Accused swindling son Anthony Marshall failed yesterday in his last-ditch attempt to have all or some of his 18-count indictment dismissed — leaving his trial on track for Monday closing arguments.

Manhattan Supreme Court Justice Kirke Bartley denied defense motions to toss the conspiracy, grand-larceny and fraud charges alleging Marshall strong-armed his failing philanthropist mother, Brooke Astor, out of more than $60 million in gifts and bequests.

Marshall is fighting a possible 25-year prison sentence by insisting his mother gave him everything willingly. She died at 105 in 2007.