Salt substitute, sodium preparation

Ethyl o-nitrophenylpyruvate and o-nitrophenylpyruvic acid 14-21 have been prepared by condensation of o-nitrotoluene with diethyl oxalate in the presence of potassium ethoxide,4 14 sodium ethoxide,16-20 or sodium methoxide.21 Sodium ethoxide is less reactive, however, and cannot be substituted successfully for potassium ethoxide in the present procedure, as it gives a very poor yield and poor quality of precipitated sodium salt. With sodium ethoxide the reaction does not appear to go to completion even under the conditions of refluxing ethanol usually employed,16-21 which are considerably more severe than the room temperature conditions employed with potassium ethoxide in the present procedure. o-Nitrophenylpyruvic add has also been prepared by hydrochloric acid hydrolysis of o-nitro-a-acetamino-dnnamic azlactone.4... 

More recently, the chiral o-substituted diarylsulfonium ylides 128 were obtained from menthoxysulfonium salts 129 and sodium dimethylmalonate (59). The desired sulfonium salts 129 were prepared from the corresponding sulfides and menthol in the presence of t-butyl hypochlorite and used further without isolation. 

Reduction of quaternary pyridine salts with sodium amalgam afford the 1,2-dihydro whereas sodium hydrosulphite gives the 1,4-dihydro derivative, respectively362. From a preparative point of view, partial hydrogenation of quaternary pyridinium salts in alkaline media to give substituted 1-methyl-A2-piperideines is very important363,364. 

The cyclization of O-allyl oximes 1, performed with diphenyl diselenide/ammonium thiosulfate/ trifluorosulfonic acid or phenylselenenyl bromide, gave cyclic iminium salts 2 via an intramolecular antt -addition mechanism. By addition of water to the reaction mixture, 3-substi-tuted isoxazolidines 3 are formed in good yield. When the salts 2 were prepared by using phenylselenenyl bromide, A-alkyl 3-substituted isoxazolidines 4 were afforded in good yield by reduction of 2 with sodium borohydride in methanol247-249. 

The reduction of diazonium salts by sodium sulfite forms monosub-stituted arylhydrazines. An improved procedure for the synthesis of phenylhydrazine in 84% yield is typical. Arylhydrazine salts substituted in the nucleus with halo," ether, carboxyl, or nitro groups have been prepared. The free bases are liberated from the salts by the action of aqueous sodium hydroxide or sodium acetate. 

Dialkylamino-substituted 1,2-diselenolylium cations have been prepared from 1,3-bis(dialkylamino)-l,3-dichloropropenylium chloride by treatment with sodium hydrogen selenide and subsequent oxidation with hydrogen peroxide or w-chloroperbenzoic acid <87BCJ2686>. These salts were also prepared by reaction with sodium diselenide in ethanol <86MCLC333>. 

Many achiral or chiral substituted and bridged 1,4-dihydropyridines have been prepared by a reduction of quaternary pyridium salts with sodium hydrosulphite as NADH models for enantioselective reduction of some prochiral substrates. A lithium aluminium hydride reduction of Af-acylenamines has also been observed " . 

Amino-l,3,5-triazine-2,4-dithiol (dithioammelide, 10) and its salts have been prepared from the cyano-substituted dipotassium imidodithiocarbonate 9 by reaction with sodium hydroxide solution,450 or by heating the salt in refluxing methanol,451 and subsequent acidification. 

All of the coumarin derivatives (Fig. 31.5) are water-insoluble lactones. Structure-activity relationship requirements typically are based on substitution of the lactone ring, specifically in positions 3 and 4. Although coumarin is a neutral compound, the clinically available derivatives are weakly acidic because of the presence of a 4-hydroxy substitution. The acidity of the proton on the 4-hydroxy group allows formation of water-soluble sodium salts for commercial preparations. Furthermore, warfarin (and, possibly, ... 

In many emulsion polymerization procedures, the original authors call for the use of ammonium persulfate as the water-soluble initiator. The shelf-life of this salt is quite limited and the concentration of available persulfate ions is quite variable from experiment to experiment. We therefore suggest, on the basis of our own experience, that either potassium persulfate or sodium persulfate be substituted for the initiation process, on a molar equivalent basis. Of these two latter salts, the sodium salt dissolves rapidly in water and usually may be added directly to the reaction flask. The potassium salt exhibits surprisingly low water-solubility. As a result, if potassium persulfate needs to be used, an aqueous solution of it should be prepared separately. Then this initiator solution is added to the emulsion polymerization system. 

The 6-0-benzyl protected dienes 4a and 4P were prepared from the known (10) 1,2-O-isopropylidene-a-D-glucofuranose (Scheme 3). In fhis case, evidence for the intermediate formation of aldehyde 23a in the Wittig reaction conducted at room temperature was obtained by comparison with an authentic sample of aldehyde 23a obtained directly from compound 21 (a + P) using P-tosyloxy acrolein prepaid in situ from the sodium salt of malonaldehyde and tosyl chloride in THF. Finally, the methyl substituted derivatives 5a and SP were prepared as for the parent dienes 2a and 2p according to Scheme 1 using the corresponding 2-methyl substituted sodium salt of malonaldehyde (72). 

Preparation of phosphonic acids Asymmetric substitution sodium salt Overall retention Overall retention... 

Cottam, H.B., Kazimierczuk, Z., Geary, S McKernan, P.A., Revankar, G.R., and Robins, R.K. (1985) Synthesis and biological activity of certain substituted deoxytuberddins prepared via stereospecific sodium salt glycosylation procedure. J. Med. Chem., 28,1461-1467. 

SNG Substitute natural gas. soaps Sodium and potassium salts of fatty acids, particularly stearic, palmitic and oleic acids. Animal and vegetable oils and fats, from which soaps are prepared, consist essentially of the glyceryl esters of these acids. In soap manufacture the oil or fat is heated with dilute NaOH (less frequently KOH) solution in large vats. When hydrolysis is complete the soap is salted out , or precipitated from solution by addition of NaCl. The soap is then treated, as required, with perfumes, etc. and made into tablets. 

The Sandmeyer reaction may also be applied to the preparation of nitriles. The solution of the diazonium salt is added to a solution of cuprous cyanide in excess of sodium or potassium cyanide solution (sometimes improved yields are obtained by substituting nickel cyanide for cuprous cyanide), for example CH3 CH, CH3... 

Carboxymethylcellulose Sodium. Carboxymethyl ether of cellulose sodium salt (Citmcel) (8) is a white granular substance soluble in water depending on the degree of substitution. It is equally soluble in cold and hot water and may be prepared by treating alkaU cellulose with sodium chloroacetate. 

Hydrazinium salts, N2H5 X, are acids in anhydrous hydrazine, metallic hydrazides, N2H, are bases. Neutralization in this solvent system involves the hydrazinium and hydrazide ions and is the reverse of equation 7. Metal hydrazides, formally analogous to the metal amides, are prepared from anhydrous hydrazine and the metals as well as from metal amides, alkyls, or hydrides. (The term hydrazide is also used for organic compounds where the carboxyUc acid OH is substituted with a N2H2.) Sodium hydrazide [13598-47-5] is made from sodium or, more safely, from sodium amide (14) ... 

Plutonium Purification. The aqueous feed for the second plutonium cycle is typically prepared by adding HNO and an excess of sodium nitrite, NaN02, to destroy the excess reductant and oxidize the Pu to the more extractable Pu . An alternative approach which reduces the amount of salt in the Hquid waste involves absorbing nitrogen tetroxide, N2O4, as a substitute for the NaN02 ... 

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