Buttner and his brother were in Moscow last week for talks with Dinamo.
The left-back's agent, Alexander Bursac, says the appointment of Louis van Gaal as new manager made up their mind - and they see Dinamo as a stepping stone to greater things.
"If you do not receive one phone call for the Oranje, then you should get out as soon as possible," Bursac told Omroep Gelderland.
"In three years he'll be top notch and so he can go to Real Madrid."
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