Methylene chloride, extraction

Thienylacetarnidocephalosporanic acid (7.0 g) was suspended in water (60 ml) and stirred with pyridine (7 ml) until the acid dissolved. The resulting solution (pH 5.9) was kept at 35°C for 3 days, then filtered and extracted with methylene chloride (4 x 60 ml). The methylene chloride extract was back-axtracted with a little water and the total aqueous solutions were then percolated through a column of Dowex 1x8 resin, (100 to 200 mesh, 150 g) in the acetate form at pH 4.3. The column was washed with water until the optical rotation of the eluate fell to zero and the eluate (500 ml) was freeze-dried. The residual white solid was dissolved in the minimum volume of methanol and after a few minutes the pyridine derivative crystallized this is the cephaloridine product. 

To a solution of 6.78 g of 6a-fluoro-9a-bromo-11 (3,17a,21-trihydroxy-16a-methyl-1,4-preg-nadiene-3,20-dione-21 -acetate in 175 ml of acetone was added 6.78 g of potassium acetate and the resulting suspension was heated under reflux for a period of 17 hours. The mixture was then concentrated to approximately 60 ml volume at reduced pressure on the steam bath, diluted with water and extracted with methylene chloride. The methylene chloride extracts were combined, washed with water, dried over anhydrous sodium sulfate and evaporated. 

The combined methylene chloride extracts were dried over anhydrous sodium sulfate and the solvent removed to give the crude 2-amino-5-chloro-2 -fluorobenzophenone which upon recrystallization from methanol formed yellow needles rnelting at 94° to 95°C. 

Derivatization Dissolve less than 1 mg of methyl or ethyl ester in 1 ml of freshly distilled pyrrolidine and 0.1 ml of acetic acid. Heat the mixture in a sealed or capped tube (able to withstand high temperatures) at 100° for 30 min. Cool the reaction mixture to room temperature and add 2 ml of methylene chloride. Wash the methylene chloride extract with dilute HC1, followed by ion exchange water. Dry the methylene chloride extract with anhydrous magnesium sulfate.1... 

An aqueous extract of P. hysterophorus (collected in Puerto Rico) was partitioned into methylene chloride at pH 7, pH 10 and pH 2. Bioassays of the methylene chloride soluble fractions, using the bean second internode bioassay (13), showed that the highest activity was concentrated in the methylene chloride extract at pH 7. Extensive chromatographic purification (flash chromatography, medium pressure LC, preparative TLC) monitored by bioassay led to the isolation of the four sesquiter-... 

SPME/GC/MS is an efficient technique to reveal the presence of resinic substances in archaeological samples. Indeed, volatile terpenes are still present in very old archaeological samples (4000 years old), particularly in the case of compact matrixes, and can be trapped by the SPME fibre. In comparison with methylene chloride extraction, SPME is very specific and allows the direct analysis of the volatile terpenes content in complex mixtures including oils, fats or waxes. For this reason, headspace SPME is the first method to use when analysing an archaeological sample it will either allow the identification of the resin or indicate further sample treatment in order to detect characteristic triterpenes. The method is not really nondestructive because it uses a little of the sample but the same sample can be used for several SPME extractions and then for other chemical treatments. 

The checkers found that the purification of the pseudopelletierine could be simplified, at least in those preparations in which commercial acetonedicarboxylic acid was used. Thus, the crude product obtained by evaporation to dryness of the methylene chloride extracts can be sublimed directly. Two sublimations give pseudopelletierine of m.p. 62-64°, in 58-62% yield, comparable to the product obtained after the more extended purification procedure described in the text. 

Nonvolatile memory (NVM), silicon-based semiconductors in, 22 257-258 Nonvolatile methylene chloride extract (NVMCE), 23 158... 

This system was studied by Schwartz. Toluene at 10 ppm, nitric oxide at 1 ppm, and nitrogen dioxide at 1.2 ppm were irradiated with ultraviolet lamps in a 17-m batch reactor for 270 min. Collected aerosols were successively extracted with methylene chloride and then methanol. The methylene chloride extract was fractionated into water-soluble and water-insoluble material, and the latter fraction was further divided into acidic, neutral, and basic fractions. The acidic and neutral fractions were analyzed by gas chromatography and chemical-ionization mass spectrometry the compounds identified are shown in Figure 3-7. The two analyzed fractions represented only about 5.5% of the total aerosol mass. It is noteworthy that classical nitration of an aromatic ring appears to... 

General procedure for the cyclization of f-(aryltelluro)propenoyl chlorides with aluminium chloride The propenoyl chloride derivatives were dissolved in methylene chloride (1 g, 10 mL) under a nitrogen atmosphere. The solution was cooled to -78°C, and 1.1 equiv of aluminium chloride was added. The cooling bath was removed and the reaction was allowed to warm to room temperature. After stirring for 1 h at room temperature, the reaction mixture was poured into ice-water, and the products were extracted with several portions of methylene chloride. The combined methylene chloride extracts were dried over sodium sulphate and concentrated. The residues were recrystallized from methanol if NMR spectroscopy showed a single product. 

The reaction mixture is diluted with an equal volume of water and ex"fcra,cted with a 400-ml. and a 200-ml. portion of methylene chl oride. The combined methylene chloride extracts are washed -with three 250-ml. portions of aqueous 20% sodium chlori e, dried over anhydrous magnesium sulfate, and concentrated to leave a yellow solid. Recrystallization from acetone gives 8.0-9.3 g. (55-64%) of crystalline a-diazo ketone, m.p. 200-202 dec. (Note 10). 

In sediment and soil samples, the isomers of cresol are determined by transferring a small portion of the solid sample (1 g) to a vial and adding methylene chloride. The contaminants are extracted from the sample with the aid of an ultrasonic probe. The methylene chloride extract is filtered, concentrated, and subjected to GC/MS analysis for quantitation. 

Antibacterial activity. Methylene chloride extract of the dried aerial parts of the plants, on agar plate at a concentration of 1 g/mL, was active on Bacillus subtilis L Methanol extract of the shade-dried plant, on agar plate at a concentration of 0.6 mg/mL, was inactive on Staphylococcus aureus. A concentration of 10 mg/mL was inactive on Escherichia coli and Pseudomonas aureugi-nosab L... 

Anticrustacean activity. Methylene chloride extracts of the dried leaf and root, at a concentration of 500 ppm, were inactive on Artemia salina. The assay system was intended to predict for antitumor activity. Methanol extract of the dried root, at a concentration of 500 ppm, was inactive on Artemia salina ° K Ethanol extract of the shade-dried seed was inactive on Artemia saliruf ° ... 

Cytotoxic activity. Ethanol (90%) extract of the dried entire plant, in cell culture at a concentration of 0.25 mg/mL, was active on human lymphocytes Veto cells, effective dose (EDljo 0.36 mg/mL Chinese hamster ovary cells, EDjo 0.44 mg/mL and Dalton s lyphoma, EBj LZ mg/mL . Methylene chloride extract of the dried leaf, in cell culture, produced weak activity on CA-colon-SW 480, inhibitory concentration (IO506.I p,g/mL. A concentration of 500 ppm was inactive on CA-human-colon-CO-115 . Methylene chloride extract of the dried root, in cell culture at a concentration of 500 ppm, was inactive on CA-human-co-lon-CO-115 and active on CA-colon-SW 480, IC50 3.6 p-g/mL. Methanol extract of the dried root, in cell culture at a concentration of 500 ppm, was inactive on CA-colon-SW 480 and CA-human-colon-CO-115 . Ethanol (50%) extract of the seed, in cell culture, was inactive on CA-9KB, ED50 greater than 20 pg/mL 5 Water extract of the dried seed, in cell culture at a concentration of 500.0 pg/mL, produced weak activity on CA-mammary-microal-veolar . Water extract of the dried seed, in cell culture at a concentration of 500 pg/ mL, was inactive on CA-JTC-26 . Seed oil, in cell culture at concentrations of 0.01% and 0.1%, was inactive on the rat fibroblasts. A concentration of 1% produced weak activity " " . Seed oil, in cell culture at... 

Four hundred milliliters from each specimen were put through an XAD-2 column and the adsorbed material was eluted. Methylene chloride extracts of the post-column urine eluate were made and tested for mutagenicity with the Salmonella/... 

The same statistical procedures were used here to evaluate the effects of humics on batch and continuous LLE. A base extraction procedure (19) was required for processing methylene chloride extracts prior to GC injection in order to protect the GC column from contamination by humics. This process led to losses of 2,4-dichlorophenol and the chlorinated biphenyls. Therefore, these compounds were not used in the evaluation of the CLLE in the presence of humics. All other compounds were not affected by the base extraction procedure. The ANOV procedure tested each compound for changes in concentration by comparing early batch extraction recoveries (from freshly prepared solution) to later ones (after the 12.5-L extraction). This process was done separately for Parts 1 and 2. It was therefore possible to test each compound for time-dependent decreasing concentration with and without the presence of humics. 

The partitioning of Fluka humic material was studied at pH 3 and pH 7 to ascertain the amount of potential interference with subsequent GC analysis (19). Water-methylene chloride partition coefficients were determined by quantification of the humic concentration in pH 3 and pH 7 salt solutions by UV analysis at 254 nm of the humic material before and after methylene chloride extraction. The method followed the procedure of Suffet and Faust (7) in which p-values (fraction recovered in methylene chloride at 1 1 water methylene chloride) and E-values (fraction recovered in methylene chloride at any specified water-to-solvent ratio) were calculated. Watenmethylene chloride (10 1) was used for all E-value calculations. The values obtained were as follows for pH 3, p-value = 0.48 and 10 1 E-value = 0.07 for pH 7, p-value = 0.19 and 10 1 E-value = 0.02. 

The second series of methylene chloride extractions was accomplished by the addition of 300 mL of solvent to the aqueous layer, homogenization for 1 min, then pH adjustment to <2 via the addition of 6.0 N hydrochloric acid. Following an additional homogenization for 1 min, the suspension was centrifuged and processed as for the base-neutral extractions. The extrac-... 

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