Dichloromethane-hexane

A-Fluoro-2,4,6-tnmethylpyndmium inflate (1 mmol) is added m several portions at room temperature to a tetrahydrofuran solution of sodium diethyl phenyl-malonate, obtained from 1 mmol of diethyl phenyl malonate and sodium hydnde at 0 C in tetrahydrofuran The reaction imxture is poured mto dilute hydrochlonc acid and extracted with ether The ether extract is washed with sodium bicarbonate and water and dned over magnesium sulfate The oily residue obtamed after removal of tihe ether is chromatographed on sihca gel (dichloromethane-hexane, 1 1) to give diethyl fluorophenylmalonate in 83% yield... 

The GC-MS data of fraction 1 revealed a strong peak of verticilla-4(20),7,ll-triene (compound 1) accompanied by small amounts of cembrane A and cembrane C. To purify the violet spot and isolate compound 1, it was necessary to reduce the solvent strength. In the mobile phase dichloromethane-hexane (9 + 1 v/v), the development time decreases, which leads to minor diffusion of the zone. The zone of (compound 1) was marked by X = 254 nm UV light. To exclude the impurities, the separation process had to be repeated several times. The zone was removed from the glass plate and eluted from die adsorbent with dichloromethane. The concentrated solution achieved was applied onto a TLC plate as well as injected onto a GC column the... 

Experimental Preparation of 5, 6-dinitrospirobenzothiopyran 44b. A mixture of 5-nitro-l,3,3-trimethyl-2-methyleneindoline (0.38 g, 1.75 mmol) and 5-nitro-thiosalicylaldehyde (0.22 g, 1.2 mmol) in EtOH (50 ml) was refluxed for 2h, and then evaporated under reduced pressure. The residue was chromatographed on silica gel with benzene-acetone (15 1, v/v) and recrystallized from dichloromethane-hexane to give 44b (R1 = N02, R2 = 6-N02)(0.30 g, yield 65%). 

With the long alkyl chain substitutions on the A-heterocyclic carbenes, lamella-structured silver(i) carbene complexes 27a and 27b (Figure 14) were isolated.74 It is interesting to note that the synthetic procedures for the two complexes are the same except for the use of different solvents of crystallization. The dinuclear 27a was obtained from recrystallization in dichloromethane- -hexane while the tetranuclear 27b was obtained from acetone. The structure of 27a could be interpreted as the dimeric form of [Ag(carbene)Br] bridged by intermolecular Ag-Br interactions. The Ag-G bond has a distance of 2.094(5) A. The tetranuclear 27b, on the other hand, could be regarded as two monocationic bis(carbene)silver(i) bridged by an [Ag2Br4]2 anion, with the presence of short Ag(cationic)-Ag(anionic) contact (3.0038(18) A) and comparable Ag-G bond distances (2.0945(5), 2.138(13) A). A related... 

The reaction of 1 with the boron trihalides BC13 and BBr3 turned out to be even more complex. At least three different types of compounds were formed, and the product ratio depended on the polarity of the solvent.30 In the reaction with BBr3 in dichloromethane/hexane (2 1), the boron compound 50 (X = Br) was isolated as the main product (Scheme 12) X-ray crystal structure analysis revealed the presence of a novel arachno-type cluster possessing a BC4 framework (Fig. 8). 

Water Extracted with dichloromethane/hexane, dry with sodium sulfate, concentrated. GC/ECD 0.05 ppb No data ASTM 1988... 

Waste water Extract sample with dichloromethane/hexane at pH 2, 7, and 10 elute from Florisil or alumina with ether/hexane GC/ECD 0.1 ng/injection >90 EPA 1981... 

The solvent and excess pentacarbonyliron are removed under reduced pressure and the product is recrystallized from dichloromethane-hexane. Yield 3.56 g (83% based on consumed pentacarbonyliron). 

The second bright yellow band separates from the third yellow band with 15% benzene-hexane. Removing the solvent and recrystallizing the residue from dichloromethane-hexane yields the secondary metallation products 2 (0.08g, O.lOmmol) and 3 (0.12g, 0.14mmol), respectively. These are the phosphine-substituted derivatives of the secondary metallation product described below. The yield of these two products may be maximized by heating the starting complex in the absence of solvent to 145 °C (whereupon it melts) for 15 to 20 min. 

Products are eluted with benzene-hexane mixtures. The compounds Mn2(CO)10 and Mn(CO)5CH3 precede the bright yellow product band. Removal of solvent and recrystallization from dichloromethane-hexane gives yellow crystals of 5 (0.32 g, 0.51 mmol). 

The solution is evaporated to dryness under reduced pressure and the residue is purified by thin layer chromatography (PF-254G silica gel with 1 4 dichloromethane-hexane eluant). Three yellow bands are eluted. The second band is removed and product extracted from it is recrystallized from hexane. Yield 0.12-0.15 g (30-33%) of the desired product. Checkers used column chromatography (35 x 3-cm column, Silica Gel 60, 70-230mesh, Merck) to give the product as the second band when eluting with 1 4 dichloromethane-hexane. 

Extract by column chromatography using hexane/dichloromethane/ hexane clean up using GPC Extract with n-hexane clean up using multi-layer column... 

For tissue analysis, the sample is extracted with ethyl acetate in the presence of sodium chloride and piperonyl butoxide. After centrifugation, the supernatant is evaporated to dryness, and the residue is dissolved with dichloromethane/ hexane (1 1) to be applied onto a Bond-Elut silica cartridge. Following successive cartridge washing with petroleum ether and ethyl acetate/hexane (4 6), chloramphenicol is eluted with ethyl acetate/hexane (7 3) and the eluate is evaporated to dryness. The residue is dissolved in 0.05 M Tris/hydrochloric acid buffer pH 10.4, extracted with diethyl ether, and the extract is evaporated to dryness. Tlie... 

Sample extraction and deproteinization is usually accomplished with nonpolar organic solvents at a specified pH. Organic solvents such as chloroform for the determination of cortisol in milk (529) dichloromethane/hexane (4 1) for the determination of free cortisol and its 21-acetate in milk (530) ethyl acetate for the determination of prednisolone, fluoroprednisolone, triamcinolone, and betamethasone in animal tissues (531) methylprednisolone in milk (532) fluoro-prednisolone in milk (533) and dexamethasone in milk (534) ethyl acetate in... 

Solid-phase extraction for milk, urine, and feces samples is carried out by washing the loaded Cig cartridge successively with 5 ml water, 5 ml acetone/ water (20 80), 5 ml methanol/water (20 80), 5 ml dichloromethane/hexane (20 80), and 5 ml ethyl acetate/hexane (10 90). The corticosteroids are eluted with 3 ml ethyl acetate. The eluate is evaporated, and the residual is reconstituted in 0.5 ml ethanol and 5 ml phosphate-buffered saline, pending subsequent immunoaffinity column cleanup. The solid-phase extraction procedure differs for liver samples. In that case, washing of the cartridge is performed with 5 ml water, 5... 

Cesium fluoroxysulfate in acetonitrile medium at 35 C converts primary alcohols and alkyl and aryl aldehydes into acid fluorides in high yields.i" Hammett correlation analysis of the fluorination of various benzene-substituted aldehydes gives the reactivity constant31 q = —0.38. It has been shown that solvent polarity plays an extremely important role in the conversion of aldehydes into fluorides the conversion is almost quantitative in acetonitrile, but completely stopped in dichloromethane, hexane or tetrahydrofuran. The presence of ni-... 

In a 25-mL, round-bottomed flask, bpy (0.065 g, 0.42 mmol) is added to a solution of PdClMe(tmeda) (O.llg, 0.40 mmol) in dichloromethane (10 mL). After stirring for 45 min hexane (2 mL) is added. The last step is repeated three times and during this period a yellow precipitate is formed. The solvent is evaporated in vacuo and the resulting solid washed with hexane (2 x 10 mL) and dried in vacuo. The product is a mixture of starting material and the desired complex. To ensure complete conversion, the entire procedure is repeated four times, after which the pure, pale yellow product can be obtained by repeated recrystallization from dichloromethane/hexane (0.08g, 63%). HNMR in CDC13 8 9.17 (d, 1H), 8.65 (d,lH), 7.91-8.12 (m, 4H), 7.52 (m,2H) [bpy], 1.00 (s, 3H) [PdMe]. 

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