Dow Jones News Service quoted informed sources as saying that Minneapolis investor Irwin L. Jacobs is seeking partial liquidation of the giant company. Jacobs is a major ITT shareholder. The sources said that the partial liquidation would include spinning off many of the New York company's important assets, including Hartford Insurance Group and Sheraton Corp. to shareholders. Jacobs, who is chairman of Minstar Inc., met with ITT's chief financial officer, M. Cabell Woodward Jr., on Thursday and reportedly told him to "break the company up." Sources close to Jacobs indicated that his proposals were not well received by the company.