Existing methods for coding chemical compounds are discussed and evaluated as to their suitability for documentation of chemical reactions, a new classification for chemical reactions is presented, and possibilities of automatic encoding are studied. (24 references) (Author)

The computerized conversion of Wiswesser Line Notations to Ring Codes, using a two-part approach, and the set of computer programs generated for the conversion of ring systems are described. (9 references) (Author)

A method of constructing a check digit for nonconventional chemical codes is described. (5 references) (Author)

Automatic processing of the bibliography on vapor-liquid equilibrium data is done by means of a specially developed mnemonic coding system. (Author/JB)

The boundary between two neighboring rings is called the fusion lines, which is enclosed by external segments called arcs. In the code, the separation of fusion line(s) from arcs takes place in such a way that proper matching is achieved. By this procedure, the structure of a compound is recreated. (Author)

Almost three million records covering approximately 175,000 chemical compounds and involving multiple disciplines have been recorded in the Army Antimalarial Drug Program. Maximum compartmentalization of files together with a complete method of interfacing files and a unique number system has made it possible to manage this system. (2 references)…

Two systems, WLN and Ringcode, for retrieving structural information were analyzed qualitatively and evaluated for a series of chemical compounds. The studies ranged from specific to generic questions and also involved retrieval by fragments. Neither system was completely satisfactory for all types of searches. (6 references) (Author)

Among other improvements in chemical nomenclature used in the Chemical Registry System, Chemical Abstracts Service intends to standardize the fundamental principles for naming cyclic structures so that procedures for the derivation of ring names can become more amenable to computer generation and translation. (Author/NH)

A computer system, named CORA, has been devised for coding chemical structures by fragmentation elements. It has been used to encode Markush formulas in patents according to the Ring codes used in the Ringdoc and Pestdoc services and results in an easy, speedy, reliable and inexpensive method. (4 references) (Author)

The TSS (Topological Screens System) for substructure search was applied to the CAS Registry file making it searchable on-line. The TSS screens and the use of the screen indexes are described. Statistics on screen assignment are provided, and the strengths and weaknesses of the system are discussed. (Author/NH)

The relative retrieval performances of the CA Integrated Subject File (CAISF), CA Condensates, and a Merged File created from these two data bases were measured. Retrieval performance is reported in terms of recall, precision values, and costs. (Author/JB)