Kadlec recently signed a new long-term contract with Sparta Prague, after scoring 19 goals in all competitions.
Despite that deal, Frankfurt believe that they can add Kadlec to their squad before the transfer window closes, with a meeting scheduled to plan a fresh bid for the 21-year-old later this week.
Bruchhagen told Sport 1 TV: "There is the plan to see Bruno Hubner, our general manager, to finalise the transfer this week.
"I am happy to finally know how this will end up. We want this player to join our club, but Sparta Prague is unsure over agreeing a transfer."
Frankfurt finished sixth in the Bundesliga last season, earning a place in the Europa League qualifying round as a reward.