Diisobutyl Ester Research Articles

Catalytic degradation of poplar by Na2CO3 and Na2CO3/Fe under various hydrothermal liquefaction processes

Although the preparation of bio-oil with hydrothermal liquefaction shows the potential for sustainable development, both the, yield and quality were low which greatly hindered its application. Hence, a novel approach was proposed herein to improve the yield and quality of bio-oil. The production of bio-oil from poplar sawdust under direct/stepwise hydrothermal liquefaction (HTL) with Na2CO3 or Na2CO3/Fe as catalyst was investigated. The results showed that the carbon content in heavy oil (HO) gradually increased as the liquefaction temperature increased in the stepwise HTL, while the oxygen in light oil (LO) kept decreasing. The highest total bio-oil yield of 57.09% was obtained from the stepwise Na2CO3/Fe-catalyzed HTL with a residence time of 20 min. Via GC-MS analysis, it was found that the Na2CO3 catalyzed stepwise HTL dramatically improved the yield of dibutyl phthalate. However, Na2CO3/Fe catalyzed HTL helped promote the production of phthalic acid, butyl 2-ethylhexyl ester and phthalic acid, diisobutyl ester.

BIODEGRADATION OF HIGH MOLECULAR WEIGHT POLYCYCLICAROMATIC HYDROCARBON CHRYSENE BY SOIL BACTERIALISOLATES

PAHs (polycyclic aromatic hydrocarbons) are common and dangerous organic pollutants made primarily of carbon and hydrogen. Chrysene is also a potential human carcinogen and a high molecular weight PAH. The current research focuses on chrysene biodegradation, and effective chrysene degrading microbial strains were identified from soil samples taken from the hydrocarbon-contaminated surrounding soil of the Mathura petroleum refinery in Uttar Pradesh, India. The isolated isolates were morphologically examined, and basic biochemical tests were performed. 16sRNA analysis was performed for molecular analysis, and it was discovered that 3AS belongs to Enterobacter sp. and 5AS belongs to Ochrobactrum sp. The biodegradation efficiency of strain 3AS was 60%, while strain 5AS could only digest 55% of chrysene in MSM (Minimal Salt Media). The principal metabolite of chrysene biodegradation discovered in the cultures of strain3AS using the GC-MS (Gas chromatography-mass spectrophotometry) technique, as well assignificant metabolites such as phenol, 2, 5-bis (1,1- dimethyl ethyl), 1-naphthoic acid, 8-methoxy,and 3-nitrophthalic acid. In 5AS cultures, phthalic acid and di-isobutyl ester was detected. Thecatechol-1, 2-dioxygenase gene was not found, but the presence of catechol-2, 3-dioxygenasesuggests that chrysene can be degraded via the meta cleavage pathway.

Catalytic Degradation of Poplar by Fe and Fe/Na <sub>2</sub>CO <sub>3</sub> Under Different Hydrothermal Liquefaction Processes

The production of bio-oil from poplar sawdust Under direct/stepwise hydrothermal liquefaction (HTL) with Na2CO3 or Na2CO3/Fe as catalyst was investigated. The results showed that as the increase of liquefaction temperature in the stepwise HTL, the carbon content in heavy oil (HO) gradually increased, while the oxygen in light oil (LO) kept decreasing. The highest total bio-oil yield of 57.09% was obtained from the stepwise Na2CO3/Fe-catalyzed HTL with a residence time of 20 min. Via GC-MS analysis, it was found that the Na2CO3 catalyzed stepwise HTL dramatically improved the yield of dibutyl phthalate. While the Na2CO3/Fe catalyzed HTL helped promote the production of phthalic acid, butyl 2-ethylhexyl ester and phthalic acid, diisobutyl ester.

Chemical Components of Volatile Oil from Leaves and Stems of Celtis sinensis Pers

Volatile oil compositions of leaves and stems in Celtis sinensis Pers. were reported. Both essential oils were extracted by supercritical fluid extraction of CO2 (SFE-CO2). A total of 44 components were identified in the essential oil of leaves that accounted for 91.09 % of the compositions. The most abundant constituents were found in the leaves, mainly including phthalic acid, diisobutyl ester (20.79 %), cyclohexanone (16.47 %), 2,2'-methylenebis[6-(1,1-dimethylethyl)-4-methyl]-phenol (8.86 %) and 2,2,3,4-tetramethyl- hex-5-en- 3-ol (5.13 %). There were 52 components found in the volatile oil of stems, representing 96.71 % of the total area. Stems essential oil constituents with higher content were found such as phthalic acid, diisobutyl ester (23.76 %), cyclohexanone (14.78 %), 2,2'-methylenebis[6-(1,1-dimethylethyl)-4-methyl]- phenol (9.50 %), 1,3-dimethyl- benzene (6.07 %). Twenty-three common compounds accounted for 65.69 % and 71.63 % of total contents in leaves and stems showed a certain similarity in both essential oils. Meanwhile, 50 non-common compositions resulted in some subtle differences to some degree.

Evaluation of the effect of mericitabine at projected therapeutic and supratherapeutic doses on cardiac repolarization in healthy subjects: A thorough QT/QTc study.

Mericitabine, the di-isobutyl ester prodrug of the cytidine nucleoside analog, is a potent and selective hepatitis C virus NS5B polymerase inhibitor. This thorough QT/QTc study evaluated the effect of mericitabine on cardiac repolarization in healthy subjects. This was a randomized, double-blind, placebo- and active-controlled, 4-way crossover study. A total of 60 subjects were enrolled and randomized to receive a single dose of mericitabine 1,500 mg, 9,000 mg, moxifloxacin 400 mg and placebo in randomly assigned treatment sequences, with at least 14 days between doses. The primary endpoint was the mean difference in baseline-adjusted QT interval using a study-specific correction method (QTcS) between mericitabine and placebo. The upper one-sided 95% confidence interval for the placebo-subtracted change from baseline in QTcS was <10 milliseconds and the mean difference from placebo was <5 milliseconds at all time points for both mericitabine doses. The positive control moxifloxacin caused a pronounced increase in QTcS that peaked 4 hours after oral administration. Furthermore, there was no trend of a concentration-dependent effect of mericitabine on QTcS. In conclusion, mericitabine does not have a clinically or statistically significant effect on cardiac repolarization in healthy subjects at single doses up to 9,000 mg.

Thiocyanate linkage isomerism in the isobutyl ester form of the ruthenium dye known as N3

Using a modification of a recently reported convenient synthesis of the isobutyl ester form of the bis(isothiocyanato) ruthenium dye (N3), we report the isolation and spectroscopic characterization of the minor isomer in which one NCS− is N-bound and the other is S-bound. The synthesis involves the reaction of Ru(iBu2dcbpy)2Cl2, where iBu2dcbpy is the diisobutyl ester of 4,4′-dicarboxy-2,2′-bipyridine, with a source of thiocyanate. The impact of the isocyanate salt, solvent, and temperature on the yield of the linkage isomers is presented. In addition to the two linkage isomers 1 and 2, the partially substituted chloroisothiocyanato complex 3, Ru(iBu2dcbpy)2Cl(NCS), was also isolated. Selective removal of the chloride using silver triflate provided a path to [Ru(iBu2dcbpy)2(pyridine)(NCS)]OTf, 4, in high yield. The complexes were characterized by 1H and 13C NMR, IR, and electronic absorption spectroscopies and mass spectrometry. At 80 °C in DMSO-d6, the isomerization of 2 to 1 is complete and exhibits first-order kinetics with a rate constant of 0.00014 s−1. Room temperature hydrolysis of the isobutyl ester groups of 2 using [nBu4 N]OH in acetonitrile produced a mixture of the two linkage isomers.

Biochemical composition and antioxidant capacity of extracts from Podophyllum hexandrum rhizome.

BackgroundPodophyllum hexandrum Royle (P. hexandrum) is a perennial herb and widely used in clinic. The present study was designed to separate and identify the biochemical composition and antioxidant capacity of extracts from P. hexandrum rhizome.MethodsThe ethyl acetate and ethanol extracts from P. hexandrum rhizome were analyzed by GC-MS (gas chromatography–mass spectrometry), and the antioxidant capacity of the extracts and the components was tested by using the DPPH (2, 2-diphenylpicrylhydrazyl) and FRAP (Ferric reducing/antioxidant power) assays.ResultsThe rhizome extracts had greater antioxidant capacity than the petiole extracts in DPPH and FRAP assays. About 16 kinds of main reactive oxygen components were identified in the extracts. Components of PADE (Phthalic acid, diisobutyl ester), BADE (1,2-Benzenedicarboxylic acid, diisooctyl ester), Polyneuridine, PODD (Podophyllotoxin, deoxy), β-Sitosterol and POD (Podophyllotoxin) showed the antioxidant capacity in some degree. PODD, POD, and Polyneuridine showed stronger antioxidant capacity with the IC50 and FRAP values of 9.61 ± 0.81 and 2923.98 ± 21.89 μM, 9.98 ± 0.24 and 2847.27 ± 14.82 μM, and 13.37 ± 0.35 and 2404.32 ± 36.88 μM, respectively, than the positive control ASA (Ascorbic acid) with the values of 60.78 ± 1.22 and 1267.5 ± 30.24 μM (P < 0.01).ConclusionsPODD, POD, and Polyneuridine are very critical for the antioxidant capacity in the extract of P. hexandrum rhizome. These results provide useful biochemical basis and information for the potential use of this plant.

Chemical constituents of marine sponge Callyspongia sp. from the South China Sea

Nine known compounds were isolated from the South China Sea sponge Halichondria sp. and the antibacterial activities of compounds 1 - 6 were tested. Their structures were identified as 1 , 2 , 3 , 4-tetrahydro-3-carboxy-2-carboline ( 1 ) , tryptophan ( 2 ) , cyclo- ( Ile-Pro ) ( 3 ) , seco- ( ( S ) -Pro-Val ) ( 4 ) , cyclo- ( Ala-Pro ) ( 5 ) , cholesterol ( 6 ) , bis ( 2- ethylhexyl ) phthalate ( 7 ) , phthalie acid butyl isobutyl ester ( 8 ) , and 1 , 2-benzenedicarboxylic acid diisobutyl ester ( 9 ) on the basis of detailed spectroscopic analysis and comparison with the data reported in the literature.

Diastereoselective Synthesis of New Dialkylphosphorylhydrazones

A series of 22 dialkylphosphorylydrazones (dialkyl ester, N′-[(1E)-(R1 phenyl)methylene]-phosphorohydrazidic acid), 20 of them new, along with three new N,N′-bis (diisobutylphosphorylthioamide)diamines (bis-[diisobutyl ester), N-thioxomethylene]-, diamine)phosphora-midic acid, were prepared and characterized by IR, 1H NMR, 13C NMR, 31P NMR, and mass spectrometry. The analysis of 1H NMR, 13C NMR, 31P NMR, and NOE spectra confirmed the observation of the single diastereoisomer E in the synthesis of dialkylphosphorylydrazones. The results of a molecular modeling study performed in order to investigate the mechanism of the synthesis of dialkylphosphorylydrazones are in agreement with the experimental results, i.e., the favored formation of diastereoisomer E over Z.

Palladium(II) complexes with R 2edda-derived ligands. Part II. Synthesis, characterization and in vitro antitumoral studies of R 2eddip esters and palladium(II) complexes

New R 2eddip-type esters (R = cyclopentyl, L3·2HCl 1.5H 2O; cyclohexyl, L4·2HCl·H 2O) and corresponding palladium(II) complexes, [PdCl 2 L3] ( 3) and [PdCl 2 L4]·H 2O ( 4), as well as [PdCl 2 L2] ( 2; L2 diisobutyl ester of eddip) were synthesized and characterized by IR, 1H and 13C NMR spectroscopies and elemental analysis. The crystal structure of L3·2HCl·2CHCl 3 was resolved and is given herein. The NMR spectroscopy confirmed the presence of two isomers (from three possible) for each palladium(II) complex. DFT calculations support the formation of two diastereoisomers. In addition, antitumoral investigations were performed and these investigations also included the diisopropyl ester of eddip ( L1) and corresponding palladium(II) complex, [PdCl 2 L1] ( 1). In vitro antiproliferative activity was determined against several tumor cell lines HeLa, Fem-x, K562 and rested and stimulated normal immunocompetent cells (human peripheral blood mononuclear cells -PBMCs) using MTT test.

Comparative analysis of essential oils from eight herbal medicines with pungent flavor and cool nature by GC–MS and chemometric resolution methods

Systematic comparative research was conducted on essential oils from eight traditional Chinese medicines (TCM) of pungent flavor and cool nature because the essential oils are the main active ingredients of herbs of this kind. The work was based on their component analysis by gas chromatography-mass spectrometry (GC-MS), on their retention indices, as well as on chemometric resolution methods. A total of 144 compounds were tentatively identified, accounting for 69.0% to 91.8% of the total essential oils. It is worth noting that there are 67 compounds in at least three of these eight essential oils. Moreover, many biologically active compounds, such as hexanal, alpha-pinene, camphene, beta-pinene, p-cymene, limonene, eucalyptol, (Z)-ocimene, gamma-terpinene, camphor, p-menthone, 4-terpineol, alpha-terpineol, carvone, eugenol, caryophyllene, beta-farnesene, alpha-curcumene, beta-selinene, delta-cadinene, caryophyllene oxide, cedrol, n-hexadecanoic acid, benzaldehyde, benzeneacetaldehyde, phthalic acid diisobutyl ester, linoleic acid, tetradecanoic acid, (Z,Z,Z)-9,12,15-octadecatrienoic acid, eucalyptol, pentadecanoic acid, hexadecanoic acid methyl ester, linoleic acid methyl ester, exist in at least four of the eight essential oils. These results might help us to understand why the eight herbs are all of pungent flavor and cool nature according to the theory of TCM, and may provide a useful chemical basis for future research on herbs of this kind.

Reaction of Stereoisomers of 5‐Isopropyl‐4‐methyl‐1,3‐dioxane with Esters of Monosubstituted Boric Acid.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Reaction of stereoisomers of 5-isopropyl-4-methyl-1,3-dioxane with esters of monosubstituted boric acid

Gas-liquid chromatography was used to establish that the reactivity of the cis isomer in the reaction of 5-isopropyl-4-methyl-1,3-dioxane with the diisobutyl ester of isobutylboric acid leading to the corresponding 1,3,2-dioxaborinane is greater than for the trans isomer. An AM1 calculation for the energy of the intermediate ions in this reaction with model derivatives of boric acids: dioxyborane and the dimethyl ester of methylboric acid showed that one of the probable reasons for the observed behavior is the lower barrier for conversion of the intermediate bipolar structure of the cis derivative in the step involving formation of the endocyclic B-O bond.

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

The properties of an optical sensor based on the oxygen-induced and temperature-induced luminescence quenching of tetrakis(pentafluorophenyl)porphyrinatoplatinum (PtTFPP) and 3,9-perylenedicarboxylic acid diisobutyl ester immobilized in a polystyrene film were investigated. The luminescence from PtTFPP in a polystyrene film was quenched by oxygen. On the other hand, the luminescence from 3,9-perylenedicarboxylic acid diisobutyl ester was not quenched by oxygen. Thus, the coincidence measurement for oxygen and temperature changes were attained using PtTFPP and 3,9-perylenedicarboxylic acid diisobutyl ester immobilized in polystyrene film.

Anaerobic toxicity and biodegradability of hydrolysis products of chemical warfare agents.

The toxicity and biodegradability of the main hydrolysis products of chemical warfare agents were investigated under methanogenic conditions. Among the tested substances, only MPhA does not have any toxic effect with regard to the aceticlastic methanogenic activity. The toxicity of other compounds varied between moderate (TDG, mercaptoethanol) to strong (ethanolamine, diisobutyl ester of MPhA). Biodegradability tests showed that all the products of chemical detoxification of mustard gas (ethanolamine, ethylene glycol, TDG, mercaptoethanol) can be biomineralized under methanogenic conditions. On the contrary, phosphorus-containing compounds from the chemical detoxification of nerve warfare agents (Sarin, Soman, Vx-gases) are quite persistent under these conditions.

Reaction of substituted 1,3-dioxanes with the disobutyl ester of isobutylboric acid

The reaction of subsitituted 1,3-dioxanes with the diisobutyl ester of isobutylboric acid leads to the corresponding 1,3,2-dixaborinanes. The determining factor in the reactivity of the 1,3-dioxanes is the degree of substitution of the acetal atom.

Gas chromatography—mass spectrometry of perindopril and its active free metabolite, an angiotensin convertase inhibitor: choice of derivatives and ionization modes

Perindopril, a perhydroindole compound and a novel class of angiotensin convertase inhibitor, after oral administration leads to an active metabolite by de-esterification of an ethyl ester. Routine biological measurements are currently done using a radioimmunological assay, but a mass fragmentographic method was developed using plasma spiked with the drugs, which were then derivatized to the isobutyl ester heptofluorobutyramide and assayed using ammonia negative chemical ionization. Levels of 100 pg/ml were assayed. However, isobutanol derivatization provoked partial transesterification of the ethyl ester of the parent drug into the diisobutyl ester derivative, which corresponds to the active metabolite. A second method of derivatization to stable trimethylsilyl esters preserved the original ethyl ester of the parent drug. Despite the lower ionization yields, the mass fragmentographic method was sensitive and accurate enough to work satisfactorily at the 2 ng/ml level in spiked plasma, which is the level found currently in patients.