Organic residuals isolation

Bromocyclopentyl-(o-chlorophenyl)-ketone, BP 111° to 114°C (0.1 mm) is isolated in the usual manner. Since it is unstable, it must be used immediately. The bromoketone (29.0 g) is dissolved in 50 ml of liquid methylamine. After one hour, the excess liquid methylamine is allowed to evaporate. The organic residue is dissolved in pentane, and upon evaporation of the solvent, 1-hydroxycyclopentyl-(o-chlorophenyl)-ketone N-methylimine, MP 62°C, is isolated. 

S7 The above CS2 solution from which Si 2 and most of the Sg has been crystallized at —78 °C is used for the preparation of S7, Sis and 820- Stirring of this solution at - 78 °C after addition of some glass powder (or seed crystals of S7) for about 2 hours results in the precipitation of finely powdered sulfur which is isolated by removing the solution by means of an immersion filter frit. The residue is extracted three times with small amounts of toluene (leaving an organe residue) from which S7 crystallizes on cooling to —78 °C. On recrystallization from CS2 pure S7 is obtained in 0.7% yield m.p. 39 °C... 

A flask was charged with 4-bromo-iodobenzene (0.079 mol), 4-methoxy-2-methyl-phenyl boronic acid (0.087 mol), palladium acetate (0.004 mol), and triphenyl phosphine (0.008 mol) and then treated with 200 ml acetone and 250 ml 2M NaHCO i. The mixture was refluxed at 65°C for 18 hours and was then treated with water and diethyl ether and the organic layer isolated. This layer was washed with 40 ml saturated sodium chloride solution and water, dried over MgSC>4, filtered, and concentrated. The residue was purified by column chromatography using silica gel with CH2C12/ hexane, 1 1, and then recrystallized in / , 7 3, respectively, and 16.4 g of product isolated. 

In the liquid chromatographic methods, separation of nitrofurans is generally carried out on nonpolar reversed-phase columns, the preferred sorbent being octadecyl bonded silica (Tabic 29.5). Polar columns containing cyanopropyl-based sorbents (164, 165) have also been used for die isocratic separation of nitrofuran residues isolated from edible animal products. A literature survey shows that there exists a clear preference for acidic mobile phases containing acetonitrile as the organic modifier (Fig. 29.5.1). 

Isolation of Residue Organics from Waters via XAD Chromatography. Residue organics were isolated from the water samples via XAD chromatographic procedures developed in our laboratory. Drinking water and ground water samples were processed via the XAD procedure described in publications (3, 9, JO, 21, 22) and detailed in the Interim Protocol developed for the USEPA (5). Waste water samples were processed via a modification of the XAD procedure (4). 

High-Performance Concentration System for the Isolation of Organic Residues from Water Supplies... 

Inorganic cations, although probably isolated by ion exchange, should not be soluble in the dichloromethane extract of the aqueous eluents and should probably remain therein. The experiment with lead(II) nitrate, which yielded <0.2 of the spiked Pb ion, supported this expectation. Therefore, heavy metal toxicity to bioassay systems should not be a problem for testing organic residues. Conversely, when inclusion of inorganics in a test residue is desirable, other recovery techniques should be considered. 

New Methods for the Isolation of Mutagenic Components of Organic Residuals in Sludges... 

A solution of trifluoroacetoamidine (37.8 mmol) in 20 ml methyl alcohol was treated with 4-methoxyphenylhydrazine hydrochloride (27 mmol) followed by 3.77 ml triethylamine, then stirred 6 hours at ambient temperature, and concentrated. The residue was treated with 20 ml water and 50 ml EtOAc/THF, 9 1, and the organic layer isolated. The aqueous layer was re-extracted with 50 ml EtOAc/THF, 9 1, and combined extracts were washed with water and brine. The solution was then dried using MgS04, concentrated, and 108.2% yield residue isolated and used without further purification. 

The Step 1 product (105 mg) dissolved in 6 ml dry DMF was treated with 75% NaH (0.94 mmol), then stirred 5 minutes, and treated with 2-chloroethylpyrrolidine hydrochloride (0.60 mmol). The mixture stirred 2 hours at 50°C and was then partitioned between CHCl3/2-propyl alcohol/water, 10 1 1, and the organic phase isolated. The solution was washed twice with water, once with brine, dried with K2C03, then concentrated, and 130 mg of a light yellow solid isolated. The residue was dissolved in 8 ml methyl alcohol, then treated with ferric chloride hexahydrate (0.11 mmol), charcoal (5 mmol), and 1,1-dimethyl hydrazine (25 mmol), then refluxed 3 hours. 

The amide intermediate was dissolved in 10 xl CH2C12, then treated with acetyl chloride and 13 xl Af,Af-diisopropylethylamine. It was then partitioned between EtOAc and water and the organic layer isolated, then dried, and concentrated. The residue was then dissolved in water/dioxane, 1 1, followed by 10 mg K2C03 and then stirred 2 hours. The mixture was partitioned between EtOAc and the organic layer isolated. This organic layer was dried, triturated with diethyl ether, and 20 mg of product isolated. 

The Step 11 product (5.76 mmol) dissolved in 60 ml CH2C12 was treated with methanesulfonyl chloride (6.34 mmol) at 0°C followed by the dropwise addition of triethylamine (6.9 mmol) and then stirred for 30 minutes. It was then quenched with 1M HC1 and the organic layer isolated. The organic phase was washed with brine, dried, filtered through silica gel, and concentrated. The residue was recrystallized using EtOAc/ethyl alcohol, 1 1, and the product isolated in 95% yield as a white solid. 

A solution of 2,2-dimethyl-l,3-dioxane-4,6-dione (65 mmol) and pyridine (100 mmol) dissolved in CH2C12 at 0°C was treated with the dropwise addition of 3-methoxyphenylacetyl chloride (10.0 g) over 2 hours, then stirred an additional 2 hours at ambient temperature. The mixture was partitioned between 2 M HC1 and CH2C12, the organic layer isolated, dried, and concentrated. The residue was isolated as an oil and used without further purification. 

A mixture consisting of the Step 4 product (0.22 mmol) and 1 ml apiece trifluoroacetic anhydride and trifluoracetic acid were heated in a sealed tube for 10 hours at 45°C, then concentrated. The residue was partitioned between EtOAc and NaHC03 and the organic phase isolated. It was dried with Na2S04 and then reconcentrated. The residue was purified by chromatography using hexane/EtOAc, 3 1, and the product isolated in 35%yield as an yellow solid. 

A solution of the Step 7 product (0.054 mmol) and KOH (3.6 mmol) in 3.0 ml ethyl alcohol was heated to 90°C for 24 hours in a sealed tube, then partitioned between EtOAc and 1M HC1, and the organic phase isolated. It was washed with water, dried, and concentrated. The residue oil was purified by preparative HPLC and the product isolated in 31% yield as a solid. 

Bromine (9.62 g) dissolved in 30 ml chloroform was added to acetovanillone (10.0 g) dissolved in 150 ml chloroform at 0 to — 5 °C, the mixture stirred 4 hours, and the residue isolated. The residue was washed with water, the organic layer dried, concentrated, tritrated with diethyl ether, and the product isolated, mp = 148-152°C. 

The pre-electrolysis of 1 mmol of MesSiCl for about 1.5 h preceded the main electrolysis to eliminate formed fiom hydrolyses of the chlorosilane by residual water. The silanone precursor (50 mmol) and a trap (55 mmol) were then injected into the cell using a syringe, and the electrolysis was continued with constant flow of O2 through the solution (5 mL min ) and the current density j 5 - 7 mA cmT, the cathode potential not to exceed -2 V. From THF and DMF solutions, the products were isolated as described earlier [6, 7] when the process was carried out in IL, thorough extraction with diethyl ether, evaporation of the latter and distillation of the organic residue were effected to isolate the products. 

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