RESUMEN
Amide is a fundamental group that is present in molecular structures of all domains of organic chemistry and the construction of this motif with high atom economy is the focus of the current research. Specifically, N-methyl amides are valuable building blocks in natural products and pharmaceutical science. Due to the volatile nature of methyl amine, the generation of N-methyl amides using simple acids with high atom economy is rare. Herein, we disclose an atom economic protocol to prepare this valuable motif under DABCO/Fe3O4 cooperative catalysis. This protocol is operationally simple and compatible with a range of aliphatic and (hetero)aromatic acids with very good yields (60-99%). Moreover, the Fe3O4 can be easily recovered and high efficiency is maintained for up to ten cycles.
RESUMEN
AIM To establish the HPLC characteristic chromatogram of Baqi Rougan Decoction reference sample,and to investigate its quantitative transmission laws.METHODS The contents of calycosin 7-O-glucoside,hesperidin,rosmarinic acid,curcumenol and nystose were determined.The transfer rates of decoction piece-aqueous decoction-reference sample were calculated,after which the paste-forming rate and pH value were recorded.RESULTS There were sixteen characteristic peaks in fifteen batches of reference samples with the similarities of 0.90,nine of which were identified.The average transfer rates of nystose and calycosin 7-O-glucoside in the reference sample were(83.14±6.25)%and(77.81±8.31)%,while those of rosmarinic acid and curcumenol in the aqueous decoction-reference sample were(81.71±6.27)%and(72.16±5.91)%,along with the average paste-forming rate and pH value of(38.91%±1.46%)and 5.13±0.08,respectively.CONCLUSION This stable and feasible method can provide a reference for the selection of preparation process and evaluation of key chemical properties for Baqi Rougan Decoction.