The Premier League minnows have emerged as surprise candidates to land the Spanish front-man's signature, with Roma, Stuttgart and Zenit St. Petersburg also believed to be interested.
Hull, who were continually frustrated in the transfer market earlier this summer - seeing moves for Michael Owen, Bobby Zamora and Fraizer Campbell all fall through - have enjoyed greater success in the past week, recruiting Villarreal striker Jozy Altidore, Algerian forward Kamel Ghilas and Reading midfielder Stephen Hunt.
The KC Stadium outfit are keen not to end their spending there, with a club record £12 million fee thought to have been made for Negredo, who bagged 32 league goals in 70 outings for Almeria, leading to speculation linking him with Liverpool and Tottenham Hotspur.
And boss Brown has revealed that although talks between Hull and Real are progressing frustratingly slowly, he remains confident of completing the deal.
"It has been four to six weeks since we first started speaking to Real Madrid but it is hard dealing with a club of that stature," he said.
"In terms of European football they are number one, two or three.
"There are times when you think it is 95 percent certain and then something happens and it's 50-50 again. But we're still working on it."
However, the Tigers' pursuit of the striker may yet end in disappointment, after the player's agent Alejandro Camano announced that Negredo would prefer a move to Serie A side Roma, who want to land the forward on loan.
"Negredo wants Roma," he told Corriere dello Sport.
"We are ready to wait for Roma for another two or three days, [sporting director] Daniele Prade knows all this, as he knows the player's choice would be the Giallorossi shirt. Negredo would be honoured to play for Roma.
"But Real, in the light of offers that they have received, now prefer to sell him.
"And now it is up to the Giallorossi to come into the race, opening talks with the Madrid management."
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NEWS: Stuttgart set sights on Negredo
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