“…In the reaction of o-aminothiophenol with chalcones in refluxing toluene, from chalcones with electron-donating substituents such as methyl and methoxy group, only b-phenyl-b-(2-aminophenylmercapto)-propiophenones were formed, whereas from chalcones with electron-withdrawing substituents such as nitro group, only 1,5-benzothiazepines were formed. [16] In contrast, the reaction using silica gel under solvent-free conditions gave only 1,5-benzothiazepines in good yield independent of the chalcone substituents, with the exception of nitro and hydroxy groups. In the case of chalcones having nitro and hydroxy groups, the yields were lower than that of chalcones with the other substituents.…”