Oka v. Youssefyeh

Oka (appellant) and Youssefyeh (respondent) argued an interference proceeding before the Board of Patent Appeals and Interferences, having both invented chemical compounds with certain desirable properties. Oka was the senior party, having filed first on October 31, 1980. Youssefyeh had filed later but sought to prove that he was in fact the first to invent, making him the junior party in the interference. Under 35 U.S.C. §102(g), one who invents first but files second may still be entitled to a patent, and the Board determines which party is so entitled. Within the broad class of chemical compounds claimed, various developments were observed by the court in determining where Youssefyeh’s invention date should rest. As between the two chemical compound subgroups of importance, 2-indanyl and 5-indanyl, Youssefyeh first acquired the idea of a particular 2-indanyl subgroup in February 1980 and it was put in writing. Though Youssefyeh claims that his conception date is February 1980, specific evidence showed that one of skill in the art was unable to create this compound at the time. Youssefyeh possessed a method of making a similar compound as of October 10, 1980 and was able to make the 5-indanyl subgroup with that method in December 1980. Finally, in January 1981, Youssefyeh was able to make the 2-indanyl compound. The district court held that Youssefyeh was the first to invent as of October 10, 1980. After the Board awarded Youssefyeh priority of invention, Oka appealed.