Development of System Translating Chemical Name into 2D-Structure (VII)

Abstract

The computer system has been developed to convert chemical name of organic compound to the 2D-structural formula. This report describes the process for recognizing stereochemical changes by skeletal modifications of natural product structure. The modifications are described by prefixes 'nor-','homo-','seco-','cyclo-' and 'abeo-'. The stereochemistry of fundamental parent structure on the orientated plane is represented using sequence rule based on locants of atoms connected to a chiral center, by informations of the target atom of alpha-beta, of up or down direction of bondage from the center to the least-prefered connected atom, and of right- or left-handed rotation of three connected atoms in order of preference around the center. Stereochemistry table of atoms presents the three informations of target,direction and rotation and is updated after each skeletal modification. Modification table of a center atom presents information of original connected atom and the replaced one by a modification. After generation of structural diagram, arrangement table of ring atom is generated, presenting location of a ring atom to be entrant or reentrant on each unit ring. Graphic representation of stereochemistry on the structural diagram is achieved by integrating those informations from the tables.