The application that resulted in the '280 patent was the third of three successive applications, the first two of which were unsuccessful. In the first application, filed in 1957, Monsanto sought a patent on some 100 "compounds, including 3,4-DCPA and 3,4-DCAA (3,4-dichloroacetanilide), a chemical with some similar properties and a similar physical structure. Monsanto claimed that all the members of the class possessed "unusual and valuable herbicidal activity," while related compounds possessed "little or no herbicidal efficiency."