Homologs, Isomers and Analogs
A homologous series is a family of chemically related compounds, the composition of which varies from member to member by CH2 * * *. Chemists knowing the properties of one member would in general know what to expect in adjacent members.
In the Henze case, certain propoxymethyl-hydantoins were found obvious over corresponding ethoxymethyl-hydantoins. There have been numerous other cases where the change from one adjacent homolog to another has been held obvious, but this alone is not conclusive if there is no motivation to make a change of any kind, as seen from In re Stemniski, 444 F.2d 581, 170 USPQ 343 (CCPA 1971), In re Lalty, 747 F.2d 703, 223 USPQ 1257 (Fed. Cir. 1984).
KeywordsAromatic Compound Chemical Compound Homologous Series Phosphinic Acid Prima Facie Case
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