SAN FRANCISCO — Medivation Inc.’s trial against a UCLA chemistry professor began for a San Francisco jury on Friday with the story of a fight over a valuable new drug for prostate cancer — and with an account, at times mind-numbing, of the chemistry underlying that new treatment.

“You’ll hear about the best that occurs in American research and business, and you’ll hear about the worst that can happen in American research and business,” said Latham & Watkins partner Max Grant in an opening statement for Medivation that was dominated by a crash course in molecular chemistry.