Complex sentence: Glucuronolactone has received some notoriety due to an urban legend that it was a Vietnam War-era drug manufactured by the American government and since banned due to brain tumor-related deaths.
Split into simpler sentences: Glucuronolactone has received some notoriety due to urban legends that it was a Vietnam War-era drug manufactured by the American government. The rumor goes on to say that it was banned due to brain tumor-related deaths.