Displaying publications 1 - 20 of 148 in total

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  1. Ethyl 2-(4-benzyl-3-methyl-6-oxo-1,6-dihydropyridazin-1-yl)acetate: crystal structure and Hirshfeld surface analysis
    Zaoui Y, Ramli Y, Taoufik J, Mague JT, Jotani MM, Tiekink ERT, et al.
    Acta Crystallogr E Crystallogr Commun, 2019 Mar 01;75(Pt 3):392-396.
    PMID: 30867956 DOI: 10.1107/S205698901900241X
    The title compound, C16H18N2O3, is constructed about a central oxopyridazinyl ring (r.m.s. deviation = 0.0047 Å), which is connected to an ethyl-acetate group at the N atom closest to the carbonyl group, and benzyl and methyl groups second furthest and furthest from the carbonyl group, respectively. An approximately orthogonal relationship exists between the oxopyridazinyl ring and the best plane through the ethyl-acetate group [dihedral angle = 77.48 (3)°]; the latter lies to one side of the central plane [the Nr-Nr-Cm-Cc (r = ring, m = methyl-ene, c = carbon-yl) torsion angle being 104.34 (9)°]. In the crystal, both H atoms of the N-bound methyl-ene group form methyl-ene-C-H⋯O(ring carbon-yl) or N(pyridazin-yl) inter-actions, resulting in the formation of a supra-molecular tape along the a-axis direction. The tapes are assembled into a three-dimensional architecture by methyl- and phenyl-C-H⋯O(ring carbon-yl) and phenyl-C-H⋯O(ester carbon-yl) inter-actions. The analysis of the calculated Hirshfeld surface indicates the dominance of H⋯H contacts to the overall surface (i.e. 52.2%). Reflecting other identified points of contact between mol-ecules noted above, O⋯H/H⋯O (23.3%), C⋯H/H⋯C (14.7%) and N⋯H/H⋯N (6.6%) contacts also make significant contributions to the surface.
    Matched MeSH terms: Acetates
  2. Fulltext Crystal structure of [(2R,3R,4S)-3,4-bis(acet-yloxy)-5-iodo-3,4-di-hydro-2H-pyran-2-yl]methyl acetate
    Zukerman-Schpector J, Caracelli I, Stefani HA, Shamim A, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2015 Jan 1;71(Pt 1):o53-4.
    PMID: 25705505 DOI: 10.1107/S205698901402564X
    In the title compound, C12H15IO7, the 3,4-di-hydro-2H-pyran ring is in a distorted half-boat conformation with the atom bearing the acet-yloxy group adjacent to the C atom bearing the methyl-acetate group lying 0.633 (6) Å above the plane of the remaining ring atoms (r.m.s. deviation = 0.0907 Å). In the crystal, mol-ecules are linked into a supra-molecular chain along the a axis through two C-H⋯O inter-actions to the same acceptor carbonyl O atom; these chains pack with no specific inter-molecular inter-actions between them.
    Matched MeSH terms: Acetates
  3. Fulltext Crystal structure, DFT study and Hirshfeld surface analysis of ethyl 6-chloro-2-eth-oxy-quinoline-4-carboxyl-ate
    Bouzian Y, Karrouchi K, Anouar EH, Bouhfid R, Arshad S, Essassi EM
    Acta Crystallogr E Crystallogr Commun, 2019 Jun 01;75(Pt 6):912-916.
    PMID: 31391993 DOI: 10.1107/S2056989019007473
    In the title quinoline derivative, C14H14ClNO3, there is an intra-molecular C-H⋯O hydrogen bond forming an S(6) graph-set motif. The mol-ecule is essentially planar with the mean plane of the ethyl acetate group making a dihedral angle of 5.02 (3)° with the ethyl 6-chloro-2-eth-oxy-quinoline mean plane. In the crystal, offset π-π inter-actions with a centroid-to-centroid distance of 3.4731 (14) Å link inversion-related mol-ecules into columns along the c-axis direction. Hirshfeld surface analysis indicates that H⋯H contacts make the largest contribution (50.8%) to the Hirshfeld surface.
    Matched MeSH terms: Acetates
  4. Fulltext Synthesis and characterization of some new 4-hydroxy-coumarin derivatives
    Al-Majedy YK, Kadhum AA, Al-Amiery AA, Mohamad AB
    Molecules, 2014 Aug 07;19(8):11791-9.
    PMID: 25105917 DOI: 10.3390/molecules190811791
    Some novel coumarins were synthesized starting from 4-hydroxycoumarin and methyl bromoacetate. The structures of the newly obtained compounds were confirmed by elemental analysis, mass, IR and NMR spectra.
    Matched MeSH terms: Acetates/chemical synthesis; Acetates/chemistry*
  5. The study of dipole moment of some substituted acetic acids in an electronically excited state
    Murthy MB, Daya Sagar BS, Patil RL
    Spectrochim Acta A Mol Biomol Spectrosc, 2003 Apr;59(6):1277-80.
    PMID: 12659896
    The electronic absorption spectra of eight substituted acetic acids have been measured at room temperature in several solvents. The ground state dipole moments are evaluated experimentally for these molecules. These ground state values are used in conjunction with the spectral results to evaluate their first electronically excited state dipole moments. For all the molecules investigated here the dipole moments in the excited state are higher than their ground state values.
    Matched MeSH terms: Acetates/analysis; Acetates/chemistry*
  6. Strength characteristics of aerobic granular sludge
    Nor-Anuar A, Ujang Z, van Loosdrecht MC, de Kreuk MK, Olsson G
    Water Sci Technol, 2012;65(2):309-16.
    PMID: 22233910 DOI: 10.2166/wst.2012.837
    Aerobic granular sludge has a number of advantages over conventional activated sludge flocs, such as cohesive and strong matrix, fast settling characteristic, high biomass retention and ability to withstand high organic loadings, all aspects leading towards a compact reactor system. Still there are very few studies on the strength of aerobic granules. A procedure that has been used previously for anaerobic granular sludge strength analysis was adapted and used in this study. A new coefficient was introduced, called a stability coefficient (S), to quantify the strength of the aerobic granules. Indicators were also developed based on the strength analysis results, in order to categorize aerobic granules into three levels of strength, i.e. very strong (very stable), strong (stable) and not strong (not stable). The results indicated that aerobic granules grown on acetate were stronger (high density: >150 g T SSL(-1) and low S value: 5%) than granules developed on sewage as influent. A lower value of S indicates a higher stability of the granules.
    Matched MeSH terms: Acetates/metabolism
  7. Adsorption of butyl acetate in air over silver-loaded Y and ZSM-5 zeolites: experimental and modelling studies
    Bhatia S, Abdullah AZ, Wong CT
    J Hazard Mater, 2009 Apr 15;163(1):73-81.
    PMID: 18649998 DOI: 10.1016/j.jhazmat.2008.06.055
    Adsorption behaviours of butyl acetate in air have been studied over silver-loaded Y (Si/Al=40) and ZSM-5 (Si/Al=140) zeolites. The silver metal was loaded into the zeolites by ion exchange (IE) and impregnation (IM) methods. The adsorption study was mainly conducted at a gas hourly space velocity (GHSV) of 13,000 h(-1) with the organic concentration of 1000 ppm while the desorption step was carried out at a GHSV of 5000 h(-1). The impregnated silver-loaded adsorbents showed lower uptake capacity and shorter breakthrough time by about 10 min, attributed to changes in the pore characteristics and available surface for adsorption. Silver exchanged Y (AgY(IE)) with lower hydrophobicity showed higher uptake capacity of up to 35%, longer adsorbent service time and easier desorption compared to AgZSM-5(IE). The presence of water vapour in the feed suppressed the butyl acetate adsorption of AgY(IE) by 42% due to the competitive adsorption of water on the surface and the effect was more pronounced at lower GHSV. Conversely, the adsorption capacity of AgZSM-5(IE) was minimally affected, attributed to the higher hydrophobicity of the material. A mathematical model is proposed to simulate the adsorption behaviour of butyl acetate over AgY(IE) and AgZSM-5(IE). The model parameters were successfully evaluated and used to accurately predict the breakthrough curves under various process conditions with root square mean errors of between 0.05 and 0.07.
    Matched MeSH terms: Acetates/chemistry*
  8. Mobility Studies of (14)C-Chlorpyrifos in Malaysian Oil Palm Soils
    Halimah M, Ismail BS, Nashriyah M, Maznah Z
    Bull Environ Contam Toxicol, 2016 Jan;96(1):120-4.
    PMID: 26546229 DOI: 10.1007/s00128-015-1685-3
    The mobility of (14)C-chlorpyrifos using soil TLC was investigated in this study. It was found that chlorpyrifos was not mobile in clay, clay loam and peat soil. The mobility of (14)C-chlorpyrifos and non-labelled chlorpyrifos was also tested with silica gel TLC using three types of developing solvent hexane (100%), hexane:ethyl acetate (95:5, v/v); and hexane:ethyl acetate (98:2, v/v). The study showed that both the (14)C-labelled and non-labelled chlorpyrifos have the same Retardation Factor (Rf) for different developing solvent systems. From the soil column study on mobility of chlorpyrifos, it was observed that no chlorpyrifos residue was found below 5 cm depth in three types of soil at simulation rainfall of 20, 50 and 100 mm. Therefore, the soil column and TLC studies have shown similar findings in the mobility of chlorpyrifos.
    Matched MeSH terms: Acetates
  9. Diacetatobis(trimethylenethiourea)zinc(II) monohydrate
    Razak IA, Usman A, Fun HK, Yamin BM, Keat GW
    Acta Crystallogr C, 2002 Jan;58(Pt 1):m31-3.
    PMID: 11781464
    In the title compound, [Zn(CH3COO)2(C4H8N2S)2]*H2O, the Zn atom is tetrahedrally coordinated in the ZnO2S2 form. N-H...O and O-H...O intramolecular and intermolecular hydrogen bonds are formed by the four N atoms and the water molecule. N-H...O intermolecular hydrogen bonds and C-H...S and C-H...O intermolecular interactions interconnect columns formed by the molecules into layers. Adjacent layers are then linked by other N-H...O and O-H...O intermolecular hydrogen bonds to form a three-dimensional framework throughout the structure. The orientations of the acetate planes are such that the Zn atom lies within them.
    Matched MeSH terms: Acetates
  10. Fulltext Montelukast in children with allergic rhinitis amid COVID-19 pandemic
    Kow CS, Hasan SS
    Acta Paediatr, 2020 10;109(10):2151.
    PMID: 32686128 DOI: 10.1111/apa.15491
    Matched MeSH terms: Acetates
  11. Fulltext Exhaustive extraction of compounds from pomegranate peel and flesh using solvents of varying polarity
    Idris Aliyu Massaud, Atif Amin Baig, Mohd Adzim Khalili Rohin
    Asian Journal of Medicine and Biomedicine, 2018;1(1):10-13.
    MyJurnal
    Pomegranate fruit is the most studied part of punica granatum shrub. The fruit contains enormous
    amount of polyphenol compounds in the peel and arils (flesh) which are responsible for its antioxidant
    activity. The polyphenols present are of varying degree of lipophilicity and thus would require solvents
    of varying polarity to extract them. In this study, the effects of solvent type and homogenisation on
    extraction yield were considered. The fruit was first separated into peel and flesh and subsequently, one
    half of each of the peel and flesh were separately homogenised. Ethanol, ethylacetate and hexane were
    used to extract the polyphenol content of each of the four samples; non-homogenised peel (NP), nonhomogenised flesh (NF), homogenised peel (HP) and homogenised flesh (HF) in decreasing order of
    polarity using maceration method. The extraction was carried out successively using the residue
    recovered from previous extraction. Ethanol was used for a second time to complete the extraction
    process. The total extractive yield from the four samples were 27.19, 26.04, 25.03 and 15.61 for HP,
    NP, HF and NF respectively. The experiment has demonstrated that maceration process can be used to
    extract compounds from pomegranate to give a yield similar to more sophisticated method and ethanol
    is a suitable solvent for extracting hydrophilic compounds from the fruit.
    Matched MeSH terms: Acetates
  12. Fulltext The use of umbelliferone in the synthesis of new heterocyclic compounds
    Al-Amiery AA, Musa AY, Kadhum AA, Mohamad AB
    Molecules, 2011 Aug 10;16(8):6833-43.
    PMID: 21832973 DOI: 10.3390/molecules16086833
    New coumarin derivatives, namely 7-[(5-amino-1,3,4-thiadiazol-2-yl)methoxy]-2H-chromen-2-one, 5-[(2-oxo-2H-chromen-7-yloxy)methyl]-1,3,4-thiadiazol-2(3H)-one, 2-[2-(2-oxo-2H-chromen-7-yloxy)acetyl]-N-phenylhydrazinecarbothioamide, 7-[(5-(phenylamino)-1,3,4-thiadiazol-2-yl)methoxy]-2H-chromen-2-one and 7-[(5-mercapto-4-phenyl-4H-1,2,4-triazol-3-yl)methoxy]-2H-chromen-2-one were prepared starting from the natural compound umbelliferone. The newly synthesized compounds were characterized by elemental analysis and spectral studies (IR, ¹H-NMR and ¹³C-NMR).
    Matched MeSH terms: Acetates/chemistry
  13. Optimization of air-borne butyl acetate adsorption on dual-function Ag-Y adsorbent-catalyst using response surface methodology
    Bhatia S, Wong CT, Abdullah AZ
    J Hazard Mater, 2009 May 30;164(2-3):1110-7.
    PMID: 18976860 DOI: 10.1016/j.jhazmat.2008.09.040
    The low concentration and high flow rate of air-borne butyl acetate (BA) could be effectively removed using combined adsorption-catalytic oxidation system. Ag-Y (Si/Al=80) dual-function adsorbent was investigated for the adsorption step of 1000 ppm of butyl acetate at gas hourly space velocity of 13,000 h(-1) at ambient temperature under dry and humid feeds. A central composite design (CCD) coupled with response surface methodology (RSM) was employed to obtain the optimum process conditions and the interactions between process variables were demonstrated and elucidated. Humidity and increasing organic concentration shortened the adsorption service time. The effect of moisture was more pronounced at low BA concentration. The interactions between the BA concentration and humidity were statistically significant at 95% confidence level. The optimum conditions were found to be at 4500 ppm of BA with 37 min saturation time to give 58 mg BA/g as adsorption capacity. The simulated data fitted the experimental data satisfactorily. The simulated data also correctly demonstrated the overall behaviors of the adsorption process.
    Matched MeSH terms: Acetates/isolation & purification*
  14. Catalytic oxidation of butyl acetate over silver-loaded zeolites
    Wong CT, Abdullah AZ, Bhatia S
    J Hazard Mater, 2008 Sep 15;157(2-3):480-9.
    PMID: 18294771 DOI: 10.1016/j.jhazmat.2008.01.012
    The performance of silver-loaded zeolite (HY and HZSM-5) catalysts in the oxidation of butyl acetate as a model volatile organic compound (VOC) was studied. The objective was to find a catalyst with superior activity, selectivity towards deep oxidation product and stability. The catalyst activity was measured under excess oxygen condition in a packed bed reactor operated at gas hourly space velocity (GHSV)=15,000-32,000 h(-1), reaction temperature between 150 and 500 degrees C and butyl acetate inlet concentration of 1000-4000 ppm. Both AgY and AgZSM-5 catalysts exhibited high activity in the oxidation of butyl acetate. Despite lower silver content, AgY showed better activity, attributed to better metal dispersion, surface characteristics and acidity, and its pore system. Total conversion of butyl acetate was achieved at above 400 degrees C. The oxidation of butyl acetate followed a simple power law model. The reaction orders, n and m were evaluated under differential mode by varying the VOC partial pressure between 0.004 and 0.018 atm and partial pressure of oxygen between 0.05 and 0.20 atm. The reaction rate was independent of oxygen concentration and single order with respect to VOC concentration. The activation energies were 19.78 kJ/mol for AgY and 32.26 kJ/mol for AgZSM-5, respectively.
    Matched MeSH terms: Acetates/chemistry*
  15. A geranylacetophenone from the leaves of Melicope ptelefolia
    Shaari K, Safri S, Abas F, Lajis NH, Israf DA
    Nat Prod Res, 2006 May 10;20(5):415-9.
    PMID: 16644538
    The leaves of Melicope ptelefolia (Rutaceae) afforded a new acetophenone named 2,4,6-trihydroxy-3-geranylacetophenone. The structure of the compound was established by mass and NMR spectroscopy.
    Matched MeSH terms: Acetates/chemistry
  16. Method development for determination of fluroxypyr in soil
    Halimah M, Tan YA, Ismail BS
    J Environ Sci Health B, 2004;39(5-6):765-77.
    PMID: 15620085
    Four methods were developed for the analysis of fluroxypyr in soil samples from oil palm plantations. The first method involved the extraction of the herbicide with 0.05 M NaOH in methanol followed by purification using acid base partition. The concentrated material was subjected to derivatization and then cleaning process using a florisil column and finally analyzed by gas chromatography (GC) equipped with electron capture detector (ECD). By this method, the recovery of fluroxypyr from the spiked soil ranged from 70 to 104% with the minimum detection limit at 5 microg/kg. The second method involved solid liquid extraction of fluroxypyr using a horizontal shaker followed by quantification using high performance liquid chromatography (HPLC) equipped with UV detector. The recovery of fluroxypyr using this method, ranged from 80 to 120% when the soil was spiked with fluroxypyr at 0.1-0.2 microg/g soil. In the third method, the recovery of fluroxypyr was determined by solid liquid extraction using an ultrasonic bath. The recovery of fluroxypyr at spiking levels of 4-50 microg/L ranged from 88 to 98% with relative standard deviations of 3.0-5.8% with a minimum detection limit of 4 microg/kg. In the fourth method, fluroxypyr was extracted using the solid liquid extraction method followed by the cleaning up step with OASIS HLB (polyvinyl dibenzene). The recovery of fluroxypyr was between 91 and 95% with relative standard deviations of 4.2-6.2%, respectively. The limit of detection in method 4 was further improved to 1 pg/kg. When the weight of soil used was increased 4 fold, the recovery of fluroxypyr at spiking level of 1-50 microg/kg ranged from 82-107% with relative standard deviations of 0.5-4.7%.
    Matched MeSH terms: Acetates/analysis*
  17. Effects of different carbon sources on enhanced biological phosphorus removal and "Candidatus Accumulibacter" community composition under continuous aerobic condition
    Nittami T, Mukai M, Uematsu K, Yoon LW, Schroeder S, Chua ASM, et al.
    Appl Microbiol Biotechnol, 2017 Dec;101(23-24):8607-8619.
    PMID: 29063174 DOI: 10.1007/s00253-017-8571-3
    Previous studies have shown that enhanced biological phosphorus removal (EBPR) performance under continuous aerobic conditions always eventually deteriorates; however, the speed at which this happens depends on the carbon source supplied. The published data suggest that propionate is a better carbon source than acetate is for maintaining operational stability, although it is not clear why. A lab-scale sequencing batch reactor was run initially under conventional anaerobic/aerobic conditions with either acetate or propionate as the carbon source. Chemical and microbiological analyses revealed that both sources performed as expected for such systems. When continuous aerobic conditions were imposed on both these established communities, marked shifts of the "Candidatus Accumulibacter" clades were recorded for both carbon sources. Here, we discuss whether this shift could explain the prolonged EBPR stability observed with propionate.
    Matched MeSH terms: Acetates/metabolism
  18. Fulltext Transcriptomic and proteomic profiling revealed reprogramming of carbon metabolism in acetate-grown human pathogen Candida glabrata
    Chew SY, Brown AJP, Lau BYC, Cheah YK, Ho KL, Sandai D, et al.
    J Biomed Sci, 2021 Jan 02;28(1):1.
    PMID: 33388061 DOI: 10.1186/s12929-020-00700-8
    BACKGROUND: Emergence of Candida glabrata, which causes potential life-threatening invasive candidiasis, has been widely associated with high morbidity and mortality. In order to cause disease in vivo, a robust and highly efficient metabolic adaptation is crucial for the survival of this fungal pathogen in human host. In fact, reprogramming of the carbon metabolism is believed to be indispensable for phagocytosed C. glabrata within glucose deprivation condition during infection.

    METHODS: In this study, the metabolic responses of C. glabrata under acetate growth condition was explored using high-throughput transcriptomic and proteomic approaches.

    RESULTS: Collectively, a total of 1482 transcripts (26.96%) and 242 proteins (24.69%) were significantly up- or down-regulated. Both transcriptome and proteome data revealed that the regulation of alternative carbon metabolism in C. glabrata resembled other fungal pathogens such as Candida albicans and Cryptococcus neoformans, with up-regulation of many proteins and transcripts from the glyoxylate cycle and gluconeogenesis, namely isocitrate lyase (ICL1), malate synthase (MLS1), phosphoenolpyruvate carboxykinase (PCK1) and fructose 1,6-biphosphatase (FBP1). In the absence of glucose, C. glabrata shifted its metabolism from glucose catabolism to anabolism of glucose intermediates from the available carbon source. This observation essentially suggests that the glyoxylate cycle and gluconeogenesis are potentially critical for the survival of phagocytosed C. glabrata within the glucose-deficient macrophages.

    CONCLUSION: Here, we presented the first global metabolic responses of C. glabrata to alternative carbon source using transcriptomic and proteomic approaches. These findings implicated that reprogramming of the alternative carbon metabolism during glucose deprivation could enhance the survival and persistence of C. glabrata within the host.

    Matched MeSH terms: Acetates/metabolism
  19. Fulltext Crystal structure of 1-benzyl-2-hy-droxy-5-oxopyrrolidin-3-yl acetate
    Caracelli I, Zukerman-Schpector J, Stefani HA, Ali B, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2015 Aug 1;71(Pt 8):o582-3.
    PMID: 26396808 DOI: 10.1107/S2056989015013353
    In the title compound, C13H15NO4, the oxopyrrolidin-3-yl ring has an envelope conformation, with the C atom bearing the acetate group being the flap. The acetate and phenyl groups are inclined with respect to the central ring, forming dihedral angles of 50.20 (12) and 87.40 (9)°, respectively, with the least-squares plane through the ring. The dihedral angle between the acetate group and the phenyl ring is 63.22 (8)°, indicating a twisted conformation in the mol-ecule. In the crystal, supra-molecular chains along the b axis are formed by (hy-droxy)O-H⋯O(ring carbon-yl) hydrogen bonds. The chains are consolidated into the three-dimensional architecture by C-H⋯O inter-actions.
    Matched MeSH terms: Acetates
  20. Racemic mefloquinium chloro-difluoro-acetate: crystal structure and Hirshfeld surface analysis
    Wardell JL, Wardell SMSV, Jotani MM, Tiekink ERT
    Acta Crystallogr E Crystallogr Commun, 2018 Jul 01;74(Pt 7):895-900.
    PMID: 30002881 DOI: 10.1107/S2056989018007703
    In the racemic title mol-ecular salt, C17H17F6N2O+·C2ClF2O3- (systematic name: 2-{[2,8-bis-(tri-fluoro-meth-yl)quinolin-4-yl](hy-droxy)meth-yl}piperidin-1-ium chloro-difluoro-acetate), the cation, which is protonated at the piperidine N atom, has the shape of the letter, L, with the piperidin-1-ium group being approximately orthogonal to the quinolinyl residue [the Cq-Cm-Cm-Na (q = quinolinyl; m = methine; a = ammonium) torsion angle is 177.79 (18)°]. An intra-molecular, charge-assisted ammonium-N-H⋯O(hydrox-yl) hydrogen bond ensures the hy-droxy-O and ammonium-N atoms lie to the same side of the mol-ecule [Oh-Cm-Cm-Na (h = hydrox-yl) = -59.7 (2)°]. In the crystal, charge-assisted hydroxyl-O-H⋯O-(carboxyl-ate) and ammonium-N+-H⋯O-(carboxyl-ate) hydrogen bonds generate a supra-molecular chain along [010]; the chain is consolidated by C-H⋯O inter-actions. Links between chains to form supra-molecular layers are of the type C-Cl⋯π(quinolinyl-C6) and the layers thus formed stack along the a-axis direction without directional inter-actions between them. The analysis of the calculated Hirshfeld surface points to the dominance of F⋯H contacts to the surface (40.8%) with significant contributions from F⋯F (10.5%) and C⋯F (7.0%) contacts.
    Matched MeSH terms: Acetates
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