All alliance between the U.S. Jewish lobby and U.S. business leaders aimed at avoiding a political donnybrook over legislation against the Arab boycott appeared to be collapsing yesterday.

A collapse could lead to a congressional anti-boycott bill that the business community would strongly oppose, producing a dilemma for President Carter, who denounced the boycott in strong terms during his campaign.

The legislation now being studied in COngress is designed to make it illegal for an American firm to participate in a boycott of Israel or of any American firms doing business with Israel in order to do business with the Arab nations.

Irving S. Shapiro, who endorsed the joint position on behalf of the Business Roundtable, said yesterday that the Anti-Defamation League of B'nai Brith "has essentially deserted" the agreed-upon position.

"This was a romance that has out-lived its usefulness," said Shapiro, the chairman of E.I. du pont de Nemours & Co.

Burton M. Joseph, the national chairman of the Anti-Defamation League, said he is "as encouraged as I've been in some time" that the joint principles will hold. "Our effort is joint", he said. Four areas of disagreement have been reduced to one over the past 48 hours, he added.

"Of course," Shapiro agreed. "The three areas were theirs and the one is ours."

Shapiro called the breakdown "a sad, unhappy situation" and said that the Anti-Defamation League's David Brody was feeding amendments to the Senate Banking Committee in violation of the ADL-Business Roundtable agreement. The roundable is an organization of 170 chief executives of American Businesses.

Sen. Adlai E. Stevenson III (D-III) said Brody and other lobbists took over desks and telephones in the Banking Committee's chambers during the mark-up sessions Wednesday ang Thursday.

Stevenson is a sponsor of a compromise on the main issue called "unilateral selection" over which the ADL-roundtable alliance is coming apart.

"Unilateral selection" is a murky area, but in general it refers to the right of a foreign nation to instruct a U.S. contractor which subcontractors or suppliers he may use. The ADL-roundtable principles permitted such instructions. The Stevenson compromise permits thtm in some cases.

While the wrangle in the Senate committee is expected to continue next week, the House International Relations Committee approved a bill that allows companies greater freedom to comply with a boycott than does the Senate version.

The House bill would force a company not to comply with unilateral selection only when it can prove that the selection has the sole purpose of enforcing the boycott, a difficule proof to make.

The House action would also permit U.S. companies' foreign subsidiaries to make otherwise forbidden complicance in other ways if they first received presidential approval.

The White House applied strong pressure to avoid a bill it considered potentially too damaging to U.S. trade with the Arab world.

Stevenson said he feares that if the ADL switched its positions a number of senators might also switch, ensuring an anti-boycott bill that would unnecessarily desprive Americans of Commercial opportunities.

"What started as an effort to protect the United States from Arab pressures is ending up an effort to defend the U.S. government from Israeli pressures," he charged.

Brody said it was no secret that he was-attending the Banking Committee mark-up sessions on the bill but said he didn't think his actions there were out of line with the agreed-upon principles. He referred further questions to Joseph.

"If there is any independent lobbying going on," Joseph said, "we will have to put a stop to it."

He also said that his group is working very closely with Jewish organizations and expects them to follow the ADL's lead on the boycott legislation.

Joseph suggestedthat a reporter telephone Shapiro again to check whether the Dupont chairman's pessimism had been moderated.

Shapiro reiterated that he believes the agreement its coming apart.

"We're back on the old treadmill of working up the old emotions, and disregarding the interests of the U.S. Firms that do business in the Middle East," Shapiro said.

He predicted that these businesses could not live with the bill that will emerge from the Senate Banking Committee and said he hoped that Carter, despite his campigh rhetoric, would not approve such a bill.

The Banking Committee chairman, Sen. William Proxmire (D-Wis), has made it clear he believes the ADL-roundtable position would permit U.S. companies to discriminate against firms on the Arab blacklist through the unilateral selection processthat gives the Arab country the right to choose participants in a large contract.