GENSAL

Barnard, J. M., M. F. Lynch, and S. M. Welford. 1981. Computer storage and retrieval of generic structures in chemical patents. 2. GENSAL, a formal language for the description of generic chemical structures. J. Chem. Inf. Comput. Sci. 21(3) 151—161. 

Figure 1. A composite generic structure expressed in GENSAL.

Barnard, J.M. Lynch, M.F. Welford, S.M. Computer Storage and Retrieval of Generic Chemical Structures in Patents, Part 2, GENSAL, A Formal Language for the Description of Generic Chemical Structures. J. Chem. Inf. Comput. Sci. 1981, 21, 151-161. 

Another example is GENSAL, which provides a means for the representation of generic queries in an experimental system for the storage and retrieval of the Markush structures that occur in chemical patents. Here, the language allows the specification of lists of alternative substituents, of variant positions of substitution on rings, and of ranges of numbers of atoms in carbon chains. Thus, these lists reflect the very wide range of types of structural description that are found in patents for chemical substances. 

Figure 4. The GENSAL, ECTR and ring/non-ring reduced graph representations of a generic structure...

In this discussion, a match exists between structures which are related to each other by community, i.e., they have at least one specific structure in common. It should be noted that a structure match is a match in terms of the GENSAL system, i.e., any structural differentiations which are not represented in GENSAL, e.g., stereochemistry, cannot be distinguished in the refined search. 

AUTOMATIC TRANSLATION OF GENSAL REPRESENTATIONS OF MARKUSH STRUCTURES INTO GREMAS FRAGMENT CODES AT IDC... 

INTRODUCTION WHY AUTOMATIC TRANSLATION OF GENSAL INTO GREMAS ... 

Since we have the GENSAL language (see Figure 2) for description of Markush structures , and software for translation of them into machine internal representations, we are able to derive search representations automatically. Great... 

The internal representation of GENSAL is called ECTR (Extended Connection Table Representation). It was described first by Barnard, Welford and Lynch in... 

Figure 9. Simple example of Markush structure in GENSAL...

Parts of the IDC GENSAL GREMAS System are implemented on a MS-DOS microcomputer, for instance the graphical input and the syntax analysis of... 

GENSAL. All other steps of processing are done on a mainframe computer. Most of the programs are written in the high level programming languages PASCAL and FORTRAN. 

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