Intermolecular association and geometrical shape as two factors controlling chemical reactions
BIOLOGICAL phenomena are highly specific1–4 and much effort has been devoted to establishing the relationship between biological activity and molecular shape. We report here the sharp dependence of selectivity in the oxidation of a pair of thiols on their structures or on environment, the mode of each dependence of selectivity being controlled dominantly by their tendency towards intermolecular association.
Precise Discrimination between Butyl and Pentyl Groups in Molecular Aggregates
In oxidation of a pair of associating thiols, one with a straight-chain alkyl or a cyclic hydrocarbon group and the other with a butyl or pentyl group, it has been shown that a butyl group can be distinguished accurately from a pentyl group by a cyclopentyl group in aqueous ethanol.
Essential Oil Profiles of 168 Perilla Cultivars by Head Space Solid Phase Micro-extraction Gas Chromatography Mass Spectrometry
Abstract In order to comprehensively elucidate the chemical biosynthesis in Perillla (commonly used in traditional herbal medicine), an untargeted analysis based on Gas chromatography-Mass spectrometry was done to reveal the metabolites from 168 different species of Perilla, with 73 components were identified. The results based on the 168 samples, which can be classified into five chemotypes, reveals that different genetic background have a significant influence on the metabolic synthesis of Perilla. The results of heat map for the components of different species and the principal component analysis are implying that the Perilla chemotypes are clustered for characteristic compounds. This study, which used optimized solid-phase microextraction conditions to investigate volatile oil composition, expanded our knowledge of metabolic pathways in Perilla. The differences between chemotypes provide a scientific basis for distinguishing between Perilla species, which not only can improve the testing standards for essential oils from Perilla herbs, but also can be beneficial to Perilla breeding.