Dimethylsulfoxide, sodium salt

Dimethylsulfoxide, sodium salt, 50,62 Dimethylthiocarbamyl chloride, synthesis of, 51,140... 

The NMR spectrum shown in Figure 5 was obtained by dissolving hydralazine hydrochloride in deuterium oxide containing 3-(trimethylsilyl)-1-propane-sulfonic acid sodium salt (DSS). The series of peaks at 0, 0.6, 1.8, and 3 ppm are all due to the DSS. The peak at 4.8 ppm is due to HDO which forms on exchange with the solvent and the peaks at 8.01 and 8.61 ppm are due to the aromatic protons. The NMR spectrum of the base (Figure 6) was obtained in a 1 1 mixture of dimethylsulfoxide-d,- deuterochloroform. 

To a solution of 40 g (1.0 moles) of sodium hydroxide in 500 ml of methanol was added 242 g (l.Omoles) of 2.6-dichloro-4-bromophenol. The pH was adjusted between 9.0 and 10.0 (preferably 9.5) by means of one or another of the reactants. The pH was determined by diluting a 2.5 g aliquot with 100 ml of 50% aqueous methanol. The alcohol and water were removed by distillation, fn a one liter round bottom flask there was introduced 100 g of the sodium salt of 2.6-dichloro-4-bromophenol, 350 ml of chlorobenzene and 40 ml of N,N-dimethylformamide. The mixture was agitated until the salt was in solution then immediately there was added 26 ml of dimethylsulfoxide. A suspension forms. The air was removed by alternate evacuation and introduction of nitrogen then there was added 1.0 g of benzoyl peroxide dissolved in 10 ml of toluene. The mixture was stirred for 80 min at 29—33° C then for 5 hours at 54—59° C. The formation of polymer was indicated by the disappearance of the particles of the suspension and an increase in the viscosity of the solution. The polymer was isolated by precipitation into acetone. After filtration the polymer was washed thoroughly with water, then with acetone and then dried at 100° C. There was obtained 60 g (theoretical) of poly-(2.6-dichloro-1.4-phenylene ether). 

The yields of reaction products from thermal nucleophilic substitution reactions in dimethylsulfoxide of 0- and p - n itrohalobenzenes with the sodium salt of ethyl a-cyanoac-etate were found to be markedly diminished from the addition of small amounts of strong electron acceptors (nitrobenzenes). At the same time, little or no diminution effects on the yields of the reaction products were observed from the addition of radical traps such as ni-troxyls. These results are consistent with the conclusion that such reactions proceed via a nonchain radical nucleophilic substitution mechanism (Zhang et al. 1993) (Scheme 4-20). 

The synthesis of 18F-FET is carried out in two steps (Wester et al, 1999) First, ethylene glycol-1,2-ditosylate in acetonitrile is reacted with dry 18F-containing Kryptofix 2.2.2 and potassium bicarbonate at 90°C for 10 min. The product is purified by absorbing it on a polystyrene cartridge and then eluting with dimethylsulfoxide. Second, the eluate is mixed with dipotassium sodium salt of L-tyrosine and heated at 90°C for 10min. The mixture is purified by HPLC and cation exchange to afford 18F-FET. The radiochemical yield is about 40-45% with purity between 97 and 99%. 

Of the various methods of preparing phosphorus ylides, that much preferred — apart from a few exceptions — is the action of bases on phosphonium salts. The strength of the base is adjusted to the acidity of the phosphonium salt bases used have been carbon bases such as butyl- and phenyllithium, nitrogen bases such as sodamide, lithium diethylamide, and 1,5-diazabicyclo-[4.3.0]non-5-ene, and oxygen bases such as sodium hydroxide and potassium alkoxides. The pairs dimethylsulfoxide-sodium hydride1000 and dimethyl sulfoxide-potassium terf-butoxide1001 have proved particularly valuable. 

Initially, only dipolar aprotic solvents such as tertiary amines, acetonitrile (MeCN), di-methylformamide (DMF), V-methylpyrrolidinone (NMP), and dimethylsulfoxide (DMSO), were common. However, as originally observed by Heck, the presence of water can accelerate certain coupling reactions, "" and consequently the development has gone to water-soluble triarylphosphane ligands (e.g., tiiphenylphosphane m-trisulfonate sodium salt (TPPTS) ) with which many alkene arylations superbly succeed in aqueous solvent mixtures. ° ... 

Diphasic liquid systems used in CCC may have a wide variety of polarities. The most polar systems are the ATPS made by two aqueous-liquid phases, one containing a polymer, for example, polyethylene glycol (PEG), the other one being a salt solution, for example, sodium hydrogen phosphate. The less polar systems do not contain water there can be two-solvent systems, such as heptane/acetonitrile or dimethylsulfoxide/hexane systems or mixtures of three or more solvents. Intermediate polarity systems are countless since any proportion of three or more solvents can be mixed. Ternary phase diagrams are used when three solvents are mixed together. 

In the case of PSF, the aromatic nucleophilic displacement route involves a two-step process. In the first step, bisphenol A is converted to its dialkali salt analog by reacting bisphenol A with sodium hydroxide in a 1 2 stoichiometric ratio using dimethylsulfoxide (DMSO) as the reaction medium. A small amount of chlorobenzene is used in this step as part of the solvent system to distill off the water from the reaction medium, thereby maintaining anhydrous conditions. 

A new acid catalyst of potential use in the Bischler-Napieralski cyclization is P2O5 in methanesulfonic acid. The phenethylamines used in isoquinoline syntheses are usually prepared from the reduction of the corresponding /S-nitrostyrenes. A more versatile procedure starts with a substituted benzyl chloride which is converted to the nitrile using sodium cyanide in DMSO (dimethylsulfoxide). Reduction of the nitrile with LiAlH4 in the presence of AICI3 gives the desired amine in excellent yield. Benzylamines or their quaternary salts may also be utilized in appropriate solvents in place of benzylic chlorides, so that they too may act as nitrile precursors. ... 

Olefinic aldehydes have been synthesized by a variety of methods including oxidation of the corresponding primary alcohols with the chromium trioxide-pyridine complex 195—197) or N-chlorosuccinimide-dimethyl sulfide complex 198), heating a primary alken-l-yl mesylate with dimethylsulfoxide 199), or by alkylation of the lithium salt of 5,6-dihydro-2,4,4,6-tetramethyl-l,3-(4H)-oxazine with an alkynyl iodide followed by sodium borohydride reduction and acid hydrolysis (200). 

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