Chloromethyl chlorosulfate

Clear colourless to yellow liquid

Reagent for chloromethylation of Fmoc-protected amino acids without the generation of carcinogenic bis(chloromethyl)ether.

1) reacting liquid sulfur trioxide with methylene chloride for 1 to 24 hours at -50 to 40 C. in the presence of a catalyst carbonate, a saturated hydrocarbon base carbonate containing saturated hydrocarbon base, a borate salt, and a borate containing saturated hydrocarbon base to produce a mixture of chloromethyl chlorosulfonate and methyldichlorosulfonate;

2) putting sodium bicarbonate or an aqueous sodium bicarbonate solution into the mixture obtained from step 1) above to remove the excessive amount of Sulfur trioxide and the sulfuric acid produced by hygroscopicity, so that the reaction continues;

3) put sodium bicarbonate or an aqueous sodium bicarbonate solution into the mixture obtained in step 2) above, completely remove the excessive sulfur trioxide and the sulfuric acid produced by hygroscopicity, static layering, take the upper organic layer to dry to remove the solvent and distill under reduced pressure, to obtain chloromethyl chlorosulfonate and methyldichlorosulfonate, respectively.