Chloromethyl chlorosulfate

It’s also used for making chloromethyl esters, phosphates, and prodrugs, and serves as an intermediate in drug synthesis for compounds like HIV inhibitors. Chloromethyl chlorosulfate (CMCS) is a key reagent in organic synthesis, mainly used for chloromethylation, introducing a (-text{CH}_{2}text{Cl}) group, especially for modifying amino acids (like Fmoc-protected ones) in pharmaceuticals and creating specialty chemicals, while avoiding the highly carcinogenic byproduct from traditional methods.