German chemical giant BASF AG (Aktiengesellschaft) has purchased the Cyanamid herbicide division of drug company American Home Products Corp. (AHP), based in Madison, N.J. BASF – Europe’s largest chemicals maker – will pay AHP $3.8 billion in cash and will assume certain debt. Analysts have placed the amount of debt at $100 million. In a separate transaction, AHP – a research-based pharmaceutical and health care products company – is selling certain products to an unrelated party for $28 million. Cyanamid makes herbicides, fungicides and pesticides.