Sulfoxide, dimethyl

Water Less than 0.04% by Karl Fischer titration Ultraviolet absorbance  

Water Less than 0.05% by Karl Fischer tltretlon Ultraviolet absorbance  

Peroxides Less than two mg/1 es H2O2 at time of packaging 

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The formation of the above anions ("enolate type) depend on equilibria between the carbon compounds, the base, and the solvent. To ensure a substantial concentration of the anionic synthons in solution the pA" of both the conjugated acid of the base and of the solvent must be higher than the pAT -value of the carbon compound. Alkali hydroxides in water (p/T, 16), alkoxides in the corresponding alcohols (pAT, 20), sodium amide in liquid ammonia (pATj 35), dimsyl sodium in dimethyl sulfoxide (pAT, = 35), sodium hydride, lithium amides, or lithium alkyls in ether or hydrocarbon solvents (pAT, > 40) are common combinations used in synthesis. Sometimes the bases (e.g. methoxides, amides, lithium alkyls) react as nucleophiles, in other words they do not abstract a proton, but their anion undergoes addition and substitution reactions with the carbon compound. If such is the case, sterically hindered bases are employed. A few examples are given below (H.O. House, 1972 I. Kuwajima, 1976). 

The widely used Moifatt-Pfltzner oxidation works with in situ formed adducts of dimethyl sulfoxide with dehydrating agents, e.g. DCC, AcjO, SO], P4O10, CCXTl] (K.E, Pfitzner, 1965 A.H. Fenselau, 1966 K.T. Joseph, 1967 J.G. Moffatt, 1971 D. Martin, 1971) or oxalyl dichloride (Swem oxidation M. Nakatsuka, 1990). A classical procedure is the Oppenauer oxidation with ketones and aluminum alkoxide catalysts (C. Djerassi, 1951 H. Lehmann, 1975). All of these reagents also oxidize secondary alcohols to ketones but do not attack C = C double bonds or activated C —H bonds. 

Dimethyl sulfoxide has the structure (CH3)2 —0 and is commonly referred to as DMSO It IS a relatively inexpensive solvent ob tamed as a byproduct in paper manufacture... 

Similarly sodium methoxide (NaOCHj) is a suitable base and is used m methyl alco hoi Potassium hydroxide m ethyl alcohol is another base-solvent combination often employed m the dehydrohalogenation of alkyl halides Potassium tert butoxide [K0C(CH3)3] is the preferred base when the alkyl halide is primary it is used m either tert butyl alcohol or dimethyl sulfoxide as solvent... 

Compound A (C4H10) gives two different monochlondes on photochemical chlorination Treatment of either of these monochlondes with potassium tert butoxide in dimethyl sulfoxide gives the same alkene B (CaHg) as the only product What are the structures of compound A the two monochlondes and alkene B2... 

Compounds A and B are isomers of molecular formula C9Hi9Br Both yield the same alkene C as the exclusive product of elimination on being treated with potassium tert butoxide in dimethyl sulfoxide Hydrogenation of alkene C gives 2 3 3 4 tetramethylpentane What are the structures of compounds A and B and alkene C2... 

When the reaction was earned out m aqueous methanol as the solvent hexyl bromide was converted to hexyl cyanide m 71% yield by heating with sodium cyanide Although this IS a perfectly acceptable synthetic reaction a peiiod of ovei 20 hours was lequued Changing the solvent to dimethyl sulfoxide brought about an increase m the reaction rate... 

Double dehydrohalogenation to form terminal alkynes may also be carried out by heating geminal and vicinal dihalides with potassium tert butoxide m dimethyl sulfoxide... 

When 1 2 dibromodecane was treated with potassium hydroxide m aqueous ethanol it yielded a mixture of three isomenc compounds of molecular formula CioHi9Br Each of these compounds was converted to 1 decyne on reaction with sodium amide m dimethyl sulfoxide Men tify these three compounds... 

Find the model of dimethyl sulfoxide [(CH3)2S=0] on Learning By Modeling and exam me Its electrostatic potential map To which atom (S or O) would you expect a proton to bond d... 

Wittig reactions may be carried out m a number of different solvents normally tetrahydrofuran (THF) or dimethyl sulfoxide (DMSO) is used... 

Suitable strong bases include the sodium salt of dimethyl sulfoxide (m dimethyl sulfox ide as the solvent) and organohthmm reagents (m diethyl ether or tetrahydrofuran)... 

The reaction is of the 8 2 type and works best with primary and secondary alkyl halides Elimination is the only reaction observed with tertiary alkyl halides Aryl and vinyl halides do not react Dimethyl sulfoxide is the preferred solvent for this reaction but alcohols and water-alcohol mixtures have also been used... 

Potassium tert butoxide reacts with halobenzenes on heating in dimethyl sulfoxide to give ten butyl phenyl ether... 

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