BEILSTEIN RING SEARCH SYSTEM .1. GENERAL DESIGN

One of the most significant advantages of an online database is the po ssibility of accessing the data in many different ways using different types of search criteria. The Beilstein Online Database (Domokos, L. Mikrochim. Acta 1986, II, 423-429), which is the largest factual data collection of organic chemistry, has more than 400 different search ke ys. It is available on two online hosts, Dialog and STN. The online ex perience has shown that the most frequently used access methods are th ose which select compounds by their structural properties, like full s tructure and substructure, chemical name, chemical name fragments, mol ecular formula, molecular weight, atom counts, and Lawson number. The Beilstein ring search system (BRSS) was developed to allow an easy and fast retrieval of compounds by exact or fuzzy definition of their emb edded ring systems. This paper gives a general overview of the BRSS it self and of the new database fields supporting the BRSS. An early stag e of the development has been reported previously (Domokos, L. In Soft ware Development in Chemistry; Gasteiger, J., Ed.; Springer-Verlag: Be rlin, 1990; pp 31-41).