Alkylations potassium hydroxide-dimethyl sulfoxide

Benedict, D. R., Bianchi, T. A., Cate, L. A. Synthesis of simple unsymmetrical ethers from alcohols and alkyl halides or sulfates the potassium hydroxide/dimethyl sulfoxide system. Synthesis 1979,428-429. 

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... 

Dipotassium telluride was obtained by heating tellurium, tin(II) chloride, and potassium hydroxide in dimethyl sulfoxide at 120° for 20 hours. Alkylation of the dipotassium telluride with methyl iodide gave dimethyl tellurium in almost quantitative yield1. 

A modification of this general procedure was used in the synthesis of (prop-2-enylidene)cyclo-propane (allylidenecyclopropane, 12).Allyl bromide was first alkylated in 81 -90% yield with l-lithio-l-(phenylsulfanyl)cyclopropane (10) in the presence of copper(I) iodide or cop-per(I) iodide-dimethyl sulfide. The adduct was then methylated with methyl fluorosulfonate or with dimethyl sulfate, and the sulfonium salt cleaved with powdered potassium hydroxide in dimethyl sulfoxide, to give the product in 50-70% overall yield for the second step. 

For the TMAH alkylaticm procedure, 100 micrograms of drug were combined with 200 microliters of a 50/50 mixture of dimethyl sulfoxide and 0.2M TMAH in methanol and 100 microliters of the appropriate alkyl halide. The mixture was allowed to stand at room temperature for 4 minutes and then heated for 4 to 6 minutes in a 60° C water bath. After the mixture was allowed to cool to room temperature, 3 milliliters of hexanes were added, vortexed briefly, and then 1 milliliter of 0.1 N potassium hydroxide was added and vortexed once again. After centrifugaticm, the top hexanes layer was transferred to a clean test tube and the hexanes layer was concentrated to approximately 200 microliters. Approximately I to 2 microliters were injected into the GC/MS instrument using the ccMiditions described above. 

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