Derwent Markush Resource Database (DWPIM) on STN - Reference Manual
Patent literature is considered to be an important source of technical knowledge and it has been stated that a large portion of new knowledge is not published elsewhere. A significant part of this literature is classified as Chemistry patents, containing new chemical compounds, new ways of preparation, or new applications of known compounds. In general, the core of a patent claim in Chemistry is based on a chemical structure which could be generalized to broaden the scope of the respective claim. Any serious patent search must be able to find all relevant substances claimed in the patent literature, and this includes both specific structures as well as generalized (Markush) structures.