In a setback for the United States’ attempts to isolate Iran, the General Court in Brussels threw out sanctions Friday on seven Iranian companies, including four banks, rejecting arguments that they were acting as front companies to bypass the punitive measures. The United States Treasury took the opposite tack on Friday, imposing restrictions on a network of six individuals and four businesses for links to oil sales. These actions represent a renewed crackdown to curb the use of front companies, financial institutions and businesspeople to conceal the direct involvement of the Iranian government and entities like the National Iranian Oil Company and the Naftiran Intertrade Company. European officials are expected to hold initial discussions on whether to appeal on Tuesday.