Novel regioselectivity: three-component cascade synthesis of unsymmetrical 1,4- and 1,2-dihydropyridines.

The three-component sequential reaction of alpha,beta-unsaturated aldehydes, amines, and enaminones proceeded smoothly to give 1,3,4-trisubstituted 1,4-dihydropyridines in aqueous DMF. Moreover, the unexpected regioselective formation of 1,2-dihydropyridines has been observed for the first time in such an approach. On the basis of a systematic study, the novel regioselectivity could be assigned both to steric and electronic effects originating from the amine partner.

[Studies on the Herba Plantaginis of different kinds and habitats by FTIR reflection spectroscopy-chemometrics analysis].

In the present paper, FTIR of different species obtained from different regions of sibling plantaginis were determined by Fourier transform infrared reflection spectroscopy (FTIRS), and thirty-five comparatively typical absorption peaks were selected and used to study genetic relationship, combined with chemometric methods. The phylogenetic cluster analysis revealed that three species could be divided into two groups based on the distance of 0.036, among which Plantago depressa Willd. was clustered with Plantago asiatica L. based on distance of 0.033, while clustered with Plantago virginica L. based on distance of 0.042, and the result was consistent with that of traditional taxology. The principal component analysis result revealed that the distances of Plantago asiatica L. in the similar environment are similar in three-dimensional FTIR chart, however, it is dispersive when obtained from different regions. This method is scientific, simple and direct, and has important theoretical and practical application value.