Purification yield

Aldeen et al. (59) described 12,000-14,000 dalton extracts from Tealia felina that had hemolytic actions. Further purification yielded a protein of 7,800 daltons (60). 

Step Protein Total activity Specific activity Purification Yield... 

The thallous derivative so formed was found to undergo metathesis with methyl iodide and to yield thallous iodide and methyl cellulose. Analyses of the latter product for methoxyl content after suitable purification yielded a measure of the accessible hydroxyl groups. The reactions were all conducted in non-aqueous systems. 

Due to the strong and selective binding that characterizes many affinity ligands, solutes that are analyzed or purified with these ligands can often be separated with little or no interferences from other sample components. In many cases, the solute of interest can be isolated in only one or two steps, with purification yields of hundred- to several thousandfold being common [2,4-6]. In work with hormone receptors, purification yields approaching one millionfold have even been reported with affinity-based separations [5]. 

The octapeptide 27 (419 mg, 0.3 mmol) was hydrogenated over Pd/C in DMF (300 mL). The catalyst was removed by filtration, the filtrate concentrated, diluted with H20 (27mL), and extracted with Et20. The aqueous soln was passed through an ion-exchange column and the oxytocin analogue was obtained upon chromatographic purification yield 62 mg (83%) [a]D22 -98.4 (c 0.46, H20). 

Purification yields 200-300 mg of triphenylphosphine-stabilized gold nanoparticles, which should be stored cold (—20°C) in the sofid state, or immediately converted to thiol- or amine-stabilized nanoparticles through subsequent reaction with the appropriate ligand. The particles decompose in solution thus manipulation of the product in solution should be minimized. 

Boc-m-Ampa-OEt (55 3.60 g, 12.3 mmol) was dissolved in dioxane/H20 (3 1, 60 mL), which was brought to pH -10 with 2 M NaOH. After 4h at rt (the reaction was followed by TLC), dioxane was removed, the aqueous layer was extracted with CHC13 and then acidified with 10% citric acid, followed by extraction with Et20. After drying (MgS04) and concentration, the acid 56 was obtained as an amorphous solid which was used without further purification yield 3.12g (96%). 

To a well-stirred soln of trichloroacetyl chloride (1 kg, 5.5 mol) in Et20 (1.5 L) in a 12-L flask was added dropwise over a period of 3h a soln of 1-methylpyrrole (1 0.45kg, 5.5mol) in anhyd Et20 (1.5L). The soln was stirred for an additional 3 h, and the mixture was quenched by the dropwise addition of a soln of K2C03 (400 g) in H20 (1.5 L). The layers were separated, and the ether layer was concentrated under reduced pressure to provide 2 as a yellow crystalline solid sufficiently pure to be used without further purification yield 1.2 kg (-96%). 

A stirred suspension of Z-Alap (5.2 g, 20 mmol) and HC(OEt)3 (25 g, 170 mmol) was slowly heated. The ethyl formate and EtOH byproducts were continuously removed by distillation while allowing the temperature to rise to 135 °C where it was held for 1 h. The cooled mixture was filtered. The excess HC(OEt)3 was removed from the filtrate under a high vacuum leaving Z-Alap(OEt)2 as a viscous gum used in the next step without purification yield 6g (95%). 

To this material (52 mg, 49 pmol) was added pentafluorophenol (24 mg, 0.13 mmol) in EtOAc (lmL). The soln was cooled, and DCC (13 mg, 64 pmol) was added. This was stirred for 2h at 0°C and for 22 h at rt. This was filtered through Celite, concentrated, and passed through a plug of dry silica gel (EtOAc/iPrOH 10 1) to give the active ester, which was used without purification yield 50 mg (83%). 

The formation of a-naphthols of type 189 from 1-alkyl-substituted salts 30, on heating with dimethylamine hydrochloride in ethanol, occurs by another mechanism and will be explained in Section III,C,4,b,i. The interaction of l-aryl-3-carboxy-substituted salts 62 with secondary amines in benzene is initiated probably as in the reaction of these salts with primary amines, and the attack by the secondary amine on position 3 is the primary step of this reaction. However, since protonation of the intermediate anion 190, a masked acyl anion, becomes difficult, an interaction of this anion with the carbonyl group of the benzophenone fragment occurs (86KGS125). The enamines 191 thus formed are usually hydrolyzed on purification, yielding five-membered cyclic acyloins 192. 

Fluoro-FMMT, 294, 6-fluoro-FMMT, 295, and 2,6-difluoro-FMMT, 296, labelled with 18F, have been obtained316 in the direct reaction317 of 297 with Ac018F38 (equation 164). The specific activity at the end of 60 min preparation time was about 200 mCi/mmol. The HPLC purification yields a radiotracer which can be directly injected after sterilization for the assessment of presynaptic CNS dopamine nerve terminals using PET319. 

Adduct [Thiosalicylidene-N-(benzthiazolyl-2) Jpyridinatonickel(II) 734 (3.182) Obtained by heating the equimolar quantities of /u.v(thiosalicylaldehydato)nickel(II) and 2-benzthiazolylhydrazine in pyridine without additional purification. Yield... 

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