scholarly journals Organo(organooxo)mercury(II) chemistry — Synthesis and structure of methyl(phenoxo)mercury(II)

2006 ◽  
Vol 84 (2) ◽  
pp. 77-80 ◽  
Author(s):  
Allan J Canty ◽  
Janette W Devereux ◽  
Brian W Skelton ◽  
Allan H White
Keyword(s):  
Key Words ◽  
Spectroscopic Studies ◽  
Key Words Mercury

Methyl(phenoxo)mercury(II) may be obtained from the reaction of methyl(chloro)mercury(II) with silver(I) oxide, followed by addition of phenol. The dominant motif of the structure is a pair of independent MeHgOPh aggregates (Hg—C,O 2.05(2) Å, 2.06(1) Å (x2); C-Hg-O 176.6(5)°, 176.3(5)°) loosely associated about a quasi-inversion centre by Hg···O interactions (2.702(9) Å, 2.719(9) Å) to form a dimer (Hg-O-Hg′ 106.0(4)°, 106.5(4)°; O-Hg-O′ 73.0(3)°, 72.6(3)°), the dimer stacking up the short crystallographic c axis (= 6.914(1) Å) at spacings c/2. Vibrational spectroscopic studies are insensitive to the associative interactions. Key words: mercury, methylmercury, organomercury, structure, aryloxide, phenoxide.

scholarly journals Investigations on Terminalia Arjuna Fruits: Part 1- Isolation of Comounds from Petroleum Ether Fractions

1970 ◽  
Vol 43 (1) ◽  
pp. 123-130 ◽  
Author(s):  
M Zahurul Haque ◽  
M Abdullah As Saki ◽  
M Umar Ali ◽  
M Yusuff Ali
Keyword(s):  
Petroleum Ether ◽  
Key Words ◽  
1H Nmr ◽  
13C Nmr ◽  
Chromatographic Separation ◽  
Spectroscopic Studies ◽  
Biologically Active ◽  
Terminalia Arjuna ◽  
Pure Compounds ◽  
Column Chromatographic

Arjun (Terminalia arjuna) is a source of many potent, biologically active compounds, planned all over Bangladesh. The chemical examinations of its fruits were taken up to isolate and identify active principles. For this purpose fresh fruits of Terminalia arjuna were extracted with rectified spirit. The extract was then triturated with petroleum ether (40-60°C), which was then subjected to column chromatographic separation followed by PTLC. Such separation led to the isolation of some new pure compounds, TA-1 to TA-5. The structures of compounds were characterized through spectroscopic studies (IR, 1H-NMR and 13C-NMR). Key words: Arjun, TA-1, TA-5, Spectroscopic studies DOI: 10.3329.bjsir.v43i1.863 Bangladesh J. Sci. Ind. Res. 43(1),123-130, 2008

Oleanane Glycosides from Eclipta prostrata

1970 ◽  
Vol 4 (2) ◽  
Author(s):  
Mohammad S Rahman ◽  
Rasheduzzaman Chowdhury ◽  
Chodhury M Hasan ◽  
Mohammad A Rashid
Keyword(s):  
Key Words ◽  
13C Nmr ◽  
Full Text ◽  
High Field ◽  
Stem Bark ◽  
Spectroscopic Studies ◽  
Hexane Extract ◽  
Nmr Data ◽  
Eclipta Prostrata ◽  
First Time

Two oleanane-type glycosides eclalbasaponin II (1) and eclalbasaponin I (2) along with the ubiquitous steroid, stigmasterol were isolated from an n-hexane extract of the stem bark of Eclipta prostrata. The structures of the isolated compounds were confirmed by extensive spectroscopic studies, notably high field NMR and MS. The 13C NMR data of the parent saponins 1 and 2 are reported here for the first time. Key words: Eclipta prostrata, Compositae, Oleanane glycoside, Eclalbasaponin I, Eclalbasaponin II. Dhaka Univ. J. Pharm. Sci. Vol.4(2) 2005 The full text is of this article is available at the Dhaka Univ. J. Pharm. Sci. website

scholarly journals Terpenoids and Coumarin from Bursera serrata Wall.

1970 ◽  
Vol 8 (2) ◽  
pp. 107-110 ◽  
Author(s):  
Kulsum Ara ◽  
Mohammad S Rahman ◽  
AHMM Rahman ◽  
Choudhury M Hasan ◽  
Mohammad A Rashid
Keyword(s):  
Antimicrobial Activity ◽  
Petroleum Ether ◽  
Key Words ◽  
Plant Species ◽  
Stem Bark ◽  
Spectroscopic Studies ◽  
Published Data ◽  
First Report

Two terpenoids, β-amyrin (1) and β-sitostenone (2) and a coumarin, scopoletin (3) were isolated from petroleum ether and dichloromethane soluble extracts of the stem bark of Bursera serrata Wall. The structures of the isolated compounds 1-3 were established by extensive spectroscopic studies as well as by comparison with published data. Although compounds 1-3 have been isolated from various plant species previously, this is the first report of the occurrence of these compounds from B. serrata. The crude extractives exhibited weak antimicrobial activity and cytotoxicity. Key words: Bursera serrata; Burseraceae; β-amyrin; β-sitostenone; scopoletin; antimicrobial; cytotoxicity   DOI: 10.3329/dujps.v8i2.6023 Dhaka Univ. J. Pharm. Sci. 8(2): 107-110, 2009 (December)

Kinetic and spectroscopic studies on α- and β-cyclodextrin rotaxanes with (µ-N,N′- bis(4-pyridinylmethylene)-α,ω-alkanediimine)bis[pentacyanoferrate(II)] threads

2005 ◽  
Vol 83 (3) ◽  
pp. 195-201 ◽  
Author(s):  
Victor X Jin ◽  
Donal H Macartney ◽  
Erwin Buncel
Keyword(s):  
Chemical Shift ◽  
Metal Complexes ◽  
Key Words ◽  
Rate Constants ◽  
Self Assembly ◽  
Spectroscopic Studies ◽  
Ligand Substitution ◽  
H Nmr ◽  
End Groups ◽  
The Stability

[2]Pseudorotaxanes have been prepared by threading N,N′-bis(4-pyridinylmethylene)-1,2-ethanediimine (L2), -1,4-butanediimine (L4), and -1,6-hexanediimine (L6) ligands through α-cyclodextrin (α-CD) and β-cyclodextrin (β-CD), and have subsequently been converted to the corresponding [2]rotaxane species by coordinating bulky [Fe(CN)5]3– end groups. The stability constants for the [2]pseudorotaxanes were determined by 1H NMR chemical shift titrations and increase with the polymethylene chain length n. The rate constants for both the formation of the [Fe(CN)5(Ln)]3– complexes from the [Fe(CN)5OH2]3– ion and Ln, and the rate constants for the dissociation of Ln from the metal complexes, exhibit significant diminutions in the presence of α- and β-CD, owing to inclusions of the free and coordinated ligands, respectively. The lability of the iron(II)–pyridine bonds also permits the spontaneous self-assembly of the [2]rotaxane upon the addition of cyclodextrin to the iron dimer complexes. The mechanism for this process involves the rate-determining dissociation of a [Fe(CN)5]3– unit from [(NC)5Fe(Ln)Fe(CN)5]6–, followed by CD inclusion of the Ln ligand to form a semirotaxane, and subsequent recomplexation by the [Fe(CN)5OH2]3– ion. Key words: cyclodextrins, rotaxanes, pentacyanoferrate(II), ligand substitution, kinetics.

Phytochemical Studies of Amoora cucullata

1970 ◽  
Vol 4 (1) ◽  
Author(s):  
Mohammad S Rahman ◽  
Rasheduzzaman Chowdhury ◽  
Bilkis Begum ◽  
Khondaker M Rahman ◽  
Mohammad A Rashid
Keyword(s):  
Key Words ◽  
Caffeic Acid ◽  
Betulinic Acid ◽  
Full Text ◽  
High Field ◽  
Stem Bark ◽  
Spectroscopic Studies ◽  
Hexane Extract ◽  
First Report ◽  
Phytochemical Studies

Five compounds were isolated from a hexane extract of the stem bark of Amoora cucullata. The structures of the isolated compounds were established as fridelin (1), stigmasterol, β-sitosterol, betulinic acid (2) and caffeic acid (3) by extensive spectroscopic studies, including high field NMR and MS analyses. This is the first report of occurrence of these compounds from A. cucullata. Key words: Amoora cucullata, Meliaceae, Fridelin, Betulinic acid, Caffeic acid, β-Sitosterol, Stigmasterol Dhaka Univ. J. Pharm. Sci. Vol.4(1) 2005 The full text is of this article is available at the Dhaka Univ. J. Pharm. Sci. website

Modified method of synthesis of N-substituted dithioesters of amino acids and peptides in the Pinner reaction

1996 ◽  
Vol 74 (3) ◽  
pp. 341-343 ◽  
Author(s):  
Witold Neugebauer ◽  
Eric Pinet ◽  
Munsok Kim ◽  
Paul R. Carey
Keyword(s):  
Amino Acids ◽  
Key Words ◽  
Hydrogen Fluoride ◽  
Resonance Raman ◽  
Spectroscopic Studies ◽  
Hf Isotopes ◽  
Improved Method ◽  
Model Compounds ◽  
Raman Spectroscopic ◽  
Modified Method

An improved method for the synthesis of dithioesters of amino acids and peptides has been developed. The syntheses have been carried out from the nitriles. The addition of thiol to the nitrile derivative in the Pinner step of dithioester synthesis was activated with hydrogen fluoride. A few examples of dithioester synthesis using liquid HF are described. Some novel dithioesters, which are model compounds for resonance Raman spectroscopic studies of dithioacylpapain intermediates, are described. Key words: dithioesters, amino acids, Pinner reaction, HF, isotopes.

scholarly journals Secondary Metabolites from Sterespermum chelonoides

1970 ◽  
Vol 4 (1) ◽  
Author(s):  
Mohammad R Haque ◽  
Khondaker M Rahman ◽  
Bilkis Begum ◽  
Choudhury M Hasan ◽  
Mohammad A Rashid
Keyword(s):  
Secondary Metabolites ◽  
Key Words ◽  
Full Text ◽  
High Field ◽  
Methanolic Extract ◽  
Stem Bark ◽  
Spectroscopic Studies ◽  
First Report

Five compounds namely, sterekunthal B (1), sterequinone C (2), p-hydroxybenzaldehyde (3), p-hydroxyphenylmethyl ketone (4) and stigmasterol (5) were isolated from methanolic extract of the stem bark of Stereospermum chelonoides. The structures of compounds 1-5 were established by extensive spectroscopic studies, notably high field NMR and MS. This is the first report of occurrence of 1-5 from Stereospermum chelonoides. Key words: Stereospermum chelonoides, Bignoniaceae, Sterekunthal B, Sterequinone C Dhaka Univ. J. Pharm. Sci. Vol.4(1) 2005 The full text is of this article is available at the Dhaka Univ. J. Pharm. Sci. website

SEASONAL CHANGES IN BACKGROUND LEVELS OF MERCURY IN SURFACE HORIZONS OF FORESTED SOILS IN ALBERTA

1983 ◽  
Vol 63 (2) ◽  
pp. 397-400 ◽  
Author(s):  
M. J. DUDAS ◽  
K. CANNON
Keyword(s):  
Heavy Metal ◽  
Key Words ◽  
Seasonal Changes ◽  
Organic Soil ◽  
Early Spring ◽  
Mercury Cycling ◽  
Soil Horizons ◽  
Background Levels ◽  
Key Words Mercury

Content of mercury in organic soil horizons was monitored to ascertain seasonal changes in background levels. L, F, and H horizons were relatively enriched in mercury in early spring. Levels then diminished and reached seasonal low values in August. Content of mercury then increased twofold during September after which levels declined to summer values. F horizons had the highest content of mercury and H horizons had the lowest. Key words: Mercury cycling, mercury dynamics, heavy metal

scholarly journals Investigations on Terminalia arjuna Fruits: Part 2- Isolation of Compound from ethyl Acetate Fraction

1970 ◽  
Vol 43 (2) ◽  
pp. 283-290
Author(s):  
M Zahurul Haque ◽  
M Abdullah As Saki ◽  
M Umar Ali ◽  
M Yusuff Ali ◽  
M Abdullah-Al Maruf
Keyword(s):  
Ethyl Acetate ◽  
Key Words ◽  
Chromatographic Separation ◽  
Ethyl Acetate Fraction ◽  
Spectroscopic Studies ◽  
Terminalia Arjuna ◽  
Isolation And Purification ◽  
Traditional Medicines ◽  
Chemical Studies ◽  
Column Chromatographic

Arjun (Terminalia arjuna) is used in traditional medicines for the treatment of various diseases (Ahmed, 2002). The phyto-chemical studies shows that the plant contains active and medicinal principles like glycosides, alkaloids, steroids, tennins etc (Ahmed, 2002). The chemical examinations of its fruits were taken up to isolate and identify active principles. For this purpose fresh fruits of Terminalia arjuna were extracted with rectified spirit. The extract was then triturated with ethyl acetate, which was then subjected to column chromatographic separation followed by PTLC. Such separation led to the isolation and purification of compound, sitosteryl-3-o-ß-Dglucoside. The structure of compound was characterized by IR, 1H-NMR and 13CNMR spectroscopic studies. Key words : Arjun, Phyto-chemical studies, Sitosteryl, Glucosidy, Chromatographic separation.DOI: 10.3329/bjsir.v43i2.974 Bangladesh J. Sci. Ind. Res. 43(2),283-290 , 2008

Decrease in Mercury Content of Fishes in Ball Lake, Ontario, Since Imposition of Controls on Mercury Discharges

1979 ◽  
Vol 36 (6) ◽  
pp. 670-672 ◽  
Author(s):  
F. A. J. Armstrong ◽  
D. P. Scott
Keyword(s):  
Key Words ◽  
White Muscle ◽  
Fork Length ◽  
Lake Ontario ◽  
Northern Pike ◽  
Mercury Content ◽  
Mercury Contamination ◽  
Coregonus Clupeaformis ◽  
Northwestern Ontario ◽  
Key Words Mercury

Weight, fork length, and white muscle mercury concentrations of walleye (Stizostedion vitreum vitreum), northern pike (Esox lucius), and lake whitefish (Coregonus clupeaformis) from Ball Lake, northwestern Ontario, were compared for 1971, 1972, and 1976. The lake had received mercury from 1962 to 1970; since then there have been increasingly rigorous controls. Adjusted mean white muscle mercury concentrations for walleye at the group mean length of 444 mm were 1.99, 2.71, and 1.39 mg/kg, respectively, for the three sample years. Corresponding values for pike 594 mm long were 5.05, 5.72, and 1.80 mg/kg. Whitefish values for 1972 and 1976 were 0.62 and 0.42 at 441 mm fork length. The changes are discussed in relation to the decreased input of mercury to the lake and it is suggested that mercury in suspension may be a controlling factor. Key words: mercury contamination, walleye, pike, whitefish, Ball Lake

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