RESUMO
A chiral anthranilic pyrrolidine catalyst as a custom-made amine-catalyst was developed for the enantio- and diastereo selective Michael reaction of nitroalkenes with carbonyl compounds. In particular, a peptide-like catalyst in which an α-amino acid is attached to the anthranilic acid skeleton induced the high stereoselectivity of the reaction with aldehydes. Studies of the reaction mechanism indicated that the catalyst exhibits a divergent stereocontrol in the reaction, namely, steric control by a 2-substituted group on the catalyst and hydrogen-bonding control by a carboxylic acid group on the catalyst.
RESUMO
A captive female dugong at Toba Aquarium (Japan) was examined to describe the microbiota of its lower digestive tracts using the molecular-biological technique, a culture-independent method. The phylogenetic analysis of bacterial 16S rRNA genes was conducted for fecal samples, which were taken at 3 different periods. Based on phylogenetic analysis of these sequences, the representatives of six bacterial phyla could be identified: Actinobacteria (0.7%), Bacteroidetes (15%), Firmicutes (83.1%), Lentisphaerae (0.1%), Proteobacteria (0.1%), and Verrucomicrobia (1.0%), suggesting the existence of bacterial species newly found not only in the digestive tract but also in natural field.