NEW YORK (AP) _ A teen-ager was sentenced today to 321/2 years to life in prison in the slaying of the first New York City policewoman killed in the line of duty.

As the sentence was read by Justice Thaddeus Owens in state Supreme Court, New York's trial-level court, some supporters of Darryl Jeter jumped up and chanted, ''Free Darryl.'' About 10 people, some of them waving placards, were hustled out of the courtroom by guards.

Jeter, 19, of Brooklyn, was sentenced for the Sept. 21 shooting of Irma Lozada, 25. He was sentenced to 25 years to life for the murder conviction and received a 71/2 - to 15-year term for weapons possession which is to be served consecutively.

He made no statement before he was sentenced. Assistant District Attorney Eric Seidel noted the probation report said Jeter had shown no remorse for the slying and reminded the judge of the ''viciousness, the cruelty, the needlessness'' of the death.

Defense Attorney Richard Foard III told the judge Jeter showed a lack of remorse ''because he denied having committed the crime in the first place.''

Owens denied a defense motion to set aside the verdict.

During the trial, Jeter maintained he was innocent and said another man from his neighborhood committed the crime. Miss Lozada's service revolver was recovered from a bedroom Jeter used, but he said he was merely keeping it for the other man.