Synthesis of substituted alkoxythiophenes: Thiophene analogues of dazoxiben

The synthesis of the thiophene analogue of dazoxiben - one of the most sele ctive TXA(2)-synthase inhibitors - and its derivatization to a chlorinated, more lipophilic product is described. The ethylenoxy moiety was introduced via nucleophilic aromatic substitution of halogenated thiophene carboxylic esters, the imidazol residue, by use of a t-butoxy group as a synthon afte r ether cleavage and halogenation. Also, at this step chlorination of the t hiophene moiety was carried out. After ester hydrolysis the target compound s were obtained as hydrochlorides.