Methoxyethoxy -ethyl 2- Chlorosulfonyl -benzoate

Achille Barco, Simonetta Benetti Gian P. Pollini 

Solubility soluble in methylene chloride, ethyl ether, alcohol, and most other organic solvents not soluble in H2O. 

Form Supplied in colorless oil not currently commercially available. 

Procedure 1 A mixture of sulfobenzoic acid anhydride (1.0 equiv) and phosphorus pentachloride (2.0 equiv) was heated at 90 °C for 6 h. The oil was allowed to cool, dissolved in ether, and rinsed with ice water to remove umeacted phosphorus pentachloride. The solvent was evaporated in vacuo. The crude oil (1.0 equiv) was then dissolved in excess 2-(2-methoxyethoxy) ethanol (5.0 equiv) and heated to 60 °C for 30 h. The reaction mixture was purified by flash chromatography by eluting with a hexane/acetone (85 15 v/v) to yield the sulfonyl chloride as a colorless oil (95% yield). 

Sulfonate ester NALGs are prepared via a DMAP-catalyzed addition of alcohols to 2-(2-methoxyethoxy)-ethyl 2-(chlorosulfonyl) benzoate (eq 2). For more hindered cases, the alcohol was first converted to the sodium alkoxide using NaH followed by the addition of 2-(2-methoxyethoxy)-ethyl 2-(chlorosulfonyl) benzoate. For the most hindered alcohols, both DMAP and NaH were used to give the sulfonate product (NALG) in good yields (80-95%) with shorter reaction times. In all cases, sulfonate NALGs were exceptionally stable to aqueous workup and silica gel chromatography.  

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