PHARMACEUTICALS

Hoechst Celanese to Buy Copley Stake: Hoechst Celanese Corp. has agreed to acquire 51% of Copley Pharmaceutical Inc. in a $546-million transaction that catapults Hoechst Celanese into the fast-growing generic drug industry. Under the agreement announced Saturday, Somerville, N.J.-based Hoechst Celanese will set up a new subsidiary and pay $55 a share in cash for 9.93 million outstanding shares of Copley Pharmaceutical’s stock. Hoechst Celanese is a wholly owned unit of Hoechst, the Frankfurt, Germany-based chemical and drug concern. Canton, Mass.-based Copley makes generic and over-the-counter pharmaceuticals. Both companies’ boards of directors have approved the purchase, a Hoechst Celanese spokeswoman said.