Sodium alkyl sulfate transfer

Alkyl Aryl Telluriums2 (Reduction with Thiourea Dioxide) To a solution of 1.0 mmol diaryl ditellurium in 7.5 ml tetrahydrofuran are added 0.108 g (1.0 mmol) thiourea dioxide, 30 mg 2HT (phase transfer reagent), and 2.0 mmol of the alkyl bromide. To this mixture are added 7.5 ml of a 50% aqueous solution of sodium hydroxide. The mixture is stirred for several hours at 20°. The organic phase is separated. The aqueous phase is extracted three times with 20 ml ethyl acetate. The organic phase and the ethyl acetate extracts are combined and dried with anhydrous magnesium sulfate. The mixture is filtered and the solvents evaporated from the filtrate. The residue is chromatographed on silica gel with ethyl acetate as mobile phase. 

N-Alkylation of 1,2,3-triazoles and benzotriazoles is readily achieved using (1) alkyl halides, dialkyl sulfates, diazoalkanes, and jS-tosylates or (2) the Mannich reaction. When alkyl halides are used, sodium alkoxide, sodium hydride, or sodium hydroxide is usually employed as the base. The N-alkylation of benzotriazole with alkyl halides proceeds efficiently using powdered NaOH as the base in DMF. The highest yields (80100%) of the alkylated benzotriazoles are obtained when a fourfold excess of NaOFl is employed. A-Alkylbenzotriazoles have been prepared from benzotriazole and alkyl halides using phase-transfer catalysts, e.g., KOFI, benzene, tetrabutyl-ammonium salts or KOH, benzene, polyethylene glycol. 

Coupling of a benzoic acid derivative under basic conditions is achieved with alkyl iodides," alkyl chlorides,dimethyl sulfate, or (l,1-dihydroperfluoroalkyl)phenyliodonium triflates. Common bases used arc potassium carbonate or sodium hydroxide (with phase-transfer catalyst). " Again, employing acid chlorides " - or anhydrides, " is the method of choice. The reaction can be performed without further activation, " " but in most cases the transformation takes place in the presence of the usual bases, triethylamine - " or pyridine " " " " " [in some cases 4-(dimethylamino)pyridine is added " ]. In a similar manner carbamates. thiocarbamates, " or thiocarbonates are synthesized. Perfluoropropcn-2-ol... 

Almost no 9,10-diaIkoxyphenanthrenes are known, and the quantities of those few made by other methods are either small or unstated. The best alternative procedure gave 9,10-dimethoxyphenanthrene when 9,10-phenanthrenequinone was combined first with sodium in diglyme and then with dimethyl sulfate, but the yield after two chromatographic purifications was 51 %. The only other reported alkylations of phenanthrene-9,10-diol are by 1-chloro-2-diethylaminoethane in 10% yield, f and by l,2-di(bromomethyl)benzene in 22% yield. s Unlike the procedure recorded here, none of these employ two-phase alkylations catalyzed by phase transfer agents." ... 

Ether synthesis. Ethers can be prepared in high yield by the reaction of primary or secondary alcohols with primary aUcyl chlorides in a two-phase system composed of excess 50% aqueous sodium hydroxide and the alkyl chloride functioning as the organic solvent. Tetra-n-butylammonium hydrogen sulfate (3-5 mole %) is used as the phase-transfer catalyst. Primary alcohols are alkylated in 3-4 hr secondary alcohols require longer reaction times or larger amounts of catalyst. Yields are unsatisfactory with secondary alkyl chlorides. 

Freedman and Dubois [ 1 ] have found that a variety of ethers can be prepared by the reaction of either primary or secondary alcohols with inexpensive primary alkyl chlorides in the presence of excess concentrated aqueous sodium hydroxide solution and tetrabutylammonium hydrogen sulfate as catalyst. The formation of -butyl n-hexyl ether is shown in equation 5.1. Typically, the 8 2 displacement reaction was not successful with secondary alkyl halides even under phase transfer conditions. 

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