Rennes have said that they are unwilling to sell him this season and he is worried that any delay will scupper the move.
"I am worried such a chance might not happen again," Escude said. "It's an incredible opportunity for me and this is what I want the Rennes directors to understand. A career in football is short and things are always going fast, that is why it is important to seize the opportunities when they come up.
"It is time for me to move on and reach another step in my career."
Rennes are asking for around £5.1million for the player while United are not willing to offer more than half that sum.
"I have been repeating since the season started that I wanted to leave, I will keep fighting to be heard," he added. I have spent three great seasons with Rennes but I have other objectives and ambitions now.
"Manchester knocked on my door and that makes me dream, makes me feel like going, this club is so prestigious. And if Rennes sell me it can only be beneficial to them, they will see their reputation grow thanks to that transfer. Ferguson contacted me personally, he did not do it just by pure chance, this means he watched me and decided he wanted me. Manchester is currently what is best in football, it is one of the greatest clubs in the world. When I was a kid I used to look at their games, I was in awe of them."