Dimethylsulfoxide, with potassium

The primary synthetic route proceeds via oxidative dimerization of 2-aminoan-thraquinone in the presence of an alkali hydroxide. 2-aminoanthraquinone, for instance, is fused with potassium hydroxide/sodium hydroxide at 220 to 225°C in the presence of sodium nitrate as an oxidant. New techniques involve air oxidation of 1-aminoanthraquinone at 210 to 220°C in a potassium phenolate/sodium acetate melt or in the presence of small amounts of dimethylsulfoxide. A certain amount of water which is formed during the reaction may be removed by distillation in order to improve both efficiency and yield. 

A wide range of polymer reagents have been studied [Akelah and Sherrington, 1983 Blossey and Ford, 1989 Ford, 1986a Kirschning et al., 2001], The epoxidation of an alkene by a polymer peracid illustrates the use of a polymer reagent [Frechet and Haque, 1975]. Chloro-methylated polystyrene is treated with potassium bicarbonate in dimethylsulfoxide to yield... 

Propyleine (104) also is derivable from ketone 437. Reduction of 437 with LAH gave the equatorial alcohol (438) which was converted into the corresponding mesylate (439). Clean elimination was effected by heating 439 with potassium carbonate in dimethylsulfoxide to yield a 3 1 mixture of propyleine (104) and isopropyleine (440) (Scheme 54) 455). 

Thus, with methyl and also ethyl cyanoacetate, the anilinomethylene chromonedione (220) (this form has been found94 to predominate in dimethylsulfoxide solution rather than the tautomeric structure of the formal SchifFs base from 3-formyl-4-hydroxycoumarin and aniline) yields, initially, with potassium hydroxide in DMF, following hydrolysis, the pyronocoumarin 221. 

The one-electron reduction of 3,4,5-trimethoxyphenyl glyoxal with potassium tert-butoxide in dimethylsulfoxide gives rise mainly to the cis-semidione, while upon electrolysis in dimethylformamide, in the presence of tetraethyl ammonium perchlorate as the carrier electrolyte, the main product is the trans isomer (Sundaresan Wallwork 1972), Scheme 3-41. 

Oxaspiropentanes have been obtained from the cyclopropylide 103, prepared by treatment of cyclopropyldiphenylsulfonium tetrafluoroborate 102 either with sodium methylsulfmyl carbanion in dimethoxyethane at —45 °C or with potassium hydroxide in dimethylsulfoxide at 25 °C. While the reaction of the ylide 103 with a,p-unsaturated carbonyl compounds has resulted in selective cyclopropylidene transfer to the a, 3-carbon-carbon double bond leading to spiropentanes, condensation of 103 with non-conjugated aldehydes and ketones led to oxaspiropentanes such as 104, which have been isolated in 59-100% yields, Eq. (30) 57). 

The very well established chemical technique of using potassium superoxide or ammonium superoxide suffers from the pH instability described in reactions (15) to (17) the superoxide is only stable at very high pH, or the use of an organic solvent, most often dimethyl-sulfoxide (DMSO). Still a great number of very impressive studies were carried out using stopped flow technique combined with potassium superoxide in dimethylsulfoxide, particularly by Fee and co-workers and then by Silverman and co-workers. ... 

Abstraction of bromine from a cyclopropane ring fused to another ring gives variable amounts of alkenylcyclopropanes, depending on the size of the second ring. Thus, reaction of 7-bro-mobicyclo[4.1.0]heptane (7) with potassium tert-butoxide in dimethylsulfoxide gave a 24% yield of bicyclo[4.1.0]hept-2-ene (8) (see also Section 5.2.2.1.1.2.). 

When chloromethylated crosslinked polystyrene is reacted with potassium superoxide, the yield depends upon the type of solvent used. In dimethylsulfoxide, in the presence of 18-crown-6 ether, the conversion to hydroxymethyl groups is 45%. In benzene, however, it is only 25%. High conversions are obtained by catalyzing the reaction with tetrabutylammonium iodide in a mixture of solvents. This results in 85% conversions to hydroxymethyl groups, while the rest become iodide groups. 

Synthesis started with the reaction of commercially available 2-methoxy-4-nitroaniline, 1, with potassium hydroxide in aqueous dimethylsulfoxide to yield a phenol (2). The phenol was alkylated with dibromotetrafluoroethane following the general route described by Rico and Waskselman to give 2 (8). The addition of a catalytic amount of propanethiol is required for this reaction to proceed since it assists in the in-situ generation of tetrafluoroethylene, the electrophile in the reaction. 

Diphenylmethane reacts with dioxygen in the presence of potassium 1,1-dimethylethoxide in various solvents (dimethylformamide [DMF], hexamethylphosphoramide [HMPA], pyridine) to produce nearly 100% yields of benzophenone [284]. The adduct of benzophenone with dimethylsulfoxide (DMSO) [l,l-diphenyl-2-(methylsulfinyl)ethanol] is formed as the final product of the reaction. The stoichiometry of the reaction and the initial rate depends on the solvent (conditions 300 K, [Ph2CH2] = 0.1mol L [Me3COK] = 0.2mol L 1,p02 = 97kPa). 

Probl0m 7.51 Potassium /er/-butoxide, K OCMCj, is used as a base in E2 reactions, (a) How does it compare in effectiveness with ethylamine, CHjCH NH (f>) Compare its effectiveness in the solvents fert-butyl alcohol and dimethylsulfoxide (DMSO) (c) Give the major alkene product when it reacts with (CH JjCClCHjCH,. 

An aqueous solution of potassium tetrachloroplatinate(II) (1.24 gg, 3 mmol in 10 mL) is filtered into a 50-mL beaker through paper. This procedure removes impurities due to metallic Pt and/or K2PtCl6. Dimethylsulfoxide (0.64 mL, 9 mmol) is added to this solution and, after a gentle hand mixing, the solution is left to stand at room temperature until complete precipitation of yellow needles. The precipitate is filtered, washed with several 5- to 10-mL aliquots of water, ethanol, and diethyl ether, and dried in vacuo for 4 h. The yield is 1.10 g (87% based on K2PtCl4). 

To a 250 ml flask equipped with a stirrer, a thermometer, a water condenser and Dean-Stark trap was added 11.42 g of 4.4 -isopropylidenediphenol (0.05 moles), 13.1 g of a 42.8% potassium hydroxide solution (0.1 mole KOH), 50 ml of dimethyl sulfoxide and 6 ml of benzene. The reaction mixture was kept under an atmosphere of nitrogen and the water was azeotroped oft over a 3 to 4 hours period (130—135° C). At the end of this time the reaction mixture consisted of the potassium salt of the biphenol and was essentially anhydrous. After cooling the mixture there was added 14.35 g (0.05 moles) of 4.4 -dichlorodiphenyl sulfone and 40 ml of anhydrous dimethylsulfoxide. The reaction mixture was maintained, under a nitrogen atmosphere, between 130 and 140° C with stirring for 4 to 5 hours. The viscous orange solution was then poured into 300 ml of water in a Waring Blendor and the polymer separated by filtration and dried at 110° for 16 hours. A yield of 22.2 g (100%) of polymer with a reduced viscosity in chloroform (0.2 g per 100 ml at 25°) of 0.59 was obtained. 

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