The Iron have already had an undisclosed offer for the Minstermen's top scorer turned down, and the 22-year-old striker has been valued at £500,000 by the Conference high-fliers.
However, his contract expires in the summer and he has rejected the offer of a new deal at KitKat Crescent.
The Iron are eager to quickly replace Keogh, who completed a £600,000 move to Wolves on Tuesday.
"We have watched him several times this season and he is someone we noticed last year as well," Adkins told the Scunthorpe Telegraph.
"But we will not offer stupid money, especially for a player who is out of contract in the summer.
"We have been targeting several players, Donaldson is not the only one, and have missed out on a couple who have gone to other clubs for transfer fees."
Peterborough and Accrington have both had six-figure bids rejected for the former Hull City junior, who has notched 20 goals so far this season.