President Reagan took some time from his semi-social visit to New York over the weekend to announce a few more appointments, including that of J. William Middendorf II to be the U.S. representative, with ambassadorial status, to the Organization of American States.

It had been assumed that Middendorf, the president of Financial General Bankshares Inc. who headed up the transition team at the Central Intelligence Agency, would get an administration job of some sort. The former ambassador and Navy secretary wanted to be defense secretary, but that didn't work out.

Reagan also announced nomination of Henry Catto Jr., chairman of Washington's IBIS Corp., board chairman of the Washington Journalism Review and a former ambassador to El Salvador, as assistant secretary of defense for public affairs. In another Defense Department appointment, Reagan named Russell A. Rourke, an administrative assistant to Rep. Harold Sawyer (R-Mich.), as assistant secretary for legislative affairs. Rourke was a presidential assistant for legislative affairs during the Ford administration. Other weekend appointments:

As expected, Mary C. Jarratt, a staff member on the House Agriculture Committee, will be assistant secretary of agriculture for food and consumer services.

William Heffelfinger, director of administration at the Department of Energy, will be assistant secretary of energy for administration, procurement, comptroller and finance.

Frederick Morris Bush as assistant secretary of commerce for tourism. Bush was national director of the George Bush for President Committee, staff assistant to the Reagan-Bush Committee and a transition aide to Bush. He is from Houston, but is no relation to the vice president