The Boyz n the Hood director announced the news on his Instagram account late on Tuesday (07Apr15), a week after telling XXL magazine he had put the project on hold while he "figured out some things".
In his post, Singleton wrote, "The reason I am not making this picture is because the people involved aren't really respectful of the legacy of Tupac Amaru Shakur.
"Tupac was much more than a hip hop artist... He was a black man guided by his passions... Of most importance was his love of black people and culture... Something the people involved in this movie know nothing about."
Singleton, who directed Shakur in 1993 film Poetic Justice, still hopes to make his own Tupac Shakur project.
Carl Franklin, who directed hit films Devil With the Blue Dress and Out of Time, has replaced Singleton.
Shakur was killed in a drive-by shooting in Las Vegas in 1996.