Piperoxan
Piperoxan, also known as benodaine, is a drug which was the first antihistamine to be discovered. This compound, derived from benzodioxan, was prepared in the early 1930s by Daniel Bovet and Ernest Fourneau at the Pasteur Institute in France. Formerly investigated by Fourneau as an α-adrenergic-blocking agent, they demonstrated that it also antagonized histamine-induced bronchospasm in guinea pigs, and published their findings in 1933. Bovet went on to win the 1957 Nobel Prize in Physiology or Medicine for his contribution, and one of their students, Anne-Marie Staub, published the first structure-activity relationship study of antihistamines in 1939.