Separation of99mTc from parent99Mo by solid-phase column extraction as a simple option for a new99mTc generator concept

Evidence is obtained to show that the liquidliquid extraction separation of^99mTc from⁹⁹Mo with methyl ethyl ketone, methyl propyl ketone and methyl isobutyl ketone can be transformed into a solid-phase column extraction procedure. The aqueous alkaline⁹⁹molybdate solution is immobilized on a column of a granular large-pore diatomaceous earch support, which is the neluted with the abovementioned extractants. Rapid and clean separation of^99mTc can be with all three solvents. The^99mTc can be back-extracted from the organic phase on a column filled with distilled water /or saline/ loaded granular diatomaceous earth /Extrelut^®/. The possibility of using the abovementioned procedure as a basis for a new^99mTc/⁹⁹Mo generator concept is envisaged.     

Chemical and radiochemical evaluation of the purity of99mTc extracted by MEK

Solvent extraction separation of^99mTc from⁹⁹Mo using methyl ethyl ketone(MEK) has been found to be an effective method of obtaining^99mTc of medicinal purity from low specific activity⁹⁹Mo. The authors have investigated the effect of alkali and molybdenum concentration on the extraction of⁹⁹Mo and^99mTc into methyl ethyl ketone. The possibility of methyl ethyl ketone forming enol and condensation products and its effect on the final extraction efficiency and purity of^99mTc has been studied. Sodium molybdate has been found to have a good salting out effect on^99mTc pertechnetate and hence^99mTc extraction can be better accomplished from low specific activity⁹⁹Mo solutions. The ketone seems to form traces of condensation products in the extraction procedure. These have been found to be coextracted with^99mTc into MEK but did not affect the extractability of^99mTc. It was observed that neutral alumina column removes these condensation products from MEK containing^99mTc. Alternately these could be filtered off by acidification of the final aqueous^99mTc solution. The studies indicate that under optimum experimental conditions methyl ethyl ketone separates^99mTc from⁹⁹Mo with high efficiency and yields^99mTc of high purity suitable for use in nuclear medicine in the form of various labelled compounds.     

Selective Deuterium Exchange of Pheny 1-2-Propanone

We required assymmetrically labelled phenyl-2-propanone for secondary deuterium isotope effect studies. While benzoyl acetone has been exchanged selectively at the methylene position,¹ attempts to deuterate phenyl-2-propanone selectively have failed.²,³ Since highly selective conditions for ketone exchange are not very common,⁴ I wish to report a very simple, mild, and convenient procedure for synthesizing PhCD₂COCH₃, and PhCH₂COCD₃ in high yield and isotopic purity.     

Determination of lead in the urine of exposed and unexposed adults by extraction and flow-injection/atomic absorption spectrometry

Lead is extracted from urine with ammonium pyrrolidien dithiocrbamate into methyl isobutyl ketone, and 20 μl of the extract is injected into a water carrier stream in a flow-injection/atomic absorption system. The procedure is simple, quick, accurate and reproducible. Recoveries are 96–105%. The mean urine lead contents of 20 unexposed and 20 printing-press lead exposed workers was found to be 39.0 ± 8.3 and 71.7 ± 26.3 μg Pb l^?1, respectively.     

Determination of riboflavin in pharmaceutical products by automatic discrete-sample analysis

A procedure for the determination of iron, copper, nickel, cobalt, manganese and chromium down to 0.01 μg g^-1 in sodium calcium silicate glass, sodium borosilicate glass, sodium carbonate and calcium carbonate is described. The analytical procedure depends on the separation at pH 6 of the metal diethyldithiocarbamates into isobutyl methyl ketone, and their determination by flameless atomic absorption spectrometry, with a Massmann-type graphite furnace. The limiting factors on the detection limits attainable are discussed and related to the purity of the acids used for sample solution, sample contamination during chemical separation and the sensitivity of the analytical technique.     

Chemo-enzymatic synthesis of isotopically labelled L-Valine,L-Isoleucine and allo-isoleucine

Syntheses of (3R)-[4,4,4-D₃]-L-valine, [¹⁵N]-L-isoleucine and [¹⁵N]-allo-isoleucine from homochiral 2-alkylated carboxylic acids are described. The approach involves a one-carbon homologation of the carboxylic acid to give the corrresponding β-substituted α-keto ester which is converted directly to the α-amino acid in a one-pot procedure involving two enzyme catalysed reactions (Candida cylindracea lipase to hydroluse the ester and leucine dehydrogenase to catalyse the reductive amination of the ketone). This strategy may be simply adapted for the selective labelling of each site of the L-amino acid.     

A Mild and Highly Efficient Synthesis of Chiral N‐Dichloroacetyl‐4‐ethyl‐1,3‐oxazolidines

Chiral 2‐amino‐butanols ( 4 and 5 ) were obtained via the isolation of diastereomeric salt. Then, chiral compounds ( 6 – 9) were synthesized by a sequential procedure involving condensation of chiral 2‐amino‐butanol with ketone and dichloroacetyl chloride. All the compounds were characterized by IR, ¹H NMR, ¹³C NMR, and element analysis. The absolute configurations of ( S )‐ 8 was determined by X‐ray crystallography.     

Structure and Properties of 2,2-Dibromovinyl Trifluoromethyl Ketone

It was established by IR spectroscopy and quantum-chemical calculations along nonempirical DFT method in B3LYP version with the basis set 6-311 G(d,p) that 2,2-dibromovinyl trifluoromethyl ketone consisted of a mixture of s-cis planar conformer and s-trans-form deviating from a plane by 13°, whereas the s-cis-form is more energetically stable than the s-trans one (E -5.07 kcal mol^{- 1}). Also in 2,2-dibromovinyl methyl ketone the planar s-cis conformer is more stable. Chlorine-containing analogs, 2,2-dichlorovinyl trifluoromethyl ketone and 2,2-dichlorovinyl methyl ketone, are more stable in the planar s-trans-conformation. Charge distribution and polarization in the dibromovinyl ketones are analogous to those in dichlorovinyl ketones in agreement with the established reactivity of dibromovinyl trifluoromethyl ketone. By reaction of 2,2-dibromovinyl trifluoromethyl ketone with 2,4-dinitrophenyl-, alkylhydrazines, N,N-dimethylhydrazine, N,N-, N,O-, N,S-binucleophiles were respectively obtained hydrazone, derivatives of pyrazole, imidazole, oxazole, and 1,3-thiazine containing a trifluoromethyl group.     

A short synthesis of 4-aryioxymethyl-δ3-chromenes and 3-(β-aryloxy)ethylbenzofurans

A direct and short route to the synthesis of 4-aryloxymethyl-δ³ -chromenes and 3-(β-aryloxy)-ethylbenzofurans is described. Hydration of I,4-diaryloxy-2-butynes with mercuric oxide and sulfuric acid affords, instead of a ketone, the cyclization product of the ketone. In three of the diaryloxy-butynes studied, the corresponding aryloxyethylbenzofurans are formed. In no instance could the ketone be isolated from the hydration reaction.     

Green chemistry approach to the synthesis of 2‐aryl‐4‐ferrocenyl‐quinoline derivatives under microwave irradiation

A clean and expeditious route for the synthesis of 2‐aryl‐4‐ferrocenyl‐quinoline derivatives through microwave‐assisted multicomponent reaction of ferrocenecarboxaldehyde with ketone and dimedone in the presence of ammonium acetate using water as reaction media at 100^°C is described. This procedure lends itself well to combinatorial methods, providing the target heteropolymetallic compounds in excellent yield. J. Heterocyclic Chem., (2011).     

PHOTOCHEMISTRY OF POLYFUNCTIONAL MOLECULES. DEVELOPMENT OF ANTENNA CHROMOPHORES FOR SELF-SENSITIZED PHOTOREDUCTION OF KETONES*

–Model systems are reported which test the efficacy of potential aryl antenna groups designed to harvest photons and subsequently transfer electronic energy to a target ketone through singlet-singlet energy transfer. The model series consists of 4-aryl substituted cyclohexanones where the aryl groups are benzyloxy ( 5a ), benzoyl ( 5b ), and dimethylphenylsiloxy ( 5c ). In each case, photolysis of isopropyl alcohol solutions of the substrate with 254 nm light results in photoreduction of the ketone to the corresponding alcohols, 6a-6c . The most efficacious sensitizing antennae are the benzyloxy and dimethylphenylsiloxy chromophores, with quantum efficiencies for reduction equal to 0.57 and 0.48, respectively. Photophysical and photochemical studies on 5a confirm that energy transfer to the ketone is intramolecular with the rate constant for energy transfer estimated at 2.4 × 10⁰ s^-1.     

Simultaneous determination of copper and lead by graphite-furnace atomic absorption spectrometry after liquid-liquid extraction of the ion pair with zephiramine

A procedure for the simultaneous determination of copper and lead by graphite-furnace atomic absorption spectrometry was investigated by means of a two-channel atomic absorption spectrometer. Both copper(II) and lead(II) are converted into their iodo complex anions and extracted quantitatively into diisobutyl ketone as their ion pairs with tetradecyldimethylbenzylammonium (zephiramine) in a 10-ml centrifuge tube. An aliquot of the organic extract is directly pipetted from the upper layer in the centrifuge tube and injected into the graphite furnace. The detection limits (S/N = 3) are 2.6 ng ml^?1 of copper and 1.0 ng ml^?1 of lead. The relative standard deviations for 10 replicate determinations are 2.9% for 20 ng ml^?1 of copper and 2.7% for 10 ng ml^?1 of lead. Results of analyses of some practical samples are given.     

Investigation of chromium(III) acetylacetonate as a calibration reference material for atomic absorption spectroscopy

It is shown that chromium(III) acetylacetonate meets the requirements of calibration reference materials: it is homogeneous, soluble in water and organic solvents, and its solutions are stable. Chromium(III) acetylacetonate has been successfully used as a calibration reference material in the analysis of chromium in iron-base alloys. The procedure involves chromium acetylacetonate extraction using methyl isobutyl ketone followed by direct atomic absorption analysis of the organic extract. The detection limit of the procedure is 10 ng g⁻¹. Correspondence: Konstantin Belikov, State Scientific Institution “Institute for Single Crystals” of the National Academy of Sciences of Ukraine, Kharkov, Ukraine     

Measurements of the kinetics of the OH‐initiated oxidation of methyl vinyl ketone and methacrolein

The mechanisms of the OH‐initiated oxidation of methyl vinyl ketone and methacrolein have been studied at 300 K and 100 Torr total pressure, using a turbulent flow technique coupled with laser‐induced fluorescence detection of the OH radical. The rate constants for the OH + methyl vinyl ketone and OH + methacrolein reactions were measured to be (1.78 ± 0.08) × 10^?11 and (3.22 ± 0.10) × 10^?11 cm³ molecule^?1 s^?1, respectively, and were found to be in excellent agreement with previous studies. In the presence of O₂ and NO, the OH radical propagation and the loss of OH through radical termination resulting from the production of methyl vinyl ketone‐ and methacrolein‐based alkyl nitrates were measured at 100 Torr total pressure and compared to the simulations of the kinetics of these reaction systems. The results of these experiments are consistent with an overall rate constant of (2.0 ± 1.3) × 10^?11 cm³ molecule^?1 s^?1 for both the methyl vinyl ketone‐based peroxy radical + NO and methacrolein‐based peroxy radical + NO reactions, each with branching ratios of 0.90 ± 0.10 for the bimolecular channel (oxidation of NO to NO₂) and 0.10 ± 0.10 for the termolecular channel (production of methyl vinyl ketone‐ and methacrolein‐based alkyl nitrates). © 2003 Wiley Periodicals, Inc. Int J Chem Kinet 36: 12–25, 2003     

Simple method of determination of copper,mercury and lead in potable water with preliminary pre-concentration by total reflection X-ray fluorescence spectrometry

Total reflection X-ray fluorescence spectrometry and chemical pre-concentration procedures have been applied for the analysis of trace concentrations of copper, mercury, and lead in drinking water samples. A simple total reflection module has been used in X-ray measurements. The elements under investigation were pre-concentrated by complexation using a mixture of carbamates followed by solvent extraction with methyl isobutyl ketone. The preconcentration procedure was tested with the use of twice-distilled water samples and samples of mineral and tap water spiked with known additions of copper, mercury, and lead. The obtained recovery and precision values are presented. The minimum detection limits for the determination of these elements in mineral and tap water samples were found to be 40 ng l⁻¹, 60 ng l⁻¹, and 60 ng l⁻¹, respectively.     

Comparative analysis of 13C shielding constants stereospecificity in the silicon and germanium derivatives of acetylenic aldehyde and ketone oximes based on the 13C NMR spectroscopy and GIAO calculations

In the acetylenic aldehyde oximes with substituents containing silicon and germanium, the ¹³C NMR signal of the C‐2 carbon of triple bond is shifted by 3.5 ppm to lower frequency and that of the C‐3 carbon is moved by 7 ppm to higher frequency on going from E to Z isomer. A greater low‐frequency effect of 5.5 ppm on the C‐2 carbon signal and a greater high‐frequency effect of 11 ppm on the C‐3 carbon signal are observed in the analogous acetylenic ketone oximes. The carbon chemical shift of the C?N bond is larger by 4 ppm in E isomer relative to Z isomer for the aldehyde and ketone oximes. The ²⁹Si chemical shifts in the silicon containing acetylenic aldehyde and ketone oximes are almost the same for the diverse isomers. The trends in changes of the measured chemical shifts are well reproduced by the gauge‐including atomic orbital (GIAO) calculations of the ¹³C and ²⁹Si shielding constants. Copyright © 2009 John Wiley & Sons, Ltd.     

Diarylcuprates for Selective Syntheses of Multifunctionalized Ketones from Thioesters under Mild Conditions

Ketones were selectively synthesized from thioesters by using diarylcuprates(I) generated in situ from copper(I) salts and aryl Grignard reagents in a 1 : 1.3–1.5 ratio under ambient temperature. During the ketone synthesis, various functional groups, such as carbonyl (ketones, esters, and amides), O-protecting groups, halogens, and heteroarenes, were tolerated to afford multifunctionalized ketones in excellent yields. This copper-mediated ketone synthesis could be applied to the synthesis of not only gluconolactone-derived ketone 6 , a synthetic intermediate in the transformation to the SGLT2 inhibitor canagliflozin, but also thiolactol 8 , a valuable synthetic intermediate for (+)-biotin. Control experiments on an isolated diphenylcuprate(I), [CuPh₂]⁻ ( 12 ), and DFT calculations revealed that this ketone synthesis proceeded by oxidative addition of the C−S bond of thioesters to [CuPh₂]⁻, while reductive elimination from the Cu^III intermediate produced the corresponding ketone and an inactive species [(RS)CuPh]⁻, the latter reacted with [CuPh]₄ ( 11 ) to regenerate the reactive diphenylcuprate(I).     

17O-NMR Spectra of Cyclopropenones and Tropone. Oxygen Exchange with Water

Whereas tropone ( 2 ) and a cyclopropanone 5 show rather normal ketone signals in their ¹⁷O-NMR spectra, the two cyclopropenones 1a , and lb exhibit exceptionally high shielding, indicating a structure closer to a ? O^? formula than to a ketone. For comparison, an enolate and several phenolates have been measured. In order to test the ketonic character, the nucleophilic addition of water was determined by the rate of isotopic O-exchange between ketone and water: 2 exchanged ca. 20 times slower than acetophenone, whereas la reacted very much more slowly.     

Chemical separation procedure for the nuclide analysis of a tantalum target irradiated for 500 days with 800 MeV protons

A rapid radiochemical separation procedure has been developed for the determination of long-lived and stable nuclides produced by spallation and activation in a tantalum target irradiated for 500 days with 800 MeV protons. In this procedure the matrix element tantalum and simultaneously the¹⁸²Ta activity, built-up by activation of the matrix with themalized spallation neutrons is removed from many elements. About 50 mg of the sample is dissolved in a mixture of concentrated nitric and hydrofluoric acid. After dilution tantalum is extracted with a solution of 0.2M tetrahexylammonium bromide in methyl isobutyl ketone (MIBK). The residual amount of tantalum and the remaining¹⁸²Ta activity are 0.0003% and the recoveries of 27 investigated elements are in the range of 96.0–99.9%. A further 22 elements are quantitatively separated according to their chemical behavior. In the final aqueous fraction the separated long-lived and stable nuclides of 49 elements can be measured with high sensitivity by -ray spectrometry and mass spectrometry (ICP-MS).     

Preparation of carrier-free group tracers from a gold target irradiated by high-energy heavy ions

A rapid radiochemical separation procedure has been finished by using of radiochemical separation and -spectrum measurement methods. In this isolation procedure, tantalum nuclides produced by the irradiation of natural tungsten targets with 14 MeV neutrons were extracted by methyl isobutyl ketone (MIBK) in the system of HF-HNO₃ mixed solutions. It has been found that tantalum was rapidly and efficiently separated in the isolation procedure and the decontamination factors of tungsten were more than 10⁴. The procedure is simultaneously used to separate tantalum from tungsten bombarded with intermediate energy (47 MeV/u)¹⁸O beams. The measured -spectra showed that tantalum can be separated from most elements produced in the nuclear reactions except for a few elements.