City have been linked with the Chile international throughout the window , with his contract at the Emirates Stadium due to expire at the end of the season.
Pep Guardiola's side have had a £50 million offer rejected , but could come back with a fresh bid amid speculation Arsenal want winger Raheem Sterling to be part of the deal.
De Bruyne is a fan of Sanchez's ability and feels he would be a positive addition to cap what he believes has been an ideal transfer campaign for City.
"He's a very good player obviously but I don't know what's happening about the other transfers," De Bruyne said to Sky Sports .
"I think City is doing the business perfectly this summer and if they want him they will try everything to get him.
"And if he comes to us that's a good addition."
Sanchez returned from injury to play his first match of the season against Liverpool on Sunday, but Arsenal went down to a humiliating 4-0 defeat.
De Bruyne sympathises with Sanchez, who has faced a close-season of uncertainty and speculation. The Belgium international sees similarities with his own protracted move to City from Wolfsburg in 2015.
"A quick transfer is good," said De Bruyne. "If it drags on it can be annoying and I had to wait two or three weeks to join City.
"Every time you go home everyone asks, 'What's happening?' You say you're going, then the next day you say you're staying - it can be annoying.
"Everyone needs to be happy, both teams, the players. But when it's over, everyone is relieved."
The transfer window in England closes on Thursday at 23:00 BST.