Download PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... A four-step synthesis of methyl 3-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-2-carboxylate from commercially available starting materials is presented. ... Reagents and conditions: (i) DMF, POCl3, NH2OH·HCl, 40°C; (ii) ethyl ... Reagents and conditions: (i) DMF, POCl3, NH2OH·HCl, ...