The developers of the Portal Site in Southwest Washington yesterday rejected the District urban renewal agency's attempt to set the sales price for the tract and won additional time to negotiate with the city.

The extra time, granted at the urging of Ivanhoe Donaldson, the new deputy mayor for economic development, prevented the developers from losing the project this week. Last Thursday the Redevelopment Land Agency, over the developers' objections, gave the developers five days to agree to a minimum price of $45 million for the 10-acre tract or lose the project.

Yesterday, Donaldson, making his first appearance before the RLA board, asked that the five-day deadline for the developers' agreement to a price be thrown out because the two principal members of the Portal team, office building developer Melvin Lenkin and shopping center owner Theodore N. Lerner, were out of town.

The RLA, by trying to get the developers to agree to a sales price, was trying to avert a possible clash over price and protracted negotiations that had plagued other RLA developments, such as Metro Center, according to board sources.

Metro Center developers Oliver T. Carr and Theodore R. Hagans took the board to court after the two sides failed to reach an agreement over price and the agency tried to revoke the developers' rights to the downtown project. The developers and city officials reached an out-of-court settlement that the RLA is still discussing in private.

Donaldson, in his new role as deputy mayor, is the city's chief negotiator with the Portal developers.

Donaldson asked the board to delete the $45 million price from the resolution that will guide the negotiations, but the RLA members refused. Then Donaldson asked, "Does the board have some flexibility here on the price and if so what is it?"

Board member Stephen Klein replied that the onus was on both the developers and city officials who will negotiate the land price to justify any price below $45 million. The board voted unanimously to amend last week's resolution by reaffirming the $45 million price for the project but dropping the five-day deadline and the requirement that the developers accept that price.