Markush structure
Markush structures (-R) are chemical symbols used to indicate a collection of chemicals with similar structures. They are commonly used in chemistry texts, and also in patent claims.
Markush structures are depicted with R groups, in which the side chain can be a structure type, e.g. 'cyclohexyl'.[1] This more general depiction of the molecule, versus detailing every atom in the molecule, is used to protect intellectual property. The company which files the patent makes a general claim for the usage of the molecule without revealing to their competitors the exact molecule for which they are declaring a useful application.[2]
In Patents
They are named after Dr Eugene A. Markush, founder of the Pharma Chemical Corporation in New Jersey. He was involved in a legal case that set a precedent for generic chemical structure patent filing.[1] The patent filing was US Application 611,637, filed January 9, 1923. Markush was awarded a patent from the US Patent Office for “Pyrazolone Dye and Process of Making the Same” on August 26, 1924.[2][3]
In describing a chemical, a Markush structure allows the patent-holder to list several active/effective structural formulas. Patent applicants are required to reveal their best known embodiment implementing their invention [4] and patent claims can be rejected or invalidated as indefinite if they are too vague.[4]
See also
References
- 1 2 Barnard, John M. (28 Oct 2009). "Markush Structure Searching" (PDF). Royal Society of Chemistry www.rsc.org. Retrieved 15 Jan 2014.
- 1 2 Gardner, Steve; Vinter, Andy. "Beyond Markush – Protecting Activity not Chemical Structure" (PDF). http://www.cresset-group.com/. Retrieved 15 Jan 2015. External link in
|website=(help) - ↑ http://www.google.com/patents/US1506316
- 1 2 http://www.uspto.gov/web/offices/pac/mpep/mpep-9015-appx-l.html#d0e302824912