Markush group claims

When a Markush group is used for claiming a chemical invention, the members of the group either need to belong to a common or recognized class or share at least one... 

Let s consider a patent application that contains a claim including the Markush group we have drawn in Figure 7.1. The claim containing the naphthalene Markush is shown in Figure 7.2. A prior art search reveals the following disclosures ... 

Narrowed by adding an element or limitation to a previously recited element narrow claim can be dependent or independent. Adding a step narrows method claims. Adding an element to a closed (such as Markush Group) claim broadens, not narrows claim. 

This artificial genus received the name Markush when a chemist-inventor named Markush, in 1925, prevailed upon the Assistant Commissioner of Patents to approve as to form, a claim which read material selected from a group consisting of aniline, and homologues of aniline. This decision, which seemed to be dictated by necessity, established a precedent which has been extensively followed to this day and has conferred a sort of immortality upon the name of Markush. 

If you really want to know what a patent is about, skip to the end. The heart of a patent or application lies in the claims. This last section normally begins with a phrase like What is claimed is or The subject matter claimed is and proceeds to a numbered list spelling out the actual compounds the invention encompasses. In the end, exclusivity is granted only for claims that appear in the issued patent. These can differ markedly from the universe of compounds that fit the Markush structure in the earlier sections, and may not even include many of the example compounds. For instance, US 7,071,184 includes in the detailed description section a Markush structure with more than five pages worth of definitions of substituent groups and lists 64 specific compounds as examples, but only one single compound is allowed in the claims. ... 

Segment 1 denotes that a specific structure has been claimed in a patent in isolation, or as one of a very small group of specific compounds. Derwent is using Segment 1 as an efficiency factor in indexing, and in presentation to the user. For example, if there are 1,000 patents on production of aniline, the user would only wish to see one graphic aniline record, along with any representations of aniline as a possibility of a Markush. 

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