The Reagan administration announced a number of high-level executive branch appointments yesterday.

Donald J. Quigg, deputy commissioner of patents and trademarks in the Commerce Department since 1981, was nominated to be commissioner of the Patent and Trademark Office.

Quigley previously served as patent counsel to Phillips Petroleum Co. He would succeed Gerald Mossinghoff.

Charles O. Sethness, associate dean of Harvard Business School for external relations, was nominated to be assistant secretary of the Treasury for domestic finance. Sethness would replace Thomas J. Healey, who resigned in March.

Meanwhile, Carole J. Dineen, fiscal assistant secretary of the Treasury, was appointed associate director of the Office of Management and Budget for administration. Dineen, a former vice president with Banker's Trust Co. in New York, has been in charge of the administration's cash management efforts. She will replace Arlene Triplett, who left OMB to join McManis Associates Inc., a Washington-based consulting firm.

In addition, President Reagan nominated J. Cameron Argetsinger II, general counsel of Action, to a seat on the Copyright Royalty Tribunal.

Argetsinger is a former staff member of the Senate Judiciary Committee and an aide to Sens. Larry Pressler (R-S.D.) and Frank H. Murkowski (R-Alaska).