A facile and sustainable electrochemical umpolung of bromide ion protocol was developed under mild reaction conditions. Transition metal catalysts and exogenous chemical oxidants were obviated for the bromination of C–H bond. Notably, graphite rod, which is commercially available at supermarkets and is inexpensive, was employed as the electrode material. This operationally easy and environmentally friendly approach accomplished the synthesis of 3-bromoindole in excellent yield and regioselectivity.
Without the use of catalysts and
oxidants, a facile and sustainable
electrochemical bromination protocol was developed. By introducing
the directing groups, the regioselectivity of pyridine derivatives
could be controlled at the meta-position utilizing
the inexpensive and safe bromine salts at room temperature. A variety
of brominated pyridine derivatives were obtained in 28–95%
yields, and the reaction could be readily performed at a gram scale.
By combining the installation and removing the directing group, the
concept of meta-bromination of pyridines could be
verified.
A small flagellate alga was isolated from the phycosphere of a toxic red tide dinoflagellate Alexandrium tamarense. Phylogenetic analysis and ultrastructural observations demonstrated that the small flagellate alga is a species belong to Ochrophyte Ochromonas sp. The process of ingesting bacteria by Ochromonas sp. was recorded by a time lapse capture under a light microscope. Through the use of different assemblages in the co-culture experiment, the species interactions in this phycosphere microenvironment were analyzed. We demonstrated that the growth of Ochromonas sp. was supported by bacteria. Three strains of bacteria ingested by Ochromonas sp. were isolated and identified to belong to α-, δ-and γ-Proteobacteria. The growth of A. tamarense was suppressed when co-cultured with bacteria. In contrast, Ochromonas sp. triggered the growth of A. tamarense by inhibiting the growth of algicidal bacteria. This result firstly demonstrated a positive effect of a flagellate on a dinoflagellate in the phycosphere of A. tamarense. Combined with other negative effects between dinoflagellates and bacteria or bacteria and flagellates, this study showed a series of clear interactions among dinoflagellate, bacterium, and flagellate in the dinoflagellate microenvironment.
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