Mr Zingarevich bought 51% of Reading in May 2012 and was due to complete a full takeover of the club in October last year.
However, the Russian has pulled out of the deal and the club have been looking for new investment ever since.
Madejski said in a statement. "There has been plenty of interest but no firm offers,"
Christopher Samuelson and Andrew Obolensky of Thames Sports Initiatives (TSI) have also left Reading's board as talks are taking place with potential new owners.
Israeli entrepreneur Teddy Sagi, who made his fortune in gaming software, and Indian businessman Mohit Burman, who is part-owner of IPL cricket team Kings XI Punjab, are reportedly interested in owning the Championship club.
Israeli entrepreneur Teffy Sagi, who made his money in gaming software, and Indian Businessman Mohit Burman, who is part-owner of IPL cricket team Kings XI Punjab, are reportedly interested in owning the Royals.
Madejski recently admitted new investment was critical, while striker Adam Le Fondre was sold to Cardiff City last week to help pay an outstanding tax bill to HM Revenue and Customs.