Synthesis by extraction

Sekiguchi et al. [46] have reported the recycling and re-use of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, [C2mim][OTf], after poly (pyrrole) synthesis by extraction of the unreacted monomer with chloroform. The ionic liquid was reused five times with little change in the growth CVs of the polymer. 

Stern, J. R. Role of cofactors in pyruvate oxidation and synthesis by extracts of Clostridium kluyveri. In Non-Heme Iron Proteins Role in Energy Conversion, A. San Pietro, ed., Antioch Press, Yellow Springs, Ohio, pp. 199—210 (1965). 

N. Tsumura, N. Ojima, K. Sato, M. Shiraishi, H. Shimizu, H. Nabeshima, S. Akazaki, K. Hori, and Y. Miyake, "Image-Based Skin Color and Texture Analysis/Synthesis by Extracting Hemoglobin and Melanin Information in the Skin," ACM Transactions on Graphics (TOG), Vol. 22, No. 3, pp. 770-779,2003. 

Two molecules of vitamin A are formed from one molecule of -carotene. Vitamin A crystallizes in pale yellow needles m.p. 64 C. It is optically inactive. It is unstable in solution when heated in air, but comparatively stable without aeration. Vitamin A is manufactured by extraction from fish-liver oils and by synthesis from / -ionone. The role of vitamin A in vision seems to be different from its systemic function. See also relincne and rhodopsin. 

Aroma. Chemicals. Specialty chemicals produced either by extraction from natural sources or by synthesis, such as vanillin [121 -33-5],... 

SASOL. SASOL, South Africa, has constmcted a plant to recover 50,000 tons each of 1-pentene and 1-hexene by extractive distillation from Fischer-Tropsch hydrocarbons produced from coal-based synthesis gas. The company is marketing both products primarily as comonomers for LLDPE and HDPE (see Olefin polymers). Although there is still no developed market for 1-pentene in the mid-1990s, the 1-hexene market is well estabhshed. The Fischer-Tropsch technology produces a geometric carbon-number distribution of various odd and even, linear, branched, and alpha and internal olefins however, with additional investment, other odd and even carbon numbers can also be recovered. The Fischer-Tropsch plants were originally constmcted to produce gasoline and other hydrocarbon fuels to fill the lack of petroleum resources in South Africa. 

A detailed procedure for the use of MCPBA recently appeared in Reagents for Organic Synthesis by Fieser and Fieser. The commercially available MCPBA (Aldrich) is 85% pure the contaminant, m-chlorobenzoic acid, can be removed by washing with a phosphate buffer of pH 7.5. The epoxidation is usually performed as follows a solution of 3 -acetoxy-5a-androst-16-ene (2.06 g, 6.53 mmoles) in 25 ml of chloroform (or methylene dichloride) is chilled to 0° in a flask fitted with a condenser and drierite tube and treated with a solution of commercial MCPBA (1.74 g, 20% excess) in 25 ml chloroform precooled to the same temperature. The mixture is stirred and allowed to warm to room temperature. After 23 hr (or until TLC shows reaction is complete) the solution is diluted with 100 ml chloroform and washed in sequence with 100 ml of 10% sodium sulfite or sodium iodide followed by sodium thiosulfate, 200 ml of 1 M sodium bicarbonate and 200 ml water. The chloroform extract is dried (MgS04) and evaporated in vacuo to a volume of ca. 10 ml. Addition of methanol (10 ml) followed by cooling of the mixture to —10° yields 0.8 gof 16a,17a-epoxide mp 109.5-110°. Additional product can be obtained by concentration of the mother liquor (total yield 80-90%). 

In the first publication describing the preparative use of an enzymatic reaction in ionic liquids, Erbeldinger et al. reported the use of the protease thermolysin for the synthesis of the dipeptide Z-aspartame (Entry 6) [34]. The reaction rates were comparable to those found in conventional organic solvents such as ethyl acetate. Additionally, the enzyme stability was increased in the ionic liquid. The ionic liquid was recycled several times after the removal of non-converted substrates by extraction with water and product precipitation. Recycling of the enzyme has not been reported. It should be noted, however, that according to the log P concept described in the previous section, ethyl acetate - with a value of 0.68 - may interfere with the pro-... 

Dichlorodibenzo-p-dioxin was prepared from isotopic potassium 2,4-dichlorophenate uniformly labeled with Ullman conditions gave a 20.5% yield. Small amounts of dichlorophenoxy chlorophenol were removed from the product by extraction with sodium hydroxide before purification by fractional sublimation and recrystallization from anisole. Chlorination of 2,7-dichlorodibenzo-p-dioxin in chloroform solution containing trace amounts of FeCls and 12 yielded a mixture of tri-, tetra-, and pentachloro substitution products. Purification by digestion in boiling chloroform, fractional sublimation, and recrystallization from anisole was effective in refining this product to 92% 2,3,7,8-tetrachloro isomer, which also contained 7% of the tri- and 1% of the penta-substituted dibenzo-p-dioxin. Mass spectroscopy was used exclusively to monitor the quality of the products during the synthesis. 

A wheat germ, cell-free, translation extract was fractionated into three concentrated parts using ammonium sulfate the 0 - 40 % saturated fraction, the 40 - 60 % saturated fraction, and the ribosome fraction. These fractions were tested for their ability to enhance the translational activity of the wheat germ, cell-free extract for dihydrofolate reductase. The fortified cell-free system supplemented with the 0 - 40 % ammonium sulfate fraction enhanced the efficiency of protein synthesis by 50 %. 

Synthesis of metal carbonyl clusters on oxide surfaces (followed by extraction into a solvent and workup) is occasionally a more convenient and efficient method for preparation of a metal carbonyl cluster than conventional solution chemistry. This synthetic strategy offers the green chemistry advantage of minimizing solvent use, as the reaction often occurs in the absence of solvent. 

The BCI3 catalysed synthesis of novel block co-polymers of PVC with isobutylene is thought to involve microcations formed by extraction of a chloride ion activated by the chemical introduction of some unsaturation (44) (equation 17). 

Figure 4.21 Multiphase membrane reactor synthesis of ibuprofen from ibuprofen methoxyethyl ester applying a multiphase membrane reactor in batch mode followed by extraction and distillation for downstream processing...

It has been previously shown that selective etching of carbides is an attractive technique for the synthesis of various carbon structures. Carbon produced by extraction of metals from carbides is called carbide-derived... 

Recent reports describe the use of various porous carbon materials for protein adsorption. For example, Hyeon and coworkers summarized the recent development of porous carbon materials in their review [163], where the successful use of mesoporous carbons as adsorbents for bulky pollutants, as electrodes for supercapacitors and fuel cells, and as hosts for protein immobilization are described. Gogotsi and coworkers synthesized novel mesoporous carbon materials using ternary MAX-phase carbides that can be optimized for efficient adsorption of large inflammatory proteins [164]. The synthesized carbons possess tunable pore size with a large volume of slit-shaped mesopores. They demonstrated that not only micropores (0.4—2 nm) but also mesopores (2-50 nm) can be tuned in a controlled way by extraction of metals from carbides, providing a mechanism for the optimization of adsorption systems for selective adsorption of a large variety of biomolecules. Furthermore, Vinu and coworkers have successfully developed the synthesis of... 

Some investigators described artifactual DNA sequence alterations after formalin fixation, when testing DNA samples extracted from FFPE tissues. Williams et al.46 reported that up to one mutation artifact per 500 bases was found in FFPE tissue. They also found that the chance of artificial mutations in FFPE tissue sample was inversely correlated with the number of cells used for DNA extraction that is, the fewer cells, the more the artifacts. However, they mentioned that these artifacts can be distinguished from true mutations by confirmational sequencing of independent amplification products, in essence comparing the product of different batches. Quach et al.47 documented that damaged bases can be found in DNA extracted from FFPE tissues, but are still readable after in vitro translesion synthesis by Taq DNA polymerase. They pointed out that appropriate caution should be exercised when analyzing small numbers of templates or cloned PCR products derived from FFPE tissue samples. 

In addition to chemical-based drugs, a range of pharmaceutical substances (e.g. hormones and blood products) are produced by/extracted from biological sources. Such products, some major examples of which are listed in Table 1.2, may thus be described as products of biotechnology. In some instances, categorizing pharmaceuticals as products of biotechnology or chemical synthesis becomes somewhat artificial. For example, certain semi-synthetic antibiotics are produced by chemical modification of natural antibiotics produced by fermentation technology. 

These circumstances became apparent to the authors when they attempted to study the formation of KDO 8-phosphate as catalyzed by purified bacterial extracts. These extracts did not catalyze the formation of KDO 8-phosphate from D-ribose 5-phosphate, but required D-arabinose 5-phosphate as the substrate Heath and Ghalambor29 showed that the KDO 8-phosphate synthetase reaction, observed in Pseudomonas extracts by Levin and Racker, is also catalyzed by extracts from Escherichia coli strains 0 111 B4 and J-5. Rick and Osborn136 showed that the KDO 8-phosphate synthetase from a Salmonella typhimurium mutant conditionally defective in cell-wall synthesis had a KM of 6 mM as compared to a KM of 170 pM for the enzyme from wild-type cells. 

Aminoethyl)piperidine (16) is a base and nucleophile employed for removal of fluorenylmethyl-based protectors during synthesis in solution. The adduct formed with the released moiety can be separated from the peptide ester by extraction into a pH 7.4 phosphate buffer (see Section 7.11). 

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