Markush structures were named after Eugene Markush, the first inventor to
include them (successfully) in a U.S. patent back in the 1920s. In general,
a Markush structure is a chemical structure with multiple "functionally
equivalent" chemical entities allowed in one or more parts of the compound.
According to "Patent Law for the Nonlawyer" (Burton A. Amernick; 2nd edition,
1991), "In claims that recite... components of compositions, it is sometimes
important to claim, as alternatives, a group of consitituents that are
considered equivalent for the purposes of the invention.... It has been
permissible to claim such an artificial group, referred to as a 'Markush Group,'
ever since the inventor in the first case... won the right to do so."
If a compound being patented includes several Markush groups, you can see
that the number of possible compounds it covers could be vast. And no patent
databases generate all possible permutations and index them separately. So
patent searchers have the problem, when searching for specific chemicals in
patents, of trying to find all patents with Markush structures that would
include their chemicals, even though these patents' indexing would not include
the suitable specific compounds. This is where databases that permit searching
of chemical substructures are indispensible.
- definition written by Nancy Lambert at
http://www.questel.orbit.com/Piug/piugl99/0381.html
