Specification of Molecular Chirality

Abstract

The topological analysis of chiral molecular models has provided the framework of a general system for the specification of their chirality. The application, made in and bejore 19S6, of this system to organic-chemical configurations is generally retained, but is redefined with respect to certain types of structure, largely in the light of experience gained since 1956 in the Beilstein Institute and elsewhere. The system is now extended to deal, on the one hand, with organic-chemical conformations, and, on the other, with inorganicchemical configurations to ligancy six. Matters arising in connexion with the transference of chiral specijications from model to name are considered, notably that of the symbiosis in nomenclature of expressions of the general system and of systems of confined scope.

Comparative solution equilibrium and structural studies of half-sandwich ruthenium(II)(η6-toluene) complexes of picolinate derivatives

“…On the other hand complex 2 crystallized together with a solvate water molecule and only one enantiomer could be found in the chiral space group P2 1 . The absolute configuration R Ru could be determined according to CIP convention [48], the Flack parameter is 0.01(5). The molecular structures of the studied complexes were directly compared to that of the benzene derivative [Ru( 6 -C 6 H 6 )(pic)(Cl)] defined previously (Ref.…”

Recommendations for the presentation of NMR structures of proteins and nucleic acids

“…For example, the ring carbons of Phe and Tyr lying in the plane with the smaller χ 2 torsion angle are designated as C δ1 and C ε1 . Indicated for reference in parentheses are the pro-R/pro-S designations for prochiral tetrahedral groups (with only the pro-R indicated as 'R') [25,26] and the E/Z designations for planar groups [27,28]. signments relative to the χ 2 torsion angle is needed to define the specific atom designators 1 and 2.…”

“…The phosphorus-bound oxygens are named O3′, O5′, OP1, and OP2. In the CIP rules (Cahn-Ingold-Prelog, [25,26] …”

“…For example, in a peptide, the backbone carbon and nitrogen atoms take precedence over other heavier atoms such as the carbonyl oxygen or cysteine C β [20]. Other- wise atom preferences follow standard conventions [25,26]. A given torsion angle θ about the BϪC bond of a molecule AϪ BϪCϪD (where A is the atom with highest preference attached to B, and D is the atom with highest preference attached to C) is the angle between the planes containing AϪBϪC and BϪCϪ D, or alternatively the angle between the projections of BϪA and CϪD onto a plane normal to BϪC.…”

The importance of the phenyl‐tropolone ‘aS’ configuration in colchicine's binding to tubulin

“…Although the results of antitumor activity and tubulin binding studies of a large number of cholchicinoids had indicated the importance of the spatial arrangement of the four methoxy groups in the drug-protein interaction, the mechanism of interaction is still not clearly understood. A recent report [6] Note: The italic letter a before the corresponding R and S denotes an axial chirality originating from a biaryl system as suggested by Calm et al [1] with the protein would therefore deserve special attention. Support for this hypothesis has now been …”