The U.S. Supreme Court and a federal appeals court turned down two appeals yesterday to delay the Friday execution of Virginia murderer Linwood E. Briley for the 1979 shooting death of a popular Richmond disc jockey.

The Supreme Court, by a 7-to-2 vote, rejected Briley's claim that he should be given a new trial because the jury was not aware of the plea agareement that was made with the state's chief witness.The 4th U.S. Circuit Court of Appeals rejected that argument last August, but the panel stopped Briley's scheduled Aug. 17 execution to consider the appeal.

Meanwhile, the 4th Circuit Court, meeting yesterday in Charlotte, N.C., denied a separate appeal in which Briley's attorneys claimed the jury was biased because there were no opponents of capital punishment on it. They also argued that Briley was discriminated against because he is black and his victim was white.

Briley, 30, is scheduled to be executed at 11 p.m. Friday for the 1979 murder of country-western disc jockey John (Johnny G) Gallaher. Briley has been convicted of committing five additional murders.

Also yesterday, the Supreme Court rejected an appeal by a Maryland woman, who was sentenced to die in the state's gas chamber for helping her husband rape his brother's stepdaughter and then strangling her.

Annette Stebbing, the first woman sentenced to death under Maryland's new capital punishment law, was convicted in Hartford County, after confessing that she held down Dena Polis, 19, while Bernard Stebbing raped her. Annette Stebbing told police, "I strangled her until there was no life in her."

Briley's arguments before the 4th Circuit Court yesterday marked the fourth round of appeals before that court in his fight to avoid the electric chair. The three-judge appeals panel that spent an hour hearing the latest arguments comprised Donald Russell, K. K. Hall and Emory Widener Jr., the same judges who considered and rejected his plea last August.

Defense attorney William Allen said yesterday that he would seek a stay from the 4th Circuit in order to prepare another appeal to the Supreme Court before Friday.

Before the 4th Circuit ruling, the state's Senior Assistant Attorney General James Kulp said, "We think Linwood will probably be executed Friday if the court rules in our favor this morning."

He said that state attorneys believe this is the last round of appeals, or the "last obstacle," and that he expected Briley's attorneys to go again to the Supreme Court.

If Briley is excecuted as scheduled, it would be the second Virginia execution in 24 years. Frank Coppola, a former Portsmouth policeman, was killed Aug. 10, 1982, for the murder of a Newport News woman.

Briley and his brother James led four other death row inmates in a May 31 escape from Mecklenburg Correctional Center near Boydton, Va. The Briley's, the last to be recaptured, were arrested on June 19 in Philadelphia.