Download full text in 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. ... Approaches to the synthesis of 12-thiasteroids: synthesis of B-nor-6,12-bisthiaestra-1,3,5(10) ,8,14-pentaen-17-one. ... A new approach to the total synthesis of 12-thiasteroids has led to the synthesis of B-nor-6,12-bisthiaestra-1,3,5(10),8,14-pentaen-17-one(16).