In the field of organic chemistry, Maitland Jones Jr. has a storied reputation. He taught the subject for decades, first at Princeton and then at New York University, and wrote an influential textbook. He received awards for his teaching, as well as recognition as one of N.Y.U.’s coolest professors.

But last spring, as the campus emerged from pandemic restrictions, 82 of his 350 students signed a petition against him.

Students said the high-stakes course — notorious for ending many a dream of medical school — was too hard, blaming Dr. Jones for their poor test scores.

The professor defended his standards. But just before the start of the fall semester, university deans terminated Dr. Jones’s contract.