Eddie Murphy once said that the jokes and camaraderie between him, Richard Pryor, Redd Foxx, Robin Harris, and Della Reese behind the scenes were much funnier than anything that was in the film.
According to Gabi Tartakovsky's June 7, 2011 article "Harlem Nights (1989): Eddie Murphy and the Original Gangsters of Black Comedy" at the Pop Matters website, "Pryor's toning down the Sugar Ray character wasn't scripted as such, and Pryor believed his performance was the result of being bothered with a recent Multiple Sclerosis diagnosis, which he kept to himself at the time."
The vulgar, yet playful arguments between Redd Foxx and Della Reese on the set inspired Eddie Murphy to create a series starring the two. The result was The Royal Family (1991), which was Foxx's final project before his death.
In his autobiography, "Pryor Convictions and Other Life Sentences (1997)", Richard Pryor states that he "never connected with Eddie Murphy. People talked about how my work had influenced Eddie, and perhaps it did. But I always thought Eddie's comedy was mean. I used to say, "Eddie, be a little nice" and that would piss him off. I finished Harlem Nights thinking that Eddie didn't like me."