Mazzarri leaves Napoli when his contract expires next month.
"I offered Mazzarri a two-year deal, but I immediately started evaluating my options," De Laurentiis stated on Wednesday.
"I've been looking into this for months because I knew that Mazzarri would leave.
"I have spoken to Rafael Benitez [Chelsea], Manuel Pellegrini [Malaga], Roberto Di Matteo, Jurgen Klopp [Borussia Dortmund] who told me he was unavailable until 2016, Laurent Blanc and Didier Deschamps [France].
"I've contacted a lot of Coaches because I wanted to understand the feeling between ourselves. Anyway, the Coach only makes 15 per cent of the difference."