The products formed by the reaction of benzenethiols with diketene in the presence of H 2 SO 4 are (E)-β-(arylthio) crotonic acids (2) and/or isomeric (Z)-β-(arylthio) crotonic acids and not, as has been reported, S-phenyl 3-oxobutanethioates (1). Compounds 1a–k, as the precursor of thiocoumarins, were prepared from benzenethiols and diketene in the presence of triethylamine. The reaction of 1 with various condensing agents has been examined to ...
