With acetonitrile

In step 1 of each oligonucleotide-synthesis cycle the 5 -terminal 4,4 -dimethoxytrityl protecting group is removed with trichloroacetic acid, and the support is washed with acetonitrile to prevent dctritylation of the next incoming phosphoramidite. The 4,4 -dimethoxy-... 

Pesticides. Chlorinated hydrocarbon pesticides (qv) are often found in feed or water consumed by cows (19,20) subsequently, they may appear in the milk, where they are not permitted. Tests for pesticides are seldom carried out in the dairy plant, but are most often done in regulatory or private specialized laboratories. Examining milk for insecticide residues involves extraction of fat, because the insecticide is contained in the fat, partitioning with acetonitrile, cleanup (FlorisH [26686-77-1] column) and concentration, saponification if necessary, and determination by means of paper, thin-layer, microcoulometric gas, or electron capture gas chromatography (see Trace and residue analysis). 

Nitroso compounds are formed selectively via the oxidation of a primary aromatic amine with Caro s acid [7722-86-3] (H2SO ) or Oxone (Du Pont trademark) monopersulfate compound (2KHSO KHSO K SO aniline black [13007-86-8] is obtained if the oxidation is carried out with salts of persulfiiric acid (31). Oxidation of aromatic amines to nitro compounds can be carried out with peroxytrifluoroacetic acid (32). Hydrogen peroxide with acetonitrile converts aniline in a methanol solution to azoxybenzene [495-48-7] (33), perborate in glacial acetic acid yields azobenzene [103-33-3] (34). 

Sugar analysis by hplc has advanced greatly as a result of the development of columns specifically designed for carbohydrate separation. These columns fall into several categories. (/) Aminopropyl-bonded siHca used in reverse-phase mode with acetonitrile—water as the eluent. (2) Ion-moderated cation-exchange resins using water as the eluent. Efficiency of these columns is enhanced at elevated temperature, ca 80—90°C. Calcium is the usual counterion for carbohydrate analysis, but lead, silver, hydrogen, sodium, and potassium are used to confer specific selectivities for mono-, di-, and... 

The reaction of calcium iodide and strontium iodide and the ion in tetrahydrofuran (THF) followed by treatment with acetonitrile... 

The esters of thiosulfinic acid R -SO,-S-R are used as fungicides and antibacterial prepai ations. These compounds have similar stiaicture fragments to allicin - natural insecticide from garlic with following structure (CH =CH-CH ),[SO-S] (http //www.ALLICIN.com). For deter-mination of ethyl S-ester of 4-aminobenzenthiosulfinic acid (esulan) in the ointment RP-HPLC was proposed [1] with acetonitrile water=30 70 as eluent. For seai ching bioactive compounds the synthesis of new esters of thiosulfinic acid is perspective that was confirmed by results of recent studies as instance [2]. Therefore requirements ai e existed for investigation HPLC sepai ations of these substances. 

We present here examples of this condensation with an aromatic aldehyde and a cyclic ketone. Both of these examples are useful because, although other methods are available for their preparation, problems often attend these syntheses. In the synthesis of cyclohexy11deneaceton1tr11e, for example, the standard method results exclusively In the g.y-lsomer and none of the a,g-Isomer. In Part A of this procedure, cyclohexanone Is condensed with acetonitrile to give predominantly the conjugated Isomer (80-83%) whicfi is then separated from the nonconjugated isomer by selective bromination. 

The method described is a modification of the procedure used by Ghosez to synthesize cinnamonitrile. 3-(2-Furyl)acrylo-nitrile has been prepared by catalytic condensation of furfural with acetonitrile in the vapor phase at 320°, by dehydration of the corresponding amide over phosphorus pentachloride, and by decarboxylation of 3-(2-furyl)-2-cyanoacrylic acid. ... 

The demand for isoprene for Butyl rubber led to the development of a recovery process for this Cj diolefin. Extractive distillation with acetone was the first process used but it has been replaced with acetonitrile (ACN ). The first step in the process is the fractionation of steam cracker debutanizer bottoms in a conventional two tower system to produce a C5 cut containing 30% isoprene. The first tower rejects C and heavier while the second rejects C4 and lighter materials. 

Since most of the C, hydrocarbons boil extremely close to isoprene, simple distillation of the C, cut would not produce high purity isoprene. Two stages of extractive distillation with acetonitrile are used where the ACN modifies the relative volatilities of the hydrocarbons and thus enables the separation to be made. 

This method can also be used to analyse soil samples. For instance, fenpropi-morph, which is a non-polar pesticide with good UV sensitivity but poor selectivity, has, after treatment, been determined in soil samples (31). In this example, an amount of soil was extracted overnight with acetonitrile this was then poured into a Buchner filter and rinsed with the same solvent. The acetonitrile solution was concentrated and, prior to LC analysis, the extract was diluted with water and 100 p.1 were then injected into the LC system. 

The product was filtered, washed with acetonitrile and dried in vacuo to yield 200 mg. 

This compound may be produced by reacting o-chlorobenzophenone with acetonitrile in the presence of sodium amide or another strongly basic condensing agent, to form the nitrile of /3-phenyl-/3-o-chlorophenyl-hydracrylic acid, which is then hydrogenated to yield Tphenyl-l-o-chlorophenyl-S-aminopropanol-l. The latter intermediate compound is subsequently dimethylated with an agent such as methyl sulfate to provide the desired end product l-o-chlorophenyl-Tphenyl-S-dimethylaminopropanol. 

High-pressure pumps operating at up to 6000 psi are required to force solvent through a tightly packed HPLC column, and electronic detectors are used to monitor the appearance of material eluting from the column. Alternatively, the column can be interfaced to a mass spectrometer to determine the mass spectrum of every substance as it elutes. Figure 12.18 shows the results of HPLC analysis of a mixture of 10 fat-soluble vitamins on 5 jam silica spheres with acetonitrile as solvent. 

Mixture of amines. A suitable mixture for analysis can be prepared by accurately weighing roughly equal amounts of aniline and ethanolamine. The determination is best carried out using a solution made from about 4 g of each amine diluted to 100 mL with acetonitrile in a graduated flask. 

Aziridines 180 (Scheme 3.65) react with acetonitrile and BF3 Et20, a Lewis catalyst, to give imidazolines 181 in 65-95% yield [98], Under the same reaction conditions, however, the C-3 phenyl-substituted aziridine 182 (Scheme 3.66) afforded oxazoline 183 in 59% yield [97]. 

Since the initially formed enol ester rearranges slowly to an imide,3 the yield depends on the rate at which the isoxazolium salt reacts, and that rate is increased by vigorous stirring. The reaction time for the activation step is approximately 8 minutes in nitromethane at 25° and approximately 1 hour in acetonitrile at 0°. In reactions performed with acetonitrile as the solvent, the checkers did not obtain complete solution. The reaction flask should be kept in a water bath to minimize heat transfer from the magnetic stirrer to the reaction mixture. 

The synthesis of RDX via the Triazine Process (Ref 13) involves the condensation of formaldehyde with acetonitrile followed by nitration ... 

Kinetic studies on the nitration of nitrobenzene by nitronium borofhioride in the polar solvents sulphuric acid, methane-sulphuric acid, and acetonitrile show the reaction to be first-order in both nitronium salt and aromatic110. With the first two solvents, the rate coefficients are similar for nitration by nitric acid and by the nitronium salts, indicating a common nitrating entity. With acetonitrile the rate coefficients are very much lower, consistent with a much lower concentration of free nitronium ions in this medium and thus with the nitronium salts existing as ion pairs in organic solvents (see Table 25). 

Treatment of bis(pyridine) complexes of molybdenum and tungsten, M(f/ -allyl)Cl(CO)2(py)2 (M = Mo, W) with equimolar amounts of lithium amidinates Li[RC(NPh)2] (R = H, Me) afforded amidinato complexes of the type M(r -allyl)[RC(NPh)2](CO)2(py) (M = Mo, W). Reactions of the latter with acetonitrile, PEts, and P(OMe)3 have been investigated Free amidines react with M(r -allyl)Cl(CO)2(NCMe)2 according to Scheme 124 to give the corresponding bis(amidine) complexes. ... 

Quantitative HPLC analysis was carried out on a Spectraphysics 8720 chromatography system, a rapid scan detector by Barspec on a Zorbax ODS column with acetonitrile water 75/25 as the eluent. 

Water, plant tissue Extract with acetonitrile filter if necessary HPLC/UV/EC No data (water) 50 pg/kg (plants) 95-99 Clark et al. 1985... 

Recently the use of the boron trifluoride catalysed reaction in the synthesis of the oxazolylindole fragment 25 of the natural product diazonamide A has been reported.<96SL609> Thus the BF3-mediated reaction of the indolyl diazoketoester with acetonitrile gave oxazole 25 with simultaneous removal of the Boc-protecting group (Scheme... 

Many of the early workers who studied the thermal decomposition reactions of diazocarbonyl compounds found that the addition of copper metal or copper salts allowed the reaction to be achieved at a lower temperature,<63AG(E)565, 64CB2628, 73JOU431> although no detailed study of this catalytic effect was undertaken. Alonso and Jano studied the copper-salt reaction of ethyl diazopyruvate 26 with acetonitrile and benzonitrile. The... 

Kitatani et al. found that tungsten(VI) chloride would catalyse the formation of a range of oxazoles from benzoyl(phenyl)diazomethane and nitriles (Scheme 17).<74TL1531, 77BCJ1647> The reaction with acetonitrile was studied with a range of other metal chlorides, but all proved less satisfactory than WCle. They attributed the catalytic nature of tungsten(Vl) chloride to both its Lewis acidity and the affinity of tungsten for carbenes. 

Fruits vegetables Homogenization of sample with acetonitrile and clean-up on Florisil column GC/ECD <1 ppm (mg/kg) 101.5B103.6 ( endosulfan) 100B102 ( endosulfan) 92.9 (endosulfan sulfate) Mitchell 1976... 

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