It is very hard to devise a compound-name search that will allow for all the possible ways in which a compound may be named. Try using name roots (e.g. thiazol rather than thiazolyl) or, if at all possible, do a substructure search instead. The advantage of compound-name searching is that it's usually quicker to type a name than to draw a substructure. Please be aware that it is not yet possible to exclusively search for an exact compound name since a search for an exact name will also retrieve all hits in which the compound name you specified is included, so, for example, a search for ferrocene will also retrieve acetyl-ferrocene.