Sodium acetate Subject

The unsaturated amides (RCH=CHCONH2, where R = aryl or heteroaryl) in the presence of sodium acetate and NBS gave 3-bromoazetidin-2-ones 67 in moderate yield, probably by cyclization of 68 <99JCS(P1)2435>. The mesylate 69 cyclized in the presence of base to 70 and, after deprotection, the racemic P-lactam was subjected to lipase-mediated resolution to yield 71 (R = Et, ee 99%) and the amino acid 72 (R = Et, ee 98%) . 

Starting with the same acetal (35), but proceeding by way of the diacetate 40, instead of the dibenzoate 36, it was possible to prepare,51 in high yield, the p-toluenesulfonate 41 by sequential trityla-tion and p-toluenesulfonylation. Compound 41 was then subjected to solvolysis in the presence of sodium acetate in moist N,N-dimethyl-formamide, and the product (42) was successively acetylated and de-tritylated to give 3,4,6-tri-0-acetyl-2,5-anhydro-D-allitol (43). The... 

Xylanase II was subjected to cation exchange chromatography with a 20-mm i.d., 700-mm long CM-Trisacryl column eluted with 0.8 mL/min of 0.025M sodium acetate buffer at pH 4.5, with a 0-0.2M sodium chloride gradient. Only one protein peak eluted from the column it contained all the Xylanase n activity. This material appeared... 

Mild oxidation of o-nitrobenzaldehyde arylhydrazones with either bromine and sodium acetate or lead tetraacetate results in the overall loss of two hydrogen atoms and production of a class of iV-aryl heterocycles, tiie structure of which was the subject of uncertainty and some controversy for more than fifty years. These oxidation products were first prepared and investigated by Chattawayj " who described them as isodiazomethanes and formulated them as the triaziridine derivates 72. Structural assignment was based entirely on evidence from degradation studies in particular, Chattaway showed that reduction of... 

The syntheses described in this subsection rely upon the availability of o-diaroylbenzenes. A few methods seem to be of broader applicability. As Adams and co-workers have shown, the Diels-Alder reaction of dienes and diaroylethylenes gives 4,5-diaroylcyclohexenes, which on subsequent treatment with catalytic amounts of acid (sulfuric or phosphoric) form 4,7-dihydrobenzo[c]furans. Subjecting these compounds to the action of 2 moles of bromine in acetic acid in the presence of sodium acetate resulted in diaroylbenzenes (Eq. fi). - - ... 

A novel route to anthracyclinones is based on the chemistry of quinone-isobenzofuran adducts (77TL3537). The 3-methoxybenzyne-furan adduct (1) was reacted with a-pyrone to give a mixture of lactones (2). Thermolysis of this intermediate in the presence of quinone (3) gave in 93% yield the tetracyclic adduct (4) as a stereoisomeric mixture. Aromatization with sodium acetate in acetic acid gave quinone (5) which was subjected to reduction, C-ring oxidation and mild acid hydrolysis to afford a mixture of ( )-7-deoxydaunomycinone (6) and its 1-methoxy regioisomer (Scheme 1). 

The above outline is general, but is subject to variation for the particular amine under estimation. For instance, the amount of sodium carbonate—the essential point is to have the mixture alkaline during the coupling—depends on the acidity of the diazonium solution, and the presence of acid groups, such as sulphonic. When the coupling is carried out in acetic acid solution, sodium acetate is added in place of sodium carbonate and in three times the quantity. 

An interesting intramolecular cyclization takes place when 1,3-di-(2-pyridyl)-propane-l,3-diol is treated with sodium acetate in refluxing acetic acid.93 l-Acetyl-3-(2-pyridyl)indolizine is formed in 30% yield. Support for the proposed mechanism, shown in Scheme 14, is the observed increase in yield when the reaction is subjected to UV irradiation, which would be expected to increase the proportion of the ds-olefin present. 

The residue was subjected to azeotropic operation with toluene two times, and ether was added to the residue. The precipitate derived from trioxane was removed by filtration and washed with ether, and the combined ethereal solutions were concentrated under reduced pressure. The residue was dissolved in ethyl acetate, and the solution was washed with water and aqueous saturated solution of sodium chloride, was dried, and was concentrated to give 4 g of an oily material. The oily material was dissolved in 20 ml of methanol and to the solution was added 20 ml of aqueous 1 N solution of sodium hydroxide, and the mixture was stirred for 14 hours at room temperature. After removal of methanol under reduced pressure, water was added to the mixture, and this solution was acidified to pH 3 with aqueous 2 N hydrochloric acid. The mixture was extracted five times with ethyl acetate, and the ethyl acetate extract was dried and concentrated to give 3.5 g of crude crystals. After addition of ethanol to the crude crystals, the crude crystals were filtered. The filtrate was concentrated, and to the residue was added ethanol and ethyl acetate, and precipitate was collected by filtration. The combined amount of the crude crystals was 1.6 g. After the combined crude crystals were methylated with diazomethane, the reaction product was dissolved in 20 ml of ethyl acetate. To this solution was added 1.5 g of sodium acetate and 300 mg of 10% palladium-carbon, and the mixture was stirred for 2 hours under hydrogen. Then, the reaction product was filtered, and after addition of aqueous saturated solution of sodium hydrogen carbonate to the filtrate, the mixture was extracted two times with ethyl acetate. The extract was washed with an aqueous saturated solution of sodium chloride, dried, and concentrated to give 1.3 g of crude crystals. The crude crystals were recrystallized from ethyl acetate to yield 765 mg of the title compound (melting point 134-135°C, yield 43%). 

The authors used silver salts since gold salts catalyzed the reaction with R=H (giving oxazole 34, Scheme 5.16) but not with R=Me. Moreover, only traces of the desired furopyrrolidinone were formed with the use of a cationic gold species activated with silver additives. Therefore, silver traces were thought to be the active reagent. Indeed, on activation of compound 33 mediated by AgN03 in the presence of sodium acetate (Scheme 5.16), the enol moiety V can then accomplish a nucleophilic attack to produce the pyrrolidinone W and after protonolysis give compound X. Pyrrolidinone Y (the enol version of X) can, in turn, be subject to an oxidative cyclization to yield the furopyrrolidinone 35. Two equivalents of silver salts are needed for the activation step and the oxidative cyclization. 

Amongst the earliest experiments carried out with a view to the quantitative determination of the limits of inflammability of combustible gases were those of Davy with fire damp, wfliich is mainly methane, CH4. Owing to the importance of this gas m connection with gob fires and explosions in coal mines, several other workers have also investigated it. The value of the results, however, is restricted by the fact that firedamp, like most natural products, is subject to very considerable variation in composition.3 Even Davy recognised that it was not pure methane indeed, perfectly pure methane is not easy to prepare in quantity. The gas, as obtained from sodium acetate, may contain as much as 8 per cent, of hydrogen, as well as ethylene.4 No doubt this variation m composition is one contributory cause of the very varied results listed in the table on p. 93. 

The supernatant was subjected to fractional precipitation with ammonium sulfate (step 5) and then with acetone (step 6). PTTH was recovered in the precipitates with 35-55% acetone, while bombyxins were recovered with 55-75% acetone. The 35-55% acetone precipitates were subsequently purified through five steps of conventional chromatography gel filtration on Sephadex G-50 with 0.5M Tris-HCl (pH 8.5) (step 7), anion exchange on DEAE-Sepharose C1-6B with 0.2M sodium acetate (pH 5.2)(step 8), cation exchange on CM-Sepharose C1-6B 0.1-0.5M NaCl in 0.05M sodium acetate (pH 5.2) (step 9), Hydrophobic adsorption on Octyl-Sepharose C1-4B with 4M ammonium acetate, 0.2M ammonium acetate and 40% acetonitrile in 0.2M ammonium acetate (step 10) and gel filtration on Sephadex G-75 with O.OIM phosphate buffer containing 0.2M NaCl and 2% butanol (step 11). 

The 8-amino-acid is subjected to chloraeetylation and the 8-chlor-acetamido-acid treated with sodium acetate. The glycyl compound forms minute needles, soluble in nuneral acids and alk s. 

Before crystallization trials, the protein was subjected to gel filtration on Superdex-75 (Pharmacia) in 50 mM sodium/potassium phosphate buffer, pH 7.4, containing 1 mM EDTA, 50 mM 2-mercaptoethanol, 150 mM sodium chloride, 5% glycerol and 5% 2-propanol, as described previously (12). The statine-based inhibitor, LP-149 (Ac-Nal-Val-Sta-Glu-Nal-NH2 e Nal is naphtylalanine and Sta is statine) (Fig. 1), was prepared at Lilly Research Laboratories (K. Hui, unpublished results). Crystallization was carried out at 4 °C using the hanging-drop vapor diffusion method as follows 2.5 //I of the FIV PR(D30N) at 7 mg/ml complexed with LP-149 (1 4 molar ratio) in 50 mM imidazole-HCl pH 7.0 containing ImM EDTA and 1 mM dithiothreitol were mixed with an equal volume of 2 M ammonium sulfate, 0.1 M sodium acetate, pH 4.6 (Hampton Crystal Screen, solution 47). Crystals appeared within a few days and reached the size of 0.2 x 0.2 X 0.4 mm in one week. 

Fig. 19. UV chromatograms of the urine of normal subjects showing the effect of the diurnal cycle and the comparison between normal subjects. Run conditions column, 0.45 cm ID X 200 cm 316 stainless steel with 10-/t diameter Bio-Rad AG1-X8 urine samples, 2 ml each temperature, 25°C increasing to 60°C after 15 hours pressure, 1500-2300 psig elution, sodium acetate-acetic acid...

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