The U.S. Court of Appeals has removed the latest legal stumbling block that delayed plans by the Pennsylvania Avenue Development Corp. to demolish the Munsey Building to make way for an 800-room hotel.

PADC's development director, Charles A. Gueli said yesterday that the redevelopment corporation will immediately ask the Distrcit of Columbia government for a permit to begin demolition of the graying, 12-story building, which is located just off Pennsylvania Avenue NW.

He said that there is a December deadline to clear the site for the Quadrangle Development Corp. and the Marriott Corp., the prespective builders of a $150 million complex planned for the block bounded by 13th, 14th, E and F streets.

An office building and a trilevel retail shopping complex also are planned for the block, which will be leveled except for the National Theater and the National Press Building.

City officials were about to issure a demolition permit last September when Don't Tear It Down, a local preservation group, filed a lawsuit to block demolition of the Munsey building. The action was postponed by court order while legal arguments were considered.

Don't Tear It Down had argued thatthe PADC was in violation of the D.C. Historic Protection Act, which says that permits for demolition in an historic district must be submitted to the city's Joint Committee on Landmarks. The preservationists contended that since the Pennsylvania Avenue plan does not explicitly call for demolition of the Munsey building, the committee should be allowed to consider whether the building could be retained and still be in compliance with plans for the corridor.

The PADC, which bought the MunseyBuilding in early 1979 for about $4 million, contended that the plan said that the building could remain standing as long as the owners chose not to develop it.

Redevelopment corporation contended that its plans were drawn up years before the Protection Act and thus were exempt from its requirements. The PADC also argued that no other federal or District of Columbia agency had authority to modify the Pennsylvania Avenue development plan, which permits demolition of the Munsey Building.

Last November, U.S. District Judge Aubrey E. Robinson Jr. ruled in favor of the PADC and said that the city government, which had supported the PADC, had reasonably interpreted its responsibilities under the Historic Protection Act.

In a brief, unsigned order issued Wednesday, the Appeals Court affirmed Judge Robinson's decision and lifted court orders that had blocked demolition moves. The Appeals Court said it would issue a written opinion in the case later.

Phyllis J. Cohen, an attorney who represents the preservationists, said her clients had filed the lawsuit in attempts with procedural requirements that were designed to assure full review of any demolition plans in the historic area before permits were granted.

She said yesterday that he clients now must decide whether to ask the full Apppeals Court to consider the issues or seek review in the U.S. Supreme Court. In the meantime, Cohen said, the preservationists could ask for additional court orders stopping demolition. CAPTION: Illustration, This is the architect's rendering of the 800-room, $150 million complex that the Quadrangle Development Corp. and the Marriot Corp. would build at Munsey site. Pennsylvania Avenue Developement Corporation