??????????????? ????????? ????????? ?????? ??? ????????????

??????????????? ????????? ???????????? ???????????? ?????? ?????????????????? ??????????????? ?????? ???????????? ??????. ??? ??????????????? ??????????????? ??? ?????? ????????? ???????????? ????????? ??????????????? ????????? ???????????????. ?????? ??????????????? ????????? ??? ?????? ????????? ???????????????, ??? ?????? ????????? diethylnitrosamine (DEN)??? C3H/HeN ?????? ?????? ?????? ???????????? ??? ?????? ????????? ????????? ???????????????. DEN?????? ????????? ???????????? ?????? alkaline phosphatase (ALP) ??????, TUNEL positive ???????????? ??????, ??? ???????????? ?????? ???????????? duct??? ??????, ?????????????????? ????????????, Masson???s trichrome ???????????? ????????? ???????????? ???, ?????? ?????? ?????? ??? ????????? ????????? ???????????? ?????? ???????????? ?????? ?????? ????????? ??? ?????????. ?????????, ??????????????? ?????? ???????????? ????????? ?????? ?????????????????? ??????, ?????? ?????? ??? ????????? ???????????? ??????????????? ???????????? ???????????? ???????????? ?????? ?????? ????????? ??? ?????????. ???????????? ???????????? ????????? ???????????? ??????, ???????????? ???????????? ???????????? ?????? ????????? ???, solvent partition ????????? ???????????? ????????? ???????????? hexane, ethyl acetate, water ???????????? ???????????????. ?????? ??????????????? ?????? ????????? ??????????????? ??????????????? ???, ethyl acetate ???????????? ??????????????? ????????? ?????????????????? ??????????????? ?????? ??????????????? ???????????? ????????? ????????? ????????? ??? ?????????. ????????? ethyl acetate???????????? ???????????? ????????? ????????? ??? ?????????, ??????????????? ????????? ??? ?????? ????????? ????????? ?????????. ???????????????, ??????????????? ????????? ????????????????????? ?????? ????????? ??? ?????? ????????? ???????????? ?????? ??????????????? ????????? ??? ?????? ????????? ????????? ????????? ?????? ???????????????. ?????????, ?????? ??????????????? ?????? ???????????? ?????? ??? ?????? ?????? ???????????? ??????????????? ?????? ????????? ????????? ??? ?????? ????????? ???????????? ??????.clos

Methods for synthesizing diethyl carbonate from ethanol and supercritical carbon dioxide by one-pot or two-step reactions in the presence of potassium carbonate

Carbon dioxide sequestration was studied by synthesizing diethyl carbonate (DEC) from ethanol and CO2 under supercritical conditions in the presence of potassium carbonate as a base. The co-reagent was ethyl iodide or a concentrated strong acid. This sequestration reaction occurs in two steps, which were studied separately and in a one-pot reaction. An organic-inorganic carbonate hybrid, potassium ethyl carbonate (PEC) is generated at the end of the first step. This intermediate was characterized and was found to be a target molecule for CO2 capture. Different co-reactants, such as ethyl iodide and concentrated strong Brönsted acid, were compared in the second step and used to investigate the reactivity of the hybrid. With ethyl iodide as the co-reactant, one-pot DEC synthesis gave higher yields (46%) than two-step production. The supercritical CO2 acts as a swelling solvent and compatibilizing agent in the reaction medium, favoring interactions between ethanol and CO2 and between PEC and ethyl iodide. The use of a phase transfer catalyst (PTC) increased DEC production (yield 51%) without increasing the amount of diethyl ether (DEE) produced as a by-product (yield 2%)

Screening of Indonesia Medicinal Plants Producing Quorum Sensing Inhibitor

Antibiotic resistance of bacteria lead to create different way in the pathogen bacteria handling such us inhibit their quorum sensing mechanism. The goal of this study is to search quorum sensing inhibitor of seven Indonesia medicinal plants. The experiment was conducted by extracting the plants using ethyl acetate subsequently tested on reporter carrying luxR homologous and luxCDABE genes. Reporter luminescence used as indicator of quorum sensing inhibition. The results show that ethyl acetate extracts of buah adas (Foeniculum vulgare), bunga lawang (Illicium verum), selasih (Ocimum basilicum), temu ireng (Curcuma aeruginosa), temu giring (Curcuma heyneana), dan temu lawak (Curcuma xanthorriza) mampu menginhibisi quorum sensing pada Pseudomonas aeruginosa. Further analysis was done by observing several metabolites which directly influenced by quorum sensing. The experiment was design by growth Pseudomonas aeruginosa at LB medium occurring fennel seeds ethyl acetate extract in the various concentration. Number of biofilms, rhamnolipid and activity of LasA produced by Pseudomonas aeruginosa were then measured. The experiment shown LasA activity inhibition reaching 100% was obtained at growth media containing 1.52 mg / ml extract. There was a decrease at inhibition activity when the extract concentration was added above this value. Meanwhile, 19% inhibition of rhamnolipid production occurred at concentrations of ethyl acetate extract of 2.03 mg / ml in growth media. Different results obtained in the production of biofilm which is induced by fennel seeds ethyl acetate extract at the level 123%

Reductive Biotransformation of Ethyl Acetoacetate: A Comparative Studies using Free and Immobilized Whole Yeast Cells

Bioreduction of ethyl acetoacetate with free and immobilized yeast whole cell was achieved by using water and sucrose combination. After detachment from immobilized beads under basic condition, the corresponding ethyl(S)-(+)-3-hydroxybutanoate was isolated with 98 to 100% yield. Immobilized beads of yeast whole cell were prepared at different temperature which affects the morphology and physiology of the beads for the diffusion of the enzyme, which shown the maximum conversion of the substrate to products as compared to the free yeast whole cell

Ethyl and isopropyl 4-ferrocenylbenzoate.

The title compounds, [Fe(C5H5)(C14H13O2)] and [Fe(C5H5)- (C15H15O2)], respectively, contain the ferrocenyl 5(C5H4) and phenylene ±C6H4± rings in a nearly coplanar arrangement, with interplanar angles of 6.88 (12) and 10.5 (2), respectively. Molecules of the ethyl ester form dimers through 5(C5H5)CÐ H O C hydrogen bonds, with graph set R22 (20), and, together with Csp3ÐH (C5H5) interactions, generate a one-dimensional column (irregular ladder). Molecules of the isopropyl ester aggregate through 5(C5H5)CÐH (C6H4) interactions

Organosolv pretreatment of Sitka spruce wood: conversion of hemicelluloses to ethyl glycosides

A range of organosolv pretreatments, using ethanol:water mixtures with dilute sulphuric acid, were applied to Sitka spruce sawdust with the aim of generating useful co-products as well as improving saccharification yield. The most efficient of the pretreatment conditions, resulting in subsequent saccharification yields of up to 86%, converted a large part of the hemicellulose sugars to their ethyl glycosides as identified by GC/MS. These conditions also reduced conversion of pentoses to furfural, the ethyl glycosides being more stable to dehydration than the parent pentoses. Through comparison with the behaviour of model compounds under the same reaction conditions it was shown that the anomeric composition of the products was consistent with a predominant transglycosylation reaction mechanism, rather than hydrolysis followed by glycosylation. The ethyl glycosides have potential as intermediates in the sustainable production of high-value chemicals

Dielectric relaxation of the ionic liquid 1-ethyl-3-methylimidazolium ethyl sulfate: microwave and far-IR properties

Dielectric relaxation of the ionic liquid, 1-ethyl-3-methylimidazolium ethyl sulfate (EMI+ETS–), is studied using molecular dynamics (MD) simulations. The collective dynamics of polarization arising from cations and anions are examined. Characteristics of the rovibrational and translational components of polarization dynamics are analyzed to understand their respective roles in the microwave and terahertz regions of dielectric relaxation. The MD results are compared with the experimental low-frequency spectrum of EMI+ETS–, obtained via ultrafast optical Kerr effect (OKE) measurements

Synthesis and characterization of nickel(II) maltolate complexes containing ancillary bisphosphine ligands

Cationic nickel(II) complexes containing chelating O,O'-donor maltolate or ethyl maltolate ligands in conjunction with bidentate bisphosphine ligands Ph₂P(CH₂)nPPh₂ were prepared by a one-pot reaction starting from nickel(II) acetate, bisphosphine, maltol (or ethyl maltol), and trimethylamine, and isolated as their tetraphenylborate salts. An X-ray structure determination of [Ni(maltolate)(Ph₂PCH₂CH₂PPh₂)]BPh₄ shows that the maltolate ligand binds asymmetrically to the (slightly distorted) square-planar nickel(II) center. The simplicity of the synthetic method was extended to the synthesis of the known platinum(II) maltolate complex [Pt(maltolate)(PPh₃)₂]BPh₄ which was obtained in high purity

Ring transformations in reactions of pyrimidine and N-alkylpyrimidinium salts with nucleophile

Paper IOn treatment with liquid ammonia at -33°C, the quaternary pyrimidinium salts, i.e. 1-methylpyrimidinium methyl sulfate, 1,2-dimethylpyrimidinium iodide, 1,4,6-trimethyl-pyrimidinium iodide and 1,2,4,6-tetramethylpyrimidinium iodide demethylate yielding pyrimidine. 2-methyl-, 4,6-dimethyl- and 2,4.6-trimethylpyrimidine, respectively. It was observed that under these conditions 1-methyl-[1,3- 15N]-pyriniidiniuni methyl sulfate yields [1- 15N]-pyrimidine. By measuring the PMR spectra of above- mentioned pyrimidinium salts in liquid ammonia it is shown that these salts undergo covalent amination on the 1,6-azomethin bond. These results indicate that the demethylation reaction occurs via an Addition-NucleophileRing-Opening-Ring Closure mechanism.Paper IIOn treatment with active methylene compounds in basic media the quaternary pyrimidinium salts, i.e. methyl 1-methylpyrimidinium sulfate, 1-methyl-4-phenylpyrimidinium iodide and 1-methyl-5- phenylpyrimidinium iodide are converted into pyridine derivatives. The mechanism of the reaction is discussed.Paper IIIOn treatment of the quaternary pyrimidinium salts i.e. 1-methyl-4-phenylpyrimidinium iodide and 1-methyl-5-phenylpyrimidinium iodide with cyanamide, O -methylisouronium chloride or bis[S-methylisothiouronium] sulfate in basic media, 2-amino-4-phenylpyrimidine and 2-amino-5-phenylpyrimidine are formed respectively. A ring transformation is involved in which the two-atom fragment N(1)-C(2) of the pyrimidine ring is replaced by an N-C fragment of the reagent. On reacting 1-methylpyrimidinium iodide with benzamidinium chloride or pivalamidinium chloride in a solution of sodium ethoxide in ethanol, 2-phenylpyrimidine and 2- tert -butylpyrimidine are formed respectively.It is proved by 15N-labelling that this nucleophilic substitution occurs via a ring transformation in which the N(1)- C(2)-N(3) fragment of the pyrimidine is replaced by the N-C-N fragment of the amidine. These reactions are new examples of a nucleophilic substitution occurring according to an S N (ANRORC) mechanism.Paper IVReaction of 4-alkoxy- or 4,6-dialkoxypyrimidines with 1 equivalent of triethyloxonium tetrafluoroborate yields 4-alkoxy-N-ethyl or 4,6-dialkoxy-N-ethylpyrimidinium salts, respectively. With two or more equivalents of this reagent, rearrangement of N-ethyl-alkoxypyrimidinium salts into 1-ethyl-3-alkyl-1,4(3,4)-dihydro-4-oxopyrimidinium salts takes place. These rearrangements can also be performed by heating. The mechanism of these rearrangement reactions is discussed.Paper VThe crystal and molecular structures of two isomeric compounds, 1-ethyl-4,6-diethoxypyrimidinium tetrafluoroborate and 1,3-diethyl-1,4(3,4)-dihydro-6-ethoxy-4-oxopyrimidinium tetrafluoroborate, reaction products of 4,6-diethoxypyrimidine with Meerwein reagent [O(C 2 H 5 )3+BF4-] , have been determined by means of X-ray diffraction.1-Ethyl-4,6-diethoxypyrimidinium tetrafluoroborate is monoclinic a=10.794, b=13.361,c=10.892 Å, β =112.6°, space group P2 1 /n, four molecules per unit cell.1,3-Diethyl-1,4(3,4)-dihydro-6-ethoxy-4-oxopyrimidinium tetrafluoroborate is monoclinic, a=17.637, b=14.054, c=11.501 Å, β =101.7°, space group C2/c, eight molecules per unit cell.In both structures the fluoroborate ions are disordered. The bond distances in the π-electron systems are reasonably well described in terms of a small number of resonance structures.Paper VITreatment of 1,3-diethyl-1,4(3,4)-dihydro-4-oxopyrimidinium tetrafluoroborate and its 2-phenyl, 6-phenyl, 6-methyl and 6-ethoxy derivatives with aqueous ammonia resulted in the formation of a mixture of open-chain compounds i.e. N -formyl(acetyl,benzoyl)- N -ethyl-3-(ethylamino)acrylamides and N -ethyl-3-[formyl(acetyl,benzoyl)ethylamino]-acrylamides. They are formed by cleavage of the pyrimidine ring between the N(1)-C(2) and N(3)-C(2) bond, respectively. In liquid ammonia the same ring cleavage generally occurs; however, in the case where a 6-ethoxy group is present, recyclisation can take place, leading to 6-(ethylamino)pyrimidine derivatives. This degenerate ring transformation has been observed also with the 2-methyl and 2-phenyl derivative of 1,3-diethyl-1,4(3,4)-dihydro-6-ethoxy-4-oxopyrimidinium tetrafluoroborate. Evidence is presented by means of 1H-NMR and 13C-NMR spectroscopy that all these reactions are iniated by attack of NH 3 at the C(2)-position. Some of the above-mentioned open-chain compounds underwent a ring closure to the initially used 1,3-diethyl-1,4(3,4)-dihydro-4-oxopyrimidinium tetrafluoroborates on treating them with hydrofluoroboric acid in absolute ethanol.Paper VIIOn treatment with liquid ammonia at -33° the quaternary pyrimidinium salts i.e. 4-ethoxy-1-ethyl- and 4,6-diethoxy-1-ethylpyrimidinium tetrafluoroborate undergo amino-de-ethoxylation, yielding 1,4-dihydro-1-ethyl-4-iminopyrimidine hydrogen tetrafluoroborate and a mixture of 1,4-dihydro-6-ethoxy-1-ethyl-4-imino- and 1,6-dihydro-4-ethoxy-1-ethyl-6-iminopyrimidine hydrogen tetrafluoroberate, respectively. 1H-NMR and 13C-NMR spectroscopic evidence is presented for the fact that compounds 1 and 3 easily give σ-adducts at position 2. Using 15N-labelled ammonia it was shown that in these amino-de-ethoxylation reactions the substitution at C(4) or C(6) does not involve ring opening but probably occurs via an S N (AE n ) process. Reaction of 4-ethoxy-1-ethyl-2-phenyl-, 6-ethoxy-1-ethyl-4-phenyl-, 4,6-dimethoxy-1-ethyl-2-phenyl- and 4,6-dimethoxy-1-ethyl-2-methylpyrimidinium tetrafluoroborate with liquid ammonia gives besides the amino-de-ethoxylation product degenerate ring transformations leading to the N-deethylated products 14-16 and 4(6)-ethylaminopyrimidines 17-19. The salt 11 and 1,6-dihydro-1-ethyl-6-imino-4-phenylpyrimidine hydrogen tetrafluoroborate undergo, with potassium hydroxide, a Dimroth rearrangement to pyrimidines 20 and 17, respectively. Paper VIIIThe mechanism of the conversion of pyrimidine into 5-ethyl-2-methylpyridine has been investigated. It has been proved, using the labelled compounds [1,3- 15N]pyrimidine, [4,6- 14C]pyrimidine and [5- 14C]pyrimidine, that this reaction proceeds via a mechanism, in which the pyrimidine ring is fragmentated into two molecules of HCN and one molecule of N -methylacetaldimine. Four molecules of this imine undergo an aldol type condensation leading to 5-ethyl-2-methylpyridine

Fermentative capability and aroma compound production by yeast strains isolated from Agave tequilana Weber juice

Five yeast strains isolated from agave juice were studied for their fermentative and aromatic capacity. The experiments were performed using agave juice supplemented with ammonium sulphate, as is commonly done in tequila distilleries. Three strains classified as Saccharomyces cerevisiae showed high biomass and ethanol production, as well as higher ethanol tolerance than those classified as Kloeckera africana and Kloeckera apiculata, which showed scarce growth. The results suggest that Kloeckera strains were affected by nutritional limitation and/or toxic compounds present in agave juice. Agave juice analyses showed a lower amino acid content than those reported in grape juice. S. cerevisiae strains produced predominantly amyl and isoamyl alcohols, n-propanol, 2-phenyl ethanol, succinic acid, glycerol, methanol, isoamyl acetate, ethyl hexanoate, acetaldehyde and isobutanol, whereas Kloeckera strains showed a high production of acetic acid, 2-phenyl ethyl acetate and ethyl acetate. The methanol concentration was significantly different among the yeasts studied. The diversity between three S. cerevisiae strains were higher for the aromatic profile than for genetic level and kinetic parameter. On the other hand, the diversity of Kloeckera yeasts were lower than Saccharomyces yeasts even when belonging to two different species