关键词:
CHEMICALS
摘要:
Reduced chemical graphs for specific chemical substances comprise summary descriptions of the gross structural features of these substances;an example is summarization in terms of only the ring and nonring components, giving a tree structure in which each node is either a cyclic or an acyclic component. Other bases for graph reduction are possible, including those in which the components are formed from the separate aggregates of carbon atoms and of heteroatoms. The reduced graph of a generic chemical structure is usually a multigraph, in which the identities of the variables are summarized in similar terms. The varieties and distributions of several types of reduced graphs created from almost 50 000 specific chemical substances in the Fine Chemicals Directory are characterized. The data provide qualitative guidance on the power of reduced graphs as retrieval keys when a database of generic structures described in this way is searched for queries that are complete specific or generic structures. The performance of several types of reduced graph, taken both singly and in combination, as retrieval keys for searches of generic chemical structures is reported. The test database is a small set of generic structures in which the variables are specific partial structures;the queries comprise both specific structures from patents and the generic structures of the test database itself. The results confirm the potential of reduced chemical graphs for high performance. © 1987, American Chemical Society. All rights reserved.