Synthesis and cathodic cleavage of a set of substituted benzenesulfonamides including the corresponding tert-butyl sulfonylcarbamates: pK a of sulfonamides

摘要: From a series of substituted benzenesulfonic acids, most which have previously been employed for the protection amino functions and including few such known to facilitate cleavage by acid, benzylamides 1a–k derived studied. Initially their electrochemical potentials were determined cyclic voltammetry in order further explore selective deprotection within this substance group. In parallel, corresponding tert-butyl sulfonylcarbamates 2a–k also prepared Among sulfonamides investigated S–N bond was found take place over wide range from –1.67 –2.64 V (excluding nitro derivative), acid-labile groups requiring more negative potentials, whereas facilitated 0.19–0.30 sulfonylcarbamates. Small scale electrolyses 2 at controlled potential with determination products formed subsequently performed. For N-benzylbenzenesulfonamides 1, pKas DMSO some cases water be 14.0–16.4 10.07–11.53, respectively.