The Washington Star is scheduled to publish the final edition in its 128-year history and go out of business today, despite last-minute salvage attempts and negotiations with prospective buyers that continued into last night.

Donald M. Wilson, vice president for corporate relations of Time, Inc., the Star's parent company, said late yesterday that it was "conceivable but highly unlikely" that the paper would be sold before the deadline for the scheduled last edition.

In the two weeks since Time announced its intention to discontinue publication of The Star, five dozen potential buyers expressed interest in the newspaper, including Karl Bendetsen, retired chairman of Champion International Corp., a paper manufacturing firm, who made a hurried proposal yesterday.

But only 11 offers were considered serious enough for face-to-face negotiations, Wilson said, and Bendetsen's was not among them.

Negotiations with Boston real estate developer Mortimer B. Zuckerman, the last person known to be seriously interested, failed to produce an agreement sources close to the talks said, because Zuckerman wanted Time Inc. to keep the paper operating and absorb its losses while he negotiated contracts with the workers' unions.

Wilson said none of the possible purchasers who have talked to Time in the last two weeks was willing to meet Time's demand for a commitment to keep the paper going for at least a year -- a commitment that could have cost $20 million, the amount Time says The Star has been losing yearly.

Most of 1,427 employes of the evening newspaper of the nation's capital were told that the paper's plant at 225 Virginia Ave. SE should be vacated by this afternoon, and the paper was eulogized by its columnists in yesterday's editions.

Today's editions, The Star announced, will include special sections commemorating the paper's history and reprinting some of the best work of the paper's reporters and cartoonists.

More copies than the usual 322,000 will be printed, and newsstands will be stocked with the memorial edition through the weekend, the paper announced in a modest front page box in yesterday's editions.

After two emotional weeks during which hopes for the paper's survival rose and fell, employes seemed resigned yesterday to its demise.

Workers in several departments held final get-togethers, but after Time Inc. posted a memo prohibiting alcoholic beverages in the building, several farewell parties were moved to homes and nearby bars -- the same Capitol Hill watering holes where generations of Star reporters, their day's work done, had long regaled their colleagues with tales of journalistic derring-do.

The death of The Star will leave the nation's capital the largest city in the United States with only one daily newspaper, The Washington Post. The reading habits of tens of thousands of metrolpolitan area residents are expected to change as The Post expands, the suburban Journal newspapers, begin daily publication Sept. 14 and dailies from Baltimore to Richmond increase their circulation in the Washington suburbs.

Time officials said when they announced the scheduled closing that they had talked with the country's major newspaper and communications chains and other organizations about buying The Star. But none was willing to take over a once-powerful institution that had been losing money and circulation for several years.Time bought the paper in 1978, and invested $85 million in it since then -- $35 million of which were declared after-tax losses.

Zuckerman, owner of the Atlantic Monthly, could not be reached yesterday for comment on the end of his talk with Time. Soruces familiar with the negotiations said he wanted to take on The Star's name and its plant and produce a slimmed down community-oriented tabloid, but could not reach agreement with Time on settling the claims of the employes who have had been laid off.

The proposal from Bendetsen caused a last-mintue flurry opf excitement, especially since in his announcement he claimed to have the backing of several prominent. Washingtonians and former government officials. The proposal even listed Charles B. Seib, former managing editor of The Star and former ombudsman of The Post, as editor of the new Star.

The were indications yesterday, however, that there was less to the proposal than met the eye. Bendetsen, 73, said that Time Inc. was "aware" of it but that there had been no direct negotiations, that Star employes had not been informed of it, and that he did not know when, of if, he would get a response.

He said it was not an offer to buy The Star but a proposal to raise funds to help Time continue to operatie it. Seib said he had been approached about the editorship, but no firm proposal had been made and he had heard nothing about it for a week.

Time officials have said they would not grant extensions of time or continue to publish the paper beyond this afternoon. If no deal has been completed by that time, they reiterated yesterday, The Washington Star will be closed.