O-(Aminosulfonylation) of phenols and an example of slow hydrolytic release

Sequential replacement of imidazole from sulfonyldiimidazole by phenols and then amines leads to O-arylsulfamate esters. Application of this coupling method to 19 phenols and 6 amines generates a library of 114 sulfamate esters, Ar-OSO2-NR2. A sulfamate based conjugate of ethinyl estradiol was prepared by using the steroid 3-hydroxyl as the phenol component, and an amino amide derived from linoleic acid as the amine. Hydrolysis of this conjugate was studied in aqueous buffer at pH values 2, 5, and 7.4, and (essentially identical) respective half-lives of 6.8, 6.6, and 6.7 days were observed.