPase. A great extent of nitrogen containing heterocyclic moiety comprising sulfur atom is recognized as a valuable combination of therapeutics in medicinal chemistry. In particular, thiazoles analogs play a very significant pharmacological role in many potent biological activities, hence drugs like tiazofurin, abafungin, meloxicam, fanetinole, sulphathiazole and thiamine are well known in market. The incorporation of the thiaazole ring can offer enhanced physical-chemical properties to show a wide scope of targets and diverse biological applications. In this view, the title compounds 7(a-j) were synthesized in good yield. The purified compounds were explained by spectroscopic procedures (FT-IR, 1H NMR, 13CNMR, and LC-MS), and lastly, Among the series of (7a-j), compound (7e) showed maximum selectivity for COX-2 with an IC 50 of 8.68±0.31 μM, and the rest of the compounds lies at just below the (7e) which reveals that this compound is quite effective for COX-1 rather than COX-2. The activity found in compound (7e) is attributable to the presence of electron releasing methyl group that has the strongest contact with the active site of H +/ K + ATPase in this study. [ABSTRACT FROM AUTHOR]

In this study, 2‐mercapto‐3‐phenyl‐2,3‐dihydro‐1H‐quinazolin‐4‐one (1), which exists as a thiol and thione tautomer, was treated with acetylacetone to give the target compound, namely, 1‐methyl‐5‐phenyl‐5H‐pyrido[1,2‐a]quinazoline‐3,6‐dione (2). The spectroscopic data, including UV/Vis, IR, 1H NMR, 13C NMR, and mass data, of this compound were recorded. The molecular structures of the starting material (1) and the product (2) were optimized by using density functional theory (DFT) by employing the B3LYP exchange correlation with the 6‐311G (d, p) and 6‐31G++ (d, p) basis sets. The electronic spectra were determined based on time‐dependent DFT calculations in three different solvents (i.e. chloroform, ethanol, and acetonitrile) starting from the same solvated run of the optimized geometry with the same two basis sets. The solvent effects were considered based on the polarizable continuum model (PCM), and the energetic behavior of the compounds and the total static dipole moment (μ) in different solvents were examined in the two basis sets; the results showed that the total energy of the compounds decreased upon increasing the polarity of the solvent. Time‐dependent DFT calculations were performed to analyze the electronic transitions for various excited states that reproduced the experimental band observed in the UV/Vis spectrum. A study on the electronic properties, such as the HOMO and LUMO energies, was performed by the time‐independent DFT approach. Using the gauge‐independent atomic orbital method (GIAO), the 1H NMR chemical shifts were calculated and correlated with the experimental ones. The computed results showed that the introduction of different dielectric media had a slight effect on the stability and reactivity of the title compound as well as on the Milliken atomic charges and the molecular geometry. Besides, the molecular electrostatic potential of target product 2 was evaluated in different solvents. To and fro: 2‐Mercapto‐3‐phenyl‐2,3‐dihydro‐1H‐quinazolin‐4‐one, which exists as a thiol and thione tautomer, was treated with acetylacetone to give 1‐methyl‐5‐phenyl‐5H‐pyrido[1,2‐a]quinazoline‐3,6‐dione. Each compound was spectroscopically characterized, both experimentally and theoretically by time‐dependent DFT, in the gas phase and in chloroform, ethanol, and acetonitrile. [ABSTRACT FROM AUTHOR]

Abstract By using PhSO 2 CF 2 H as the difluoromethylidene equivalent, a novel method for connecting aromatic aldehydes and arylboronic acids via consecutive reactions was developed to obtain structurally diverse 2,2-diaryl-1,1-difluoroethenes. The key step is the palladium-catalyzed dehydrosulfonylative cross-coupling of tosylates that are prepared from PhSO 2 CF 2 H, aromatic aldehydes and tosyl chloride. Mechanistic investigations showed that the reaction proceeds mainly through base-mediated dehydrosulfonylation followed by palladium-catalyzed C(sp2)-C(sp2) cross-coupling reaction. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

A novel bicyclic thiohydantoin fused to pyrrolidine compound, methyl 2-(4-chlorophenyl)-7a-((4-chlorophenyl)carbamothioyl)-1-oxo-5,5-diphenyl-3-thioxo-hexahydro-1H-pyrrolo[1,2-e]imidazole-6-carboxylate, was synthesized by the cyclization reaction of dimethyl 5,5-diphenylpyrrolidine-2,4-dicarboxylate and 4-chlorophenyl isothiocyanate in the presence of 4-(dimethylamino)pyridine to form methyl 2-(4-chlorophenyl)-1-oxo-5,5-diphenyl-3-thioxo-hexahydro-1H-pyrrolo[1,2-e]imidazole-6-carboxylate with concomitant addition reaction of the 4-chlorophenyl isothiocyanate in 79% yield. The structural characterization was performed by NMR, FT-IR, MS and HRMS techniques, and the stereochemistry of the compound was determined by single crystal X-ray diffraction study. In addition, the molecular structure and 1 H and 13 C NMR chemical shifts of the compound were obtained with the density functional theory and Hartree-Fock calculations. Acid dissociation constants of the compound were determined using potentiometric titration method in 25% (v/v) dimethyl sulfoxide-water hydroorganic solvent at 25 ± 0.1 °C, at an ionic background of 0.1 mol/L of NaCl using the HYPERQUAD computer program. Four acid dissociation constants were obtained for the compound, and we suggest that these acid dissociation constants are related to the NH, for two groups of enthiols and enol groups. Antimicrobial activity study was performed against S. aureus , B. subtilis , A. hydrophila, E. coli and A. baumannii as bacterial standard strains, and against M. tuberculosis H37Rv as mycobacterial strain. The compound exhibited antibacterial activity in the range of 31.25–62.5 μg/mL, and antimycobacterial activity with a MIC value of 40 μg/mL against the indicated strains. [ABSTRACT FROM AUTHOR]

Block copolymers of polyisoprene and polystyrene are key materials for polymer nanostructures as well as for several commercially established thermoplastic elastomers. In a combined experimental and kinetic Monte Carlo simulation study, the direct (i.e., statistical) living anionic copolymerization of a mixture of isoprene (I) and 4-methylstyrene (4MS) in nonpolar media was investigated on a fundamental level. In situ ¹H NMR spectroscopy enabled to directly monitor gradient formation during the copolymerization and to determine the nature of the gradient. In addition, a precise comparison with the established copolymerization of isoprene and styrene (I/S) was possible. Statistical copolymerization in both systems leads to tapered block copolymers due to an extremely slow crossover from isoprene to the styrenic monomer. For the system I/4MS the determination of the reactivity ratios shows highly disparate values with rI = 25.4 and r4MS = 0.007, resulting in a steep gradient of the comonomer composition. The rate constants determined from online NMR studies were used for a kinetic Monte Carlo simulation, revealing structural details, such as the distribution of the homopolymer sequences for both blocks, which are a consequence of the peculiar kinetics of the diene/styrene systems. DFT calculations were used to compare the established copolymerization of isoprene and styrene with the isoprene/4-methylstyrene system. A variety of gradient copolymers differing in molecular weight and monomer feed composition were synthesized, confirming strong microphase segregation as a consequence of the blocklike structure. The one-pot synthesis of such tapered block copolymers, avoiding high vacuum or break-seal techniques, is a key advantage for the preparation of ultrahigh molecular weight block copolymers (Mn > 1.2 x 106 g/mol) in one synthetic step. These materials show microphase-segregated bulk structures like diblock copolymers prepared by sequential block copolymer synthesis. Because of the living nature of the tapered block copolymer structures, a vast variety of complex structures are accessible by the addition of further monomers or monomer mixtures in subsequent steps. [ABSTRACT FROM AUTHOR]

Two in,in-cyclophanes that contain methyl groups in their central cavities have been synthesized, and their X-ray structures have been determined. One of these molecules contains a very short nonbonded contact between a hydrogen atom and a methyl group, and the other is the first example of a macrobicyclic compound that contains two inwardly directed methyl groups. [ABSTRACT FROM AUTHOR]

In this work, two series containing a 1,2,4-oxadiazole ring as a central core were synthesized and characterized by common spectroscopic techniques, including FT-IR, 1H-NMR, and elemental analysis. The first series was 3-(4-alkoxyphenyl)-5-(p-methylphenyl)-1,2,4-oxadiazole (Cn), which consisted of alkoxy group in the terminal arm and a methyl group in the other, while, the oxidation reaction of methyl group in a series (Cn) to the carboxy group was the method used to synthesize the second series in this work, 4-(3-(4-alkoxyphenyl)-1,2,4-oxadiazol-5-yl)benzoic acid (Dn). The mesophase behaviors of these two series were studied by optical polarized microscopy (OPM) and differential scanning calorimetry (DSC). The liquid crystalline investigations of the compounds (Cn and Dn) show that the last six homologeus of the series (Cn), (C6-C11), have a monotropic nematic phase, while only the intermediate compounds in the series (Dn), (D3-D9), displayed monotropic nematic phase, also, the liquid crystalline properties in the first and last two compounds in this series (D1, D2, D10, and D11) had disappeared. The differences in liquid crystalline properties between the two series, (Cn and Dn), were discussed through the influences of the different terminal groups (-CH3 and -COOH) in addition to the effect of the 1,2,4-oxadiazole ring and the length of the terminal alkyl chain. [ABSTRACT FROM AUTHOR]

A series of amino acid-derived monohydroxamate compounds A1 – A7 was synthesized and characterized for their coordination properties of Fe(III). The series varies in their skeletal lengths and compositions; some compounds lack external substituents, others are substituted with external functional amino or carboxylic groups, or alternatively inert methyl. Undertaken investigations allowed the determination of stoichiometry, stability constants and spectroscopic parameters of formed ferric complexes. Incorporation of an external functional group with a dissociable proton affects the coordination behavior; the presence of carboxylic or amino groups hampers the formation of mono-, di- and trihydroxamate ferric complexes of presented compounds. The differences in Fe(III) affinity of the monohydroxamates vs trihydroxamates was reflected by the stability constants and pFe, indicating the superior stability of hexadentate complexes. [ABSTRACT FROM AUTHOR]

Halomethyl derivatives of (diethoxyphosphorylmethyl)furan-2(3)-carboxylates containing blocking methyl group in the position 5 of the furan ring were synthesized. In the course of constructing of carbon skeleton of these compounds it was found that alkyl 3-methoxymethyl-, 3-chloromethyl-, and 3-(diethoxyphosphorylmethyl)-5-methyl-2-furoates are halomethylated at elevated temperature in the position 4 of the furan ring. No ring destructure or transformation of the side chain of substituents was observed. The obtained halomethylfurans and their tert-butyl analogs by treating with sodium azide in acetonitrile were converted to corresponding azides. The reduction of latter with triphenylphosphine in ethanol led to formerly unavailable aminophosphonocarboxylates of the furan series. [ABSTRACT FROM AUTHOR]

1-Methyl-2-(2-(prop-2-yn-1-yloxy)benzylidene)hydrazine analogues were readily prepared in good yields by the reaction of 2-(prop-2-yn-1-yloxy)benzaldehydes and methyl hydrazine. The reaction tolerates a variety of substituents on the 2-hydroxybenzaldehyde to form nitro-, halo-, methoxy-, and naphthyl-substituted 1-methyl-2-(2-(prop-2-yn-1-yloxy)benzylidene)hydrazines. The in vitro antioxidant capacity measurements revealed that among all the analyzed hydrazine analogues that surpassed the Trolox standard, 1-(2-(but-3-ynyl)-5-nitrobenzylidene)-2-methylhydrazine had the maximum value, which was approximately 1.7 times that of Trolox. [ABSTRACT FROM AUTHOR]

Postsynthesis modification of solid polymethylaluminoxane (sMAO) with tris(pentafluorophenyl)borane or pentafluorophenol produces highly active metallocene supports "sMMAOs" for use in slurry-phase ethylene polymerization. Characterization of the sMMAOs using elemental analysis, BET isotherm, SEM-EDX, diffuse FT-IR, and solid-state NMR spectroscopy reveals that the surface methyl groups are exchanged for C6F5 and C6F5O moieties respectively, giving a material with reduced aluminum content and a lower specific surface area than sMAO. rac-Ethylenebis(1-indenyl) zirconium dichloride, {(EBI)ZrCl2} immobilized on B(C6F5)3- and C6F5OH-modified sMAO displayed activity increases of 66% and 71% respectively for ethylene polymerization compared to the same zirconocene catalyst precursor on unmodified sMAO. In the case of B(C6F5)3-modified sMAO, this enhanced polymerization activity is accompanied by excellent control of polymer particle size and morphology, and a small decrease in polymer molecular weight and polydispersities. [ABSTRACT FROM AUTHOR]

5-Hydroxy-3,6-dimethyluracil, 5-methoxy-1,3,6-trimethyluracil, earlier unknown 5-methoxy-6- methyluracil, 5-methoxy-1,6-dimethyluracil, and 5-methoxy-3,6-dimethyluracil have been synthesized via alkylation of 5-hydroxy-6-methyluracil with dimethylsulfate in aqueous-alkaline media. The obtained compounds have been identified using ¹H, 13C, and 15N NMR spectroscopy. [ABSTRACT FROM AUTHOR]

The Sonogashira coupling of 1,8-bis(dimethylamino)-2-iodonaphthalene with 2-nitro-, 4-nitro-, 4-(trifluoromethyl)-, and 4-methoxyphenylacetylenes was used to obtain new 2-(arylethynyl)-1,8-bis(dimethylamino)naphthalenes. Three of the four alkynes, except for the o-nitrophenyl derivative, were isomerized in the presence of palladium and porcelain catalysis to the corresponding 2-aryl-9-(dimethylamino)-1,3-dimethyl-1H-benzo[g]indoles. [ABSTRACT FROM AUTHOR]

The reaction of trimethylantimony with methacrylic acid in the presence of tert-butyl hydroperoxide gave trimethylantimony dimethacrylate MeSb(OCCMe=CH) whose structure was confirmed by elemental analysis and IR, H and C NMR, and mass spectra. According to the X-ray diffraction data, the title compound is a trigonal-bipyramidal antimony complex with three methyl group in the pyramid base and two methacrylate ligands in the apices. [ABSTRACT FROM AUTHOR]

Pyrano-flavylium compounds are flavylium derivatives with occurrence in processed foodstuffs such as wine and red fruit juices. In this work, the chemical equilibria of “bio-inspired” pyrano-3-deoxyanthocyanin dyes ( 4–8 ), presenting different substituent groups in D ring (10-methyl, 10-catechol, 10-dimethylaminophenyl, 10-carboxy) as well as in B ring (3′,4′-dihydroxy, 4′-carboxy), were studied for the first time in aqueous solutions by UV–Vis spectroscopy. The presence of a methyl group at C-10 (pigment 4 ) seems to stabilize the flavylium cation (AH + ) shifting the deprotonation of 7-OH to a higher p K a1 (p K a1 = 5.0 ± 0.1). On the other hand, the quinoidal bases (A, A − ) were more stabilized for the pigments which undergo the first acid-base equilibrium at C-10 substituent, as could be observed by the p K a2 constants (p K a2 = 8.4 ± 0.1 and p K a2 = 8.1 ± 0.1, pigments 6 and 8 , respectively). [ABSTRACT FROM AUTHOR]

Reactions of methyl 3,4,6-trioxoalkanoates (3,4-dihydroxy-6-oxo-2,4-alkadienoates) with a mixture of arylamines and aromatic aldehydes or with the corresponding arylidenearylamines lead to the formation of methyl (4- alkanoyl-3-hydroxy-1,5-diaryl-1 H-pyrrol-2-yl)acetates. Structure of the synthesized compounds is discussed basing on IR, H NMR spectroscopy, mass spectrometry, and X-ray diffraction data. [ABSTRACT FROM AUTHOR]

The diazaborole Me3Sn-B{N(Dipp)CH}2 (1; B{N(Dipp)CH}2 = N,N′-bis(2,6-diisopropylphenyl)-2,3-dihydro-1H-1,3,2-diazaborolyl) was prepared by the reaction of Me3SnCl with one equivalent of Li[B{N(Dipp) CH}2]. Single crystals of 1 were obtained from hexane (triclinic space group P1). The diazaborole 1 was monodeprotonated at the heterocycle upon treatment with Li[Me] to give product 2. In contrast to Li[B{N(Dipp)CH}2] which reacted with P4 to give the tetraphosphenediide Li2[{HC(Dipp)N}2B-P(1)P(2)P(3)P(4)-B{N(Dipp)CH}2] (3; δP = 364.5, -29.4; ¹JP(2),P(3) = -509.8 Hz, ¹JP(1),P(2) = -434.3 Hz, ²JP(1),P(3) = -3.7 Hz, ³JP(1),P(4) = 178.9 Hz) and the triphosphenide Li[{HC(Dipp)N}2B-PPP-B{N(Dipp)CH}2] (δP = 665.1, 175.4; ¹JP,P = 500 Hz), the stannyl derivative 1 did not activate white phosphorus. The reaction of 1 with GaCl3 yielded either Me2ClSn-B{N(Dipp)CH}2 (4) or MeCl2Sn-B{N(Dipp) CH}2 (5) depending on the molar ratio of the reactants. The monochlorinated diazaborole Me2ClSn-B{N(Dipp)CH}2 was also obtained by the reaction of 1 with AsCl3. [ABSTRACT FROM AUTHOR]

This paper reports a high-yielding, efficient and facile method in preparing monomers, namely 1,7-bis(hydroxyl(dimethyl)silylmethyl)- m -carborane ( M1 ), 1,7-bis(diethylamino(dimethyl)silylmethyl)- m- carborane ( M2 ), 1,3-dimethyl-1,3-diphenyl-siloxanediol ( M3 ) and diethylaminomethylphenylsilane ( M4 ). The reaction of M2 and M3 to get polymer P1, and the reaction of M1 and M4 to get polymer P2 which has a promising lead in searching for materials with high-temperature properties. The structure of monomers and linear polymers were characterized by NMR and FTIR. Thermal properties of the polyorganocarboranesiloxane elastomers were characterized by DSC and TGA. The results showed that elastomers E1 and E2 have better thermal stability and thermal oxidative stability with 5% weight loss temperatures above 570 °C, 650 °C in nitrogen and 536 °C, 730 °C in air, respectively than that of linear polymers P1 and P2 . The highlight was to study the thermal degradation mechanism of polyorganocarboranesiloxane elastomers using XPS and Solid-state 29 Si NMR. Carborane and organosiloxane outside of samples were gradually oxidized to B 2 O 3 and SiO 2 respectively, the inside only occurred the cleavage of the Si-Ph bond caused by terminal hydroxyl groups which resulted in chain branching and illustrated there was no access for oxygen easy to internal oxidation. [ABSTRACT FROM AUTHOR]

A new, convergent synthesis of (±)-methyl jasmonate is presented. The strategy is based on a C4+C6 synthon approach. The C4 fragment N,4,4-trimethoxy-N-methyl-butanamide ( 5) was prepared in 4 steps starting from chloroacetyl chloride via the previously unreported N,4,4-trimethoxy-N-methylbut-2-enamide ( 4). The coupling of 5 with the C6 synthon, cis-3-hexenyl magnesium chloride ( 6), provided easy access to ( Z)-4-oxodec-7-enal ( 8). The latter was converted to the key intermediate ( Z)-2-(pent-2-en-1-yl)cyclopent-2-en-1-one ( 9) from which (±)-methyl jasmonate can be obtained in high yield using well-established procedures. [ABSTRACT FROM AUTHOR]

The new triplesalophen ligand H6kruseBr was synthesized as a variation of the triplesalophen ligands H6baronR by replacing a phenyl by a methyl group at the terminal ketimine in order to allow closer contacts of trinuclear complexes due to less steric hindrance by the smaller methyl group. The ligand H6kruseBr was used to synthesize the trinuclear complex [(kruseBr)NiII 3], which is insoluble in organic solvents despite the coordinating solvent pyridine. Recrystallization from pyridine results in the complex [(kruseBr){Ni2(Ni(py)2)}], which was characterized by single-crystal X-ray diffraction. Two NiII ions are four-coordinate by the salophen-like subunits while the third NiII ion is six-coordinate by two additional pyridine donors. The analysis of the molecular and crystal structure in comparison to that of Ni3II complexes of (baronR)6- reveals that the methyl group in [(kruseBr){Ni2(Ni(py)2)}] results in less ligand folding and in closer contact distance of two Ni3II complexes by π-π interactions of 3.2 Å. This indicates that trinuclear complexes of H6kruseBr are more suitable than complexes of H6baronR as molecular building blocks for the anticipated synthesis of nonanuclear single-molecule magnets. [ABSTRACT FROM AUTHOR]

A bstract A highly convergent total synthesis of (+)-methynolide, based on two types of stereoselective aldol reaction, was achieved. The C1-C8 and C9-C11 fragments of (+)-methynolide were prepared by a vinylogous Mukaiyama aldol reaction using a vinyl ketene silyl N,O -acetal, and a Ti-mediated aldol reaction of a lactyl-bearing chiral oxazolidin-2-one, respectively. Yamaguchi esterification of both fragments and ring-closing metathesis afforded (+)-methynolide. [ABSTRACT FROM AUTHOR]

The structural phase transition compound {[( CH3) 2CHCH2] 2NH2}•[ CF3COO] ( 1) has been synthesized based on the diisobutylamine and trifluoroacetic acid. The DSC data reveal that 1 undergoes a phase transition at 277 K ( Tc). When one chlorine atom replaces one fluorine atom on trifluoroacetate anion, three order-disorder phase transitions at 251 K ( T1), 282 K ( T2) and 290 K could be achieved owing to a stepwise release of rotation motions of the anion and cation in {[( CH3) 2CHCH2] 2NH2}•[ CF2ClCOO] ( 2). Based on the variable temperature crystal structures, the phase transition in compound 1 is triggered by the rotation of three fluorine atoms on the trifluoroacetate anion synchronized with the motions of the methyl groups on the diisobutylammonium cation. However, in compound 2, the phase transitions can be realized by a sequence of motions of both the anion and cation. Besides, the dielectric- temperature dependences were investigated in order to prove this regulation process. All of this investigation will be beneficial to design and synthesis of the novel phase transition materials and molecular dielectric materials on purpose. [ABSTRACT FROM AUTHOR]

A novel compound, ethyl 7-methyl-1-(4-nitrophenyl)-5-phenyl-3-(thiophen-2-yl)-1,5-dihydro[1,2,4]triazolo[4,3-a]pyrimidine-6-carboxylate (7) was synthesized by reaction of N-(4-nitrophenyl)thiophene-2-carbohydrazonoyl chloride (1) with ethyl 6-methyl-4-phenyl-2-thioxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate (2). The mechanism of the studied reaction is discussed and the assigned structure was confirmed by elemental analysis and spectral data. Moreover, the in vitro antitumor activities against human lung (A-549) and human hepatocellular carcinoma (HepG-2) cell lines were determined by the MTT method, and the results indicated a high potency compared with the employed standard antitumor drug (Cisplatin). [ABSTRACT FROM AUTHOR]

Oxidative C sp3 -H functionalization of 2-methylazaarenes using I 2 -DMSO in open flask has been described first time for the synthesis of 2-azaarenyl benzimidazoles and 2-azaarenyl benzothiazoles. Generally, methyl group of 2-methylazaarenes serves as a carbon nucleophile and in this work the methyl group served as electrophilic carbon (umpolung!) and condensed with o-Phenylenediamine and 2-aminothiophenol to furnish the corresponding benzimidazoles and benzothiazoles in high yields with good substrate scope and functional group tolerance. [ABSTRACT FROM AUTHOR]

A variety of 2-azabicyclo[2.1.0]pentanes were synthesized by the intramolecular nucleophilic substitution of cyclopropylmagnesium carbenoids with magnesium anilide. The 1-chlorocyclopropyl p -tolyl sulfoxides possessing an N -aryl-substituted aminomethyl group were prepared from dichloromethyl p -tolyl sulfoxide, α,β-unsaturated carboxylic acid esters, and anilines in four steps. The deprotonation of the amine with t -BuMgCl followed by sulfoxide/magnesium exchange of the sulfoxides with i -PrMgCl led to the generation of the cyclopropylmagnesium carbenoids possessing a magnesium anilide moiety. Subsequent intramolecular nucleophilic substitution of the cyclopropylmagnesium carbenoids occurred in a 4-exo-tet manner to give the 2-azabicyclo[2.1.0]pentanes. The optically active 2-azabicyclo[2.1.0]pentane was synthesized using a p -tolylsulfinyl group as a chiral auxiliary. [ABSTRACT FROM AUTHOR]

4-Methyl- N-{2-([1-alkyl-2-[2-( p-tolylsulfonylamino)phenyl]benzimidazol-5-yl]iminomethyl)phenyl}-benzenesulfamides (HL) and zinc complexes on their basis ZnL have been synthesized. The structure of the ligands and complexes has been studied by IR, UV, Н NMR spectroscopy, X-ray absorption spectroscopy, and X-ray diffraction analysis. [ABSTRACT FROM AUTHOR]

A series of ethyl 2,7-dimethyl-4-oxo-5-phenyl-3-[(3-phenylisoxazol-5-yl)methyl]-3,5-dihydro-4 H-pyrano[2,3- d]pyrimidine-6-carboxylates was synthesized and screened for antibacterial activity against Gram positive and Gram negative bacterial species. All new compounds were characterized by H, C NMR, IR, and mass spectra. The results of the antibacterial study indicated that all compounds exhibited good to excellent antibacterial activity. [ABSTRACT FROM AUTHOR]

A cascade β-C–H bond trifluoromethylation/C(sp3)–F bond activation/hydrolysis reaction of enamides with Togni’s reagent has been disclosed. This formal C–H bond carbonylation reaction utilizes the CF3 group as a CO surrogate to provide an efficient approach to 1,3-oxazin-6-ones in satisfactory yields. Furthermore, CF3-containing 1,3-oxazin-6-ones could also be accessed using this method by using alkenyl N-ethylamides involving the functionalization of one Csp2–H, one Csp3–H, one Csp2–H, and three Csp3–F bonds. The broad substrate scope of this method enables access to synthetically or pharmaceutically important compounds, which are difficult to access by known methods. [ABSTRACT FROM AUTHOR]

Base-catalyzed domino reaction between N -methylisatin and methyl propiolate afforded four diastereomeric dispiro-1,3-dioxolane bisoxindoles. The reaction mechanism involved sequential 1,2-addition of acetylide anion to the carbonyl group of isatin, 1,2-addition of the resulting oxyanion to a second molecule of isatin, and the final 5- exo - dig cyclization process. [ABSTRACT FROM AUTHOR]

A novel one-pot, “green” protocol to rapidly access pharmaceutically relevant heteroaryl methyl substrates is described. This process allows for a tandem S N 2/Suzuki-Miyaura reaction or Sonogashira reaction across a breadth of chemical diversity with yields ranging between 31 and 87% for the tandem Suzuki-Miyaura process and 50–66% for the tandem Sonogashira process. This procedure tolerates S, N, and O heteroatom linkers and is amenable for both rapid and robust lead development screening. In addition, T-type and N-type calcium channel blocker ( 15 ) was synthesized in 43% yield using this methodology which stands as an improvement in both yield and reaction time of the previously reported synthesis. The one-pot protocol also allows for the inclusion of greater chemical diversity within the scaffold of 15 . [ABSTRACT FROM AUTHOR]

Preparation of a novel hybrid boron-selective adsorbent with N- methyl- d -glucamine functional groups was reported. The adsorbent was synthesized by inverse suspension polymerization method based on chemistry of sol-gel reaction. The structure and morphology of the hybrid adsorbent were characterized by MS, FTIR, XPS, BET analysis and PXRD, etc. The perfectly spherical hybrid adsorbent exhibits exceptionally efficient adsorption of boric acid from the aqueous solution. The boron adsorption behavior on the adsorbent was investigated by varying the dosages of the adsorbent, pH, and competitive ions. The adsorption isotherm was in better accordance with the Langmuir model, exhibiting a theoretical maximum adsorption capacity of 2.02 mmol/g. The adsorption capacity peaks at pH ∼ 9 due to the vast formation of stable tetrahedral structure between dominant B(OH) 4 − and the adsorbent. The presence of Na + ions has slight effect on boron adsorption while Mg 2+ cations significantly enhanced the adsorption capacity because of the simultaneous adsorption attributed by Mg(OH) 2 . [ABSTRACT FROM AUTHOR]

The new bipyridyl-corrole dye 10-(4-methyl-bipyridyl)-5,15-(pentafluorophenyl)corrole, encompassing a coordenative methyl-bipyridine moiety (corrole 2 ), was prepared starting from 5-(pentafluorophenyl)dipyrromethane and reacting it with methyl-bipyridyl-carboxaldehyde by Grykós methodology. It was further characterized by spectroscopic and electrochemical methods. In addition, we investigated experimental photophysical properties, photostability, reactive oxygen species generation (ROS) and aggregation phenomena, which are relevant when selecting photosensitizers used in photodynamic therapy and many other applications. Photophysical properties have demonstrated that the corrole 2 dissolved in dichloromethane has a triplet quantum yield formation of about 51%. Fluorescence and internal conversion quantum yields of 4% and 45%, respectively, have also been determined in order to evaluate which could be was the main pathway of the excited state relaxation. Triplet state formation was also confirmed by measuring indirectly 1 O 2 generation. Additionally, quantum chemistry calculations indicated that the most probable intersystem-crossing pathway takes place through S 1 -T 1 , corroborating our rate equation model. [ABSTRACT FROM AUTHOR]

A series of transition metal ( 1 Mn(II), 2 Ni(II), 3 Cu(II), 4 Zn(II) and 5 Cd(II)) methyl carbazate perchlorate energetic complexes were synthesized in aqueous solution. The crystal structures were determined by single-crystal X-ray diffraction. The complex [Cu(MCZ) 2 ](ClO 4 ) 2 belongs to the triclinic P 1 ¯ space group. The Mn(II), Ni(II), Zn(II) and Cd(II) complexes all are monoclinic, P 2 1 / c space group. Their thermal stabilities were investigated using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). All the compounds show good thermal stabilities ( 1 , 2 , 4 and 5 under 200 °C; 3 under 160 °C). Non-isothermal reaction kinetics parameters, the critical temperatures of thermal explosion, Δ S ≠ , Δ H ≠ and Δ G ≠ were calculated. Their impact and friction sensitivities were tested, and their sensitivity levels are acceptable. The coordinated perchlorates reduce the thermal stability, but improve the decomposition rate immensely as well as the sensitivities. [ABSTRACT FROM AUTHOR]

Although batch reactive distillation process outperforms traditional reactor-distillation processes due to simultaneous reaction and separation of products for many reaction systems, synthesis of Methyl lactate (ML) through esterification of lactic acid (LA) with methanol in such process is very challenging due to difficulty of keeping the reactants together when one of the reactants (in this case methanol) has the lowest boiling point than the reaction products. To overcome this challenge, two novel reactive distillation column configurations are proposed in this work and are investigated in detail. These are: (1) integrated conventional batch distillation column (i-CBD) with recycled methanol and (2) integrated semi-batch and conventional batch distillation columns (i-SBD) with methanol recovery and recycle. Performances of each of these configurations are evaluated in terms of profitability for a defined separation task. In i-SBD column, an additional constraint is included to avoid overflow of the reboiler due to continuous feeding of methanol into the reboiler as the reboiler is initially charged to its maximum capacity. This study clearly indicates that both integrated column configurations outperform the traditional column configurations (batch or semi-batch) in terms of batch time, energy consumption, conversion of LA to ML, and the achievable profit. [ABSTRACT FROM AUTHOR]

Polymeric matrices in the form of microspheres were obtained by copolymerization of the tetrafunctional monomers: 2,3-(2-hydroxy-3-methacryloyloxypropoxy)naphthalene (2,3-NAF.DM) or (bis[4(2-hydroxy-3-methacryloyloxypropoxy)phenyl]sulphide (BES.DM) with styrene (St). Next multistage modification which introduced the methylenethiol groups on the surface of copolymers was carried out. New materials were used in sorption processes to remove toxic heavy metal ions particularly Cd(II), Pb(II), Cu(II), Zn(II), and Ni(II) from aqueous solutions. The effects of the contact time on the sorption of the above-mentioned ions are presented. Sorption capacity depending on the type of monomers, modification, surface character, and porous structure of polymer was determined. The synthesized microspheres 2,3-NAF.DM-St-CH2SH and BES.DM-St-CH2SH indicate potential to adsorb heavy metal ions in the state and batch equilibrium systems. [ABSTRACT FROM PUBLISHER]

O -Alkylation of 7,15,23-tri- tert -butyl-25,26,27-trihydroxy-2,3,10,11,18,19-hexahomo-3,11,19-trioxacalix[3]arene ( 1 H 3 ) with 9-chloromethylanthracene 5 was carried out under different reaction conditions. Variation of the number of anthrylmethyl group introduced at the phenolic rim of hexahomotrioxacalix[3]arene 1 H 3 was achieved through selective O -alkylation using stoichiometric amounts of 9-chloromethylanthracene 5 in acetone to afford the mono- O -alkylated product 2 H 2 An, the di- O -alkylated product 3 HAn 2 and the tri-O -alkylated product partial-cone- 4 An 3 , respectively. Interestingly, by using an acetone/benzene (1:1 v/v) mixed solvent system, the cone - 4 An 3 was successfully synthesized. These results suggest that the solvent can also control the conformation of the O -alkylation products. The possible reaction routes of the cone- 4 An 3 and partial-cone - 4 An 3 are also discussed. [ABSTRACT FROM AUTHOR]