Versatile solid-phase synthesis of s-arylisothioureas

Resin-bound amines 4a-m condense with di(benzotriazol-1-yl)methanimine 6 to give 1H-benzotriazole-1-carboximidamide resins 7a-m, which subsequently react with thiols 9a'-g' followed by cleavage affording nonprotected isothioureas 1aa'-mg' in high yields and with good purities. Analogous reactions with secondary amines activated with EtMgBr lead to guanidines 2a,b,e-g in moderate yields. Resin-bound isothioureas 1 are converted by acyl chlorides or carboxylic acids into acyl derivatives 12a-n in high yields and with good purities.