At his brief appearance at the Stamford courthouse early Tuesday afternoon, Alfred Butler, 59, pleaded not guilty to charges of first-degree sexual assault, unlawful restraint, interfering with a 911 call, second-degree threatening and second-degree harassment. During the arraignment, supervisory Assistant State's Attorney Steven Weiss said Butler had two prior arrests on his record involving rape charges. The woman, whose name is being withheld by police and redacted in police reports in order to protect her identity, said she was talking to a male friend on the telephone at about 11 p.m.