Complex sentence: In 1977, when Donald Rumsfeld was president of the Searle corporation, the FDA was reportedly reluctant to legalize aspartame (NutraSweet) because of adverse effects on animals in testing.
Split into simpler sentences: In 1977, Donald Rumsfeld was president of the Searle corporation. The FDA did not want to legalize aspartame (NutraSweet) because of its adverse effects on animals in testing.