Bases extractions

LiOH, DMF, HSCH2CO2H, 93-98% yield. This method has the advantage that the thioether by-products can be washed out by acid/base extraction. ... 

One gram of 6,7-dihydro-5H-dibenz[c,e] azepine hydrochloride was dissolved in water, made alkaline with concentrated ammonia, and the resultant base extracted twice with benzene. The benzene layers were combined, dried with anhydrous potassium carbonate, and mixed with 0.261 g of allyl bromide at 25°-30°C. The reaction solution became turbid within a few minutes and showed a considerable crystalline deposit after standing 3 A days. The mixture was warmed VA hours on the steam bath in a loosely-stoppered flask, then cooled and filtered. The filtrate was washed twice with water and the benzene layer evaporated at diminished pressure. The liquid residue was dissolved in alcohol, shaken with charcoal and filtered. Addition to the filtrate of 0.3 gram of 85% phosphoric acid in alcohol gave a clear solution which, when seeded and rubbed, yielded 6-allyl-6,7-dihydro-5H-dlbenz[c,e] azepine phosphate, MP about 211°-215°C with decomposition. 

A solution of 150 g (0J44 mol) of d(+)6-phenyl-2,3,5,6-tetrahydroimida2o[2,1-b] thiazole, d-10-camphorsulfonate in water is treated with 15.5 g (0.378 mol) of 98% sodium hydroxide and the liberated base extracted with chloroform. The chloroform solution Is washed with water followed by sodium chloride solution and dried over magnesium sulfate. Evaporation of the solvent left 72.1 g of residue which crystallized shortly. The free base hereby obtained has a melting point of 60°C to 61.5°C and an opticai rotation + 85.1 (C = 10, CHCI3). 

Malien-Aubert, C., Dangles, O., and Amiot, M.J., Color stability of commercial anthocyanin-based extracts in relation to phenolic composition protective effects by intra- and intermolecular copigmentation, J. Agric. Food Chem., 49, 170, 2001. 

The above-mentioned results indicate the additive effect of protons. Actually, a catalytic process is formed by protonation of the metal-oxygen bond instead of silylation. 2,6-Lutidine hydrochloride or 2,4,6-collidine hydrochloride serves as a proton source in the Cp2TiCl2-catalyzed pinacol coupling of aromatic aldehydes in the presence of Mn as the stoichiometric reduc-tant [30]. Considering the pKa values, pyridinium hydrochlorides are likely to be an appropriate proton source. Protonation of the titanium-bound oxygen atom permits regeneration of the active catalyst. High diastereoselectivity is attained by this fast protonation. Furthermore, pyridine derivatives can be recovered simply by acid-base extraction or distillation. 

Virnig, M. J. Mackenzie, J. M. W. Adamson, C. The use of guanidine-based extractants for the recovery of gold. Symposium Series—South African Institute of Mining and Metallurgy 1996, S16, 151-156. 

Bhaskara Sarma, P. V. R. Reddy, B. R. Liquid-liquid extraction of nickel at macro-level concentration from sulphate/chloride solutions using phosphoric acid based extractants. Miner. Eng. 2002, 15, 461-464. 

A technical challenge with this step is to achieve RNA extraction of uniform quality and efficiency for each fraction. This is because the amount of RNA in each sucrose gradient fraction varies considerably and the high concentration of sucrose in the bottom fractions interferes with phase separation in typical phenol-based extraction steps. To address these problems, we spike each fraction with an aliquot of a foreign (control) RNA, which can be used later to correct for differences in RNA recovery (and reverse transcription efficiency) between samples. We then remove sucrose from the samples by precipitation of total nucleic acid and protein with ethanol. To purify RNA, a standard Trizol (Invitrogen) extraction is performed as outlined later (also see product insert). 

Acid and base extractions from this material have been shown to form spontaneous structures in solution termed coercevates that could easily form the basis for protypical membranes (more of this in Chapter 9). Hydrocarbons with chain lengths C15-C30 (both straight and branched chains) and of course PAHs, predominantly pyrene and fluoranthrene, polar hydrocarbons such as aromatic ketones, alkyl and aryl ketones, nitrogen and sulphur heterocycles and most intriguingly purine and pyrimidine analogues have all been observed from this rich carbonaceous cocktail of compounds. Why ... 

An organic base. Extract with 10% HCl-water solution. The strong acid turns the base into a salt (This turning the whatever into a salt that dissolves in the water solution should be pretty familiar to you by now. Think about it.). Then the salt goes into the water layer. 

Due to the effect of plant roots and the natural or normal decomposition of soil minerals, some phosphate and other nutrients will become available [7] during the growing season and thus must be accounted for. The soluble and exchangeable phosphate (i.e., the immediately available phosphate) and that portion of the soil phosphate that will become available to plants during the growing season are determined by the Olson extractant. A typical base extraction of soil nutrients is given in Procedure 11.7 ... 

Example 1 Amine salts—It is first changed to the water-soluble free base, extracted with an appropriate organic solvent and treated with an excess volume of standard acid subsequently, the solvent was evaporated, and the remaining acid determined with a standard base. 

In biotechnology, many of the usual organic solvents will degrade a sensitive product, such as a protein this has led to the use of mild aqueous-based extractants, such as water-polyethyleneglycol-phosphate mixtures, which will partition and concentrate the product in one of the two aqueous layers which are formed. 

The use of supercritical fluids and aqueous-based extractants is discussed in Section 13.8... 

The usage of whole rock data has, however, its ambiguities. Estimates of original magmatic 8 0-values is best achieved through analysis of unaltered phenocrysts within rocks. Laser-based extraction methods on small amounts of separated mineral phases have documented subtle, but resolvable differences among different types of basaltic lavas (EUer et al. 1996, 2000 Dorendorf et al. 2000 Cooper et al. 2004 Bindeman et al. 2004, 2005, and others). 

Although the imidazolidinone catalysts used within these transformations are simple, cheap, readily accessible and in some cases recyclable using acid/base extraction, considerable efforts have been made to examine alternative methods to separate and recycle the catalyst with good success. Examination of the structure of imidazolidinone 22 shows two convenient points for the introduction of a polymer or fluorous support, R and R, both of which have been examined (Fig. 4). Curran has shown that identical reactivity, diastereoselectivity and enantioselectivity can be obtained using a fluorous tag (23) [53]. The catalyst can easily be recovered and recycled using F-SPE with excellent yield, purity and levels of activity. Polymer- (24) and silica-supported (25) imidazolidinones reported by Pihko [54] (R substitution)... 

Although petroleum basically consists of hydrocarbons, there are smaller amounts of other types of materials. For example, carboxylic acids occur to the extent of about 0.1-3%. These can be isolated quite easily by base extraction and the mixture is known as naphthenic acid, which can be used... 

Details of the extraction methods for ficine (4) and isoficine (5) were not given. Phyllospadine (6) was isolated from the flavonoid-containing n-butanol-soluble extract from dried plant material (4). The alkaloids from Vochysia and Buchenavia were isolated by conventional procedures, utilizing acid-base extraction and subsequent column or thin-layer chromatography using silica gel or alumina (5,6). 

Linkage isomerizations, osmium, 37 335-339 Linked cubane clusters, Fe—S proteins, biological implications, 38 55-56 Linked macrocyclic ring systems, 45 75 dinuclear systems, 45 89-95 triaza ring systems, 45 76-87 Li—N—Li linkages, 37 100-101 Lipoxygenase, inhibitors, 36 41 Liquid-liquid extraction of metal ions, 9 1-80 with acidic P-based extractants, 9 34-48 with acidic P-based extractants dinuclear, 9 47-48 mononuclear, 9 34-47 with amines and amine oxides, 9 49-56 complexes in, 9 68-71 countercurrent extraction method, 9 15-25... 

The GC trace obtained from injection of a 10% w/v solution of bupivacaine free base extracted from an injection gave the trace shown in Figure 11.21. It is apparent from comparison with a standard for dimethylaniline that there is < 0.1 % of the impurity present although a number of other peaks due to excipients or impurities can be seen in the GC trace. 

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