Chemical Structure Search and Markush Structure Search

Chemical Structure

Chemical Structure Search and Markush Structure Search


Dr. Eugene A. Markush first made Markush claims in a patent titled “Pyrazolone Dye and Process of Making the Same,” published by the US Patent Office on August 26, 1924. A Markush structure is a chemical representation defining a group of related compounds. Almost all chemistry and pharmaceutical publications include a chemical structure or Markush structure.

Markush Structure

Markush Structure

In the scenario for “R” group is Cyanide, Hydroxyl, C1-8 alkyl group, COOH, CHO, C(O)Me, OCH3, amine, amide, sulfuric acid.

Enumerated compounds from above mentioned Markush structure and Markush entries.


Chemical structure searches are conducted to identify chemical structures that are identical or similar to a chemical structure of interest. Various databases are used to conduct the Markush chemical structure search.

1. The World Intellectual Property Organization (WIPO) – PATENTSCOPE

WIPO offers tools for patent search professionals providing access to millions of patent records from around the world. This allows them to gain valuable insights about their inventions and discoveries. The advantages of the WIPO database include advanced search options, a user-friendly interface, timely updates, and no cost. However, it’s important to note that the search may not be comprehensive.

2. STN

STN (Scientific & Technical Information Network) International is a joint operation between CAS and FIZ Karlsruhe. It provides access to data from Chemical Abstracts Service, Clarivate Analytics, the European Patent Office, and other patent databases. Key databases on STN include Derwent, WPISM, CAplus, and INPADOCDB/INPAFAMDB. In addition to these, STN also offers full-text patent databases from the European Patent Office (EPO), United States Patent and Trademark Office (USPTO), World Intellectual Property Organization (PCT), and more.

CAS REGISTRY – It is the world’s largest substance database. The main CAS databases are updated daily so we can access the latest reported scientific discoveries

CAplus – It is an integrated chemical and scientific resource of journals, patents, and reputable web sources, which is updated daily with new bibliographic records and updated weekly with indexing.

Other databases

We at MCRPL offer Chemical structure searches (Markush structure search, Exact structure search, IUPAC/Common name search, CAS number search, Family structure search, Substructure search, Fragments search, polymer search, etc.) and are proficient in conducting the structure search using commercial databases in a cost efficient manner. 

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