Solvent isolate

Before protein molecules attain their native folded state they may expose hydrophobic patches to the solvent. Isolated purified proteins will aggregate during folding even at relatively low protein concentrations. Inside cells, where there are high concentrations of many different proteins, aggregation could therefore occur during the folding process. This is prevented by... 

A mixture of4-(dodecylsulfanyl)phthalonitrile(9, R = SC,2H25 0.25 g, 0.76 mmol), anhyd NiCI2 (0.028 g, 0.22 mmol) and quinoline (0.4 mL) was heated and stirred at 200 C for 5h under argon. After cooling to rt, the mixture was treated with EtOH (5 mL), filtered, and washed successively with the same solvent. Isolation of the metal phthalocyanine was carried out using column chromatography (silica gel, hexane/ CH2C12 5 3) yield 0.067 g (26%). 

Through the extensive efforts of the past two decades, the C—H oxyfunctionaUzation of numerous organic compounds has been accomplished under quite mild reaction conditions, that is, at subambient temperature and in acetone solvent (isolated dioxirane) or in aqueous media (in-situ generation). Some of the typical examples are summarized in Scheme 13. 

To learn whether people from the ancient British coastal town of Barton-on-Humber ate mainly plants or fish, cholesterol from the bones of 50 people was extracted with organic solvent, isolated by gas chromatography, combusted to convert it into COz, and its 13C/I2C ratio measured by mass spectrometry. Observed 13C/12C ratios differ from that of a standard material by about —21 to —24 parts per thousand. A diet of local plants yields a 5I3C value (defined in Box 22-3) in cholesterol of —28 parts per thousand. Values more positive than —28 parts per thousand are indicative of a marine diet. It appears that the population got much of its food from the sea. 

Name amino acid amino acid amino acid formula MW mp [o]d Solvent Isolated from the plant Plant family Ref.o... 

If we then compared the solvents isolated after preheating at low and high severities we find that the solvent which has been subjected to higher severity is shifted to higher boiling point distribution by virtue of the loss of lighter boiling components. 

Several attempts were made to isolate the amine oxide as a hydrochloride salt. Usually the salt did not crystallize, but a hygroscopic oil resulted on evaporation of the solvent. Isolation was simplifled by using picric acid, for the picrates crystallized on standing. 

When the solvent-isolated losartan was subjected to DSC characterization, the DSC curve (Fig. 3-5, curve A) showed a minor endotherm at an extrapolation onset temperature of about 229°C (10°C/min) and a major melting endotherm at an extrapolation onset temperature of about 273°C (10°C/min). When a sample of Form I was heated to 255°C and then cooled back to room temperature, the subsequent DSC curve showed only the high-temperature endotherm (Fig. 3-5, curve B). Chemical analysis (HPLC) and solution NMR showed no change in the material heated to 255°C and cooled back to room temperature. However, XRPD indicated a change in the crystal structure. Therefore, it was concluded that the minor endotherm corresponded to a kinetically irreversible enantiotropic polymorphic transition and that the losartan system was not under complete thermodynamic control. Form I is the low-temperature stable form, up to the transition point, and the high-temperature stable form was... 

Periodic box The properties of a population of molecules is represented by the time-average behavior of a single molecule and its associated solvent isolated in a... 

Polar solvent Isolation of polar nonvolatile products may be problematic... 

C 4H,404, Mr 246.26, yellow cryst., mp. 270 "C (subl.), 317°C (decomp.), very poorly soluble in all organic solvents. Isolated from the yellow-orange rhizomorphs of the fungus Pitoderma croceum (=Corticium cro-ceum) that occurs on wood and in the acidic soil of conifer forests. 

Completed polymerizations can be terminated at -78°C by introducing a protic material such as methanol or acetic acid in which case the product will have isobutyrate ester termini. Alternatively the mixture can be warmed to room temperature whereupon spontaneous termination occurs to form cyclic ketone ends (2). With THF solvent, isolation of polymer is accomplished by precipitation in water, hexane or methanol depending upon the sorts of contaminants or by-products one wishes to remove or, the polymer solution can simply be stripped free of solvent. 

NaOH). The reaction mixture is usually allowed to reflux with good agitation for 23 to 30 hours in a solvent. Isolation of a pure product is followed by filtration and recrystallization techniques. The five different methods for the synthesis of cyclic polyethers are shown in the following equations where R represents aromatic groups, R represents either aromatic or aliphatic groups, and X represents halides. In addition, we will include an example for each method described in this section. 

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