Exhaustive generation of organic isomers. 5. Unsaturated optical and geometrical stereoisomers and a new CIP subrule

This work, based on graph theory, presents a US-CAMGEC software developed f or analysis, generation, and counting organic unsaturated stereoisomers wit h isolated or cumulated double bonds in structures that may contain chiral carbon and heteroatoms with variable valences within the molecule. A new ex tension to N_tuple notation was done for describing accordingly either Z, E , r, or s double bond and R, S stereoisomerism, Algorithms for transforming both constitutional isomer N_tuples to their corresponding graphs and grap hs to the corresponding configurational N_tuples were developed. Computatio nal implementation of Cahn-Ingold-Prelog (CIP) rules was developed includin g a new subrule for discriminating priorities to rank complex ligands alrea dy containing chiral stereocenters and having no different atomic number pa rtial ranks. Test results for families of symmetric and nonsymmetric hydroc arbons and their monohalogenated, mono- and dioxygenated, and mono- and din itrogenated derivatives are presented.