Philadelphia-based Pennwalt Corp. told its shareholders to...

Philadelphia-based Pennwalt Corp. told its shareholders to ignore New York-based Centaur Partners’ $100 a share buyout offer until the chemical company’s board of directors responds to it . . . CBS Inc., New York, said it tentatively had agreed to buy two radio stations in Detroit, WWJ-AM and WJOI-FM, from Federal Broadcasting Co. for an undisclosed price . . . CalMat Co. of Los Angeles has agreed in principle to sell a major portion of its income-producing properties in California and Arizona to Shidler Group for $112 million.