Development of a System for Translation of Chemical Name into 2D-Structure (VI)

The computer system has been developed to convert chemical name of organic compound to the 2D-structural formula. This report describes full support of nomenclature of natural products and related compounds recommended by IUPAC 1999 on this system. Stereochemical information on a chiral center atom of stereoparent, fundamental parent structure of natural product, is expressed by means of rotation and bond data obtained as follows. The atoms adjacent to a chiral center are arranged in order of increasing locant number. Rotation of the first three atoms in this order around the center is evaluated to be clockwise or anticlockwise on the plain of the standard structural diagram. Bond directed from the center to the 4th atom is evaluated to be up or down. Rotation around an achiral ring atom is also evaluated similarly. Ring atoms of stereoparent are classified into bridge atoms and base ring atoms. The bridge atom is here defined to have a stereochemical bond from the chiral center. Stereochemical indication alpha or beta must be given for the bond from chiral center to bridge or chain atom shown on the diagram of stereoparent structure. Notation about stereochemical change caused by alpha or beta is discussed. Modifications by nor, homo, seco, cyclo and abeo as well as ent and rac are also discussed. The final process to represent up and down bondage on the 2-D structural diagram is discussed in detail.