If the deal is dead, which i doubt it will be, you know for a fact that United would send a brief out saying they were ending interest. There is no way, with rumours of Zorc wanting to release an official comment tomorrow, that United wouldn't put something out before he has the chance to say something.
If the deal was dead or the deadline was truly that firm that a deal wouldn't be reached, or couldn't be reached, then a brief would have gone out tonight before Dortmund even had chance to say anything on the matter.